diff --git a/.gitignore b/.gitignore
index 58f29029c..c44fe6f29 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ bazel-*
 *.idea
 hash1
 hash2
+.DS_store
\ No newline at end of file
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index d217d5b4f..b08c0b31d 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -19,3 +19,5 @@ Laurent Le Brun <laurentlb@google.com>
 Nathan Harmata <nharmata@google.com>
 Oscar Boykin <oscar.boykin@gmail.com>
 Justine Alexandra Roberts Tunney <jart@google.com>
+Natan Silnitsky <natans@wix.com>
+Nadav Wexler <nadavwe@wix.com>
diff --git a/WORKSPACE b/WORKSPACE
index 833b8e577..0e5d8dab4 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -1,5 +1,7 @@
 workspace(name = "io_bazel_rules_scala")
 
+
+
 load("//scala:scala.bzl", "scala_repositories", "scala_mvn_artifact")
 scala_repositories()
 
@@ -28,4 +30,15 @@ maven_jar(
   artifact = scala_mvn_artifact("org.psywerx.hairyfotr:linter:0.1.13"),
   sha1 = "e5b3e2753d0817b622c32aedcb888bcf39e275b4")
 
+# test of strict deps (scalac plugin UT + E2E)
+maven_jar(
+    name = "com_google_guava_guava_21_0",
+    artifact = "com.google.guava:guava:21.0",
+    sha1 = "3a3d111be1be1b745edfa7d91678a12d7ed38709"
+)
 
+maven_jar(
+    name = "org_apache_commons_commons_lang_3_5",
+    artifact = "org.apache.commons:commons-lang3:3.5",
+    sha1 = "6c6c702c89bfff3cd9e80b04d668c5e190d588c6"
+)
\ No newline at end of file
diff --git a/scala/scala.bzl b/scala/scala.bzl
index fc9a6e789..780cfb3ed 100644
--- a/scala/scala.bzl
+++ b/scala/scala.bzl
@@ -149,7 +149,7 @@ def _collect_plugin_paths(plugins):
     return paths
 
 
-def _compile(ctx, cjars, dep_srcjars, buildijar):
+def _compile(ctx, cjars, dep_srcjars, buildijar, transitive_compile_jars=[], labels = {}):
     ijar_output_path = ""
     ijar_cmd_path = ""
     if buildijar:
@@ -162,9 +162,40 @@ def _compile(ctx, cjars, dep_srcjars, buildijar):
     all_srcjars = set(srcjars + list(dep_srcjars))
     # look for any plugins:
     plugins = _collect_plugin_paths(ctx.attr.plugins)
+    dependency_analyzer_plugin_jars = []
+    dependency_analyzer_mode_soon_to_be_removed = "off"
+    compiler_classpath_jars = cjars
+    optional_scalac_args = ""
+
+    if not is_dependency_analyzer_off(ctx):
+    # "off" mode is used as a feature toggle, that preserves original behaviour
+        dependency_analyzer_mode_soon_to_be_removed = ctx.attr.dependency_analyzer_mode_soon_to_be_removed
+        dep_plugin = ctx.attr._dependency_analyzer_plugin
+        plugins += [f.path for f in dep_plugin.files]
+        dependency_analyzer_plugin_jars = ctx.files._dependency_analyzer_plugin
+        compiler_classpath_jars = transitive_compile_jars
+
+        direct_jars = ",".join([j.path for j in cjars])
+        indirect_jars = ",".join([j.path for j in transitive_compile_jars])
+        indirect_targets = ",".join([labels[j.path] for j in transitive_compile_jars])
+        current_target = str(ctx.label)
+
+        optional_scalac_args = """
+DirectJars: {direct_jars}
+IndirectJars: {indirect_jars}
+IndirectTargets: {indirect_targets}
+CurrentTarget: {current_target}
+        """.format(
+              direct_jars=direct_jars,
+              indirect_jars=indirect_jars,
+              indirect_targets=indirect_targets,
+              current_target = current_target
+              )
+
     plugin_arg = ",".join(list(plugins))
 
-    compiler_classpath = ":".join([j.path for j in cjars])
+    compiler_classpath = ":".join([j.path for j in compiler_classpath_jars])
+
 
     scalac_args = """
 Classpath: {cp}
@@ -185,6 +216,7 @@ ResourceSrcs: {resource_src}
 ResourceStripPrefix: {resource_strip_prefix}
 ScalacOpts: {scala_opts}
 SourceJars: {srcjars}
+DependencyAnalyzerMode: {dependency_analyzer_mode_soon_to_be_removed}
 """.format(
         out=ctx.outputs.jar.path,
         manifest=ctx.outputs.manifest.path,
@@ -197,7 +229,7 @@ SourceJars: {srcjars}
         ijar_out=ijar_output_path,
         ijar_cmd_path=ijar_cmd_path,
         srcjars=",".join([f.path for f in all_srcjars]),
-        javac_opts=" ".join(ctx.attr.javacopts) + 
+        javac_opts=" ".join(ctx.attr.javacopts) +
                 #  these are the flags passed to javac, which needs them prefixed by -J
                 " ".join(["-J" + flag for flag in ctx.attr.javac_jvm_flags]),
         javac_path=ctx.executable._javac.path,
@@ -208,12 +240,14 @@ SourceJars: {srcjars}
           ),
         resource_strip_prefix=ctx.attr.resource_strip_prefix,
         resource_jars=",".join([f.path for f in ctx.files.resource_jars]),
+        dependency_analyzer_mode_soon_to_be_removed = dependency_analyzer_mode_soon_to_be_removed,
         )
     argfile = ctx.new_file(
       ctx.outputs.jar,
       "%s_worker_input" % ctx.label.name
     )
-    ctx.file_action(output=argfile, content=scalac_args)
+
+    ctx.file_action(output=argfile, content=scalac_args + optional_scalac_args)
 
     outs = [ctx.outputs.jar]
     if buildijar:
@@ -221,12 +255,13 @@ SourceJars: {srcjars}
     # _jdk added manually since _java doesn't currently setup runfiles
     # _scalac, as a java_binary, should already have it in its runfiles; however,
     # adding does ensure _java not orphaned if _scalac ever was not a java_binary
-    ins = (list(cjars) +
+    ins = (list(compiler_classpath_jars) +
            list(dep_srcjars) +
            list(srcjars) +
            list(sources) +
            ctx.files.srcs +
            ctx.files.plugins +
+           dependency_analyzer_plugin_jars +
            ctx.files.resources +
            ctx.files.resource_jars +
            ctx.files._jdk +
@@ -255,14 +290,14 @@ SourceJars: {srcjars}
       )
 
 
-def _compile_or_empty(ctx, jars, srcjars, buildijar):
+def _compile_or_empty(ctx, jars, srcjars, buildijar, transitive_compile_jars, jars2labels):
     # We assume that if a srcjar is present, it is not empty
     if len(ctx.files.srcs) + len(srcjars) == 0:
         _build_nosrc_jar(ctx, buildijar)
         #  no need to build ijar when empty
         return struct(ijar=ctx.outputs.jar, class_jar=ctx.outputs.jar)
     else:
-        _compile(ctx, jars, srcjars, buildijar)
+        _compile(ctx, jars, srcjars, buildijar, transitive_compile_jars, jars2labels)
         ijar = None
         if buildijar:
             ijar = ctx.outputs.ijar
@@ -351,35 +386,113 @@ def collect_srcjars(targets):
             srcjars += [target.srcjars.srcjar]
     return srcjars
 
+def add_labels_of_jars_to(jars2labels, dependency, all_jars):
+  for jar in all_jars:
+    add_label_of_jar_to(jars2labels, dependency, jar)
+
+
+def add_label_of_jar_to(jars2labels, dependency, jar):
+ if label_already_exists(jars2labels, jar):
+   return
+
+ # skylark exposes only labels of direct dependencies.
+ # to get labels of indirect dependencies we collect them from the providers transitively
+ if provider_of_dependency_contains_label_of(dependency, jar):
+   jars2labels[jar.path] = dependency.jars_to_labels[jar.path]
+ else:
+   jars2labels[jar.path] = dependency.label
+
+
+def label_already_exists(jars2labels, jar):
+  return jar.path in jars2labels
+
+def provider_of_dependency_contains_label_of(dependency, jar):
+  return hasattr(dependency, "jars_to_labels") and jar.path in dependency.jars_to_labels
+
+def dep_target_contains_ijar(dep_target):
+  return hasattr(dep_target, 'scala') and hasattr(dep_target.scala, 'outputs') and hasattr(dep_target.scala.outputs, 'ijar')
+
+def _collect_jars_when_dependency_analyzer_is_off(dep_targets):
+  compile_jars = depset()
+  runtime_jars = depset()
+
+  for dep_target in dep_targets:
+    if java_common.provider in dep_target:
+        java_provider = dep_target[java_common.provider]
+        compile_jars += java_provider.compile_jars
+        runtime_jars += java_provider.transitive_runtime_jars
+    else:
+        # support http_file pointed at a jar. http_jar uses ijar,
+        # which breaks scala macros
+        compile_jars += dep_target.files
+        runtime_jars += dep_target.files
+
+  return struct(compile_jars = compile_jars, transitive_runtime_jars = runtime_jars, jars2labels = {}, transitive_compile_jars = depset())
+
+def _collect_jars_when_dependency_analyzer_is_on(dep_targets):
+  transitive_compile_jars = depset()
+  jars2labels = {}
+  compile_jars = depset()
+  runtime_jars = depset()
+
+  for dep_target in dep_targets:
+    if dep_target_contains_ijar(dep_target):
+        transitive_compile_jars += [dep_target.scala.outputs.ijar]
+    if hasattr(dep_target, 'transitive_compile_jars'):
+        transitive_compile_jars += dep_target.transitive_compile_jars
+    if java_common.provider in dep_target:
+        java_provider = dep_target[java_common.provider]
+        compile_jars += java_provider.compile_jars
+        transitive_compile_jars += java_provider.compile_jars
+        runtime_jars += java_provider.transitive_runtime_jars
+    else:
+        # support http_file pointed at a jar. http_jar uses ijar,
+        # which breaks scala macros
+        compile_jars += dep_target.files
+        runtime_jars += dep_target.files
+        transitive_compile_jars += dep_target.files
+
+    add_labels_of_jars_to(jars2labels, dep_target, transitive_compile_jars)
 
-def _collect_jars(targets):
+  return struct(compile_jars = compile_jars, transitive_runtime_jars = runtime_jars, jars2labels = jars2labels, transitive_compile_jars = transitive_compile_jars)
+
+def _collect_jars(dep_targets, dependency_analyzer_is_off = True):
     """Compute the runtime and compile-time dependencies from the given targets"""  # noqa
-    compile_jars = depset()
-    runtime_jars = depset()
-    for target in targets:
-        if java_common.provider in target:
-            java_provider = target[java_common.provider]
-            compile_jars += java_provider.compile_jars
-            runtime_jars += java_provider.transitive_runtime_jars
-        else:
-            # support http_file pointed at a jar. http_jar uses ijar,
-            # which breaks scala macros
-            compile_jars += target.files
-            runtime_jars += target.files
 
-    return struct(compile_jars = compile_jars, transitive_runtime_jars = runtime_jars)
+    if dependency_analyzer_is_off:
+      return _collect_jars_when_dependency_analyzer_is_off(dep_targets)
+    else:
+      return _collect_jars_when_dependency_analyzer_is_on(dep_targets)
+
+def is_dependency_analyzer_off(ctx):
+  if not hasattr(ctx.attr, 'dependency_analyzer_mode_soon_to_be_removed'):
+    return True
+
+  if ctx.attr.dependency_analyzer_mode_soon_to_be_removed not in ["error", "warn", "off"]:
+     fail("Incorrect mode of dependency analyzer plugin! Mode must be 'error', 'warn' or 'off'")
+
+  return ctx.attr.dependency_analyzer_mode_soon_to_be_removed == "off"
+
 
 # Extract very common code out from dependency analysis into single place
 # automatically adds dependency on scala-library and scala-reflect
 # collects jars from deps, runtime jars from runtime_deps, and
 def _collect_jars_from_common_ctx(ctx, extra_deps = [], extra_runtime_deps = []):
+
+    dependency_analyzer_is_off = is_dependency_analyzer_off(ctx)
+
     # Get jars from deps
     auto_deps = [ctx.attr._scalalib, ctx.attr._scalareflect]
-    deps_jars = _collect_jars(ctx.attr.deps + auto_deps + extra_deps)
-    (cjars, transitive_rjars) = (deps_jars.compile_jars, deps_jars.transitive_runtime_jars)
-    transitive_rjars += _collect_jars(
-        ctx.attr.runtime_deps + extra_runtime_deps).transitive_runtime_jars
-    return struct(compile_jars = cjars, transitive_runtime_jars = transitive_rjars)
+    deps_jars = _collect_jars(ctx.attr.deps + auto_deps + extra_deps, dependency_analyzer_is_off)
+    (cjars, transitive_rjars, jars2labels, transitive_compile_jars) = (deps_jars.compile_jars, deps_jars.transitive_runtime_jars, deps_jars.jars2labels, deps_jars.transitive_compile_jars)
+
+    runtime_dep_jars =  _collect_jars(ctx.attr.runtime_deps + extra_runtime_deps, dependency_analyzer_is_off)
+    transitive_rjars += runtime_dep_jars.transitive_runtime_jars
+
+    if not dependency_analyzer_is_off:
+      jars2labels.update(runtime_dep_jars.jars2labels)
+
+    return struct(compile_jars = cjars, transitive_runtime_jars = transitive_rjars, jars2labels=jars2labels, transitive_compile_jars = transitive_compile_jars)
 
 def _lib(ctx, non_macro_lib):
     # Build up information from dependency-like attributes
@@ -391,7 +504,7 @@ def _lib(ctx, non_macro_lib):
     (cjars, transitive_rjars) = (jars.compile_jars, jars.transitive_runtime_jars)
 
     write_manifest(ctx)
-    outputs = _compile_or_empty(ctx, cjars, srcjars, non_macro_lib)
+    outputs = _compile_or_empty(ctx, cjars, srcjars, non_macro_lib, jars.transitive_compile_jars, jars.jars2labels)
 
     transitive_rjars += [ctx.outputs.jar]
 
@@ -447,6 +560,8 @@ def _lib(ctx, non_macro_lib):
         # this information through, and it is up to the new_targets
         # to filter and make sense of this information.
         extra_information=_collect_extra_information(ctx.attr.deps),
+        jars_to_labels = jars.jars2labels,
+        transitive_compile_jars = jars.transitive_compile_jars,
       )
 
 
@@ -464,9 +579,9 @@ def _scala_macro_library_impl(ctx):
   return _lib(ctx, False)  # don't build the ijar for macros
 
 # Common code shared by all scala binary implementations.
-def _scala_binary_common(ctx, cjars, rjars):
+def _scala_binary_common(ctx, cjars, rjars, transitive_compile_time_jars, jars2labels):
   write_manifest(ctx)
-  outputs = _compile_or_empty(ctx, cjars, [], False)  # no need to build an ijar for an executable
+  outputs = _compile_or_empty(ctx, cjars, [], False, transitive_compile_time_jars, jars2labels)  # no need to build an ijar for an executable
   _build_deployable(ctx, list(rjars))
 
   java_wrapper = ctx.new_file(ctx.label.name + "_wrapper.sh")
@@ -510,7 +625,7 @@ def _scala_binary_impl(ctx):
       main_class = ctx.attr.main_class,
       jvm_flags = ctx.attr.jvm_flags,
   )
-  return _scala_binary_common(ctx, cjars, transitive_rjars)
+  return _scala_binary_common(ctx, cjars, transitive_rjars, jars.transitive_compile_jars, jars.jars2labels)
 
 def _scala_repl_impl(ctx):
   # need scala-compiler for MainGenericRunner below
@@ -541,7 +656,7 @@ trap finish EXIT
 """,
   )
 
-  return _scala_binary_common(ctx, cjars, transitive_rjars)
+  return _scala_binary_common(ctx, cjars, transitive_rjars, jars.transitive_compile_jars, jars.jars2labels)
 
 def _scala_test_impl(ctx):
     if len(ctx.attr.suites) != 0:
@@ -551,13 +666,18 @@ def _scala_test_impl(ctx):
     jars = _collect_jars_from_common_ctx(ctx,
         extra_runtime_deps = [ctx.attr._scalatest_reporter, ctx.attr._scalatest_runner],
     )
-    (cjars, transitive_rjars) = (jars.compile_jars, jars.transitive_runtime_jars)
+    (cjars, transitive_rjars, transitive_compile_jars, jars_to_labels) = (jars.compile_jars, jars.transitive_runtime_jars,
+      jars.transitive_compile_jars, jars.jars2labels)
     # _scalatest is an http_jar, so its compile jar is run through ijar
     # however, contains macros, so need to handle separately
     scalatest_jars = _collect_jars([ctx.attr._scalatest]).transitive_runtime_jars
     cjars += scalatest_jars
     transitive_rjars += scalatest_jars
 
+    if is_dependency_analyzer_off(ctx):
+      transitive_compile_jars += scalatest_jars
+      add_labels_of_jars_to(jars_to_labels, ctx.attr._scalatest, scalatest_jars)
+
     transitive_rjars += [ctx.outputs.jar]
 
     args = " ".join([
@@ -573,7 +693,7 @@ def _scala_test_impl(ctx):
         jvm_flags = ctx.attr.jvm_flags,
         args = args,
     )
-    return _scala_binary_common(ctx, cjars, transitive_rjars)
+    return _scala_binary_common(ctx, cjars, transitive_rjars, transitive_compile_jars, jars_to_labels)
 
 def _gen_test_suite_flags_based_on_prefixes_and_suffixes(ctx, archive):
     return struct(testSuiteFlag = "-Dbazel.test_suite=io.bazel.rulesscala.test_discovery.DiscoveredTestSuite",
@@ -601,7 +721,7 @@ def _scala_junit_test_impl(ctx):
         jvm_flags = launcherJvmFlags + ctx.attr.jvm_flags,
     )
 
-    return _scala_binary_common(ctx, cjars, transitive_rjars)
+    return _scala_binary_common(ctx, cjars, transitive_rjars, jars.transitive_compile_jars, jars.jars2labels)
 
 _launcher_template = {
   "_java_stub_template": attr.label(default=Label("@java_stub_template//file")),
@@ -643,7 +763,7 @@ _junit_resolve_deps = {
 }
 
 # Common attributes reused across multiple rules.
-_common_attrs = {
+_common_attrs_for_plugin_bootstrapping = {
   "srcs": attr.label_list(
       allow_files=_scala_srcjar_filetype),
   "deps": attr.label_list(),
@@ -661,18 +781,40 @@ _common_attrs = {
   "print_compile_time": attr.bool(default=False, mandatory=False),
 }
 
+_common_attrs = _common_attrs_for_plugin_bootstrapping + {
+  # dependency_analyzer_mode_soon_to_be_removed will be replaced by using command line flag called 'strict_java_deps' (https://github.com/bazelbuild/bazel/issues/3295)
+  # switching mode to "on" means that ANY API change in a target's transitive dependencies will trigger a recompilation of that target,
+  # on the other hand any internal change (i.e. on code that ijar omits) WON’T trigger recompilation by transitive dependencies
+  "dependency_analyzer_mode_soon_to_be_removed": attr.string(default="off", mandatory=False),
+  "_dependency_analyzer_plugin": attr.label(default=Label("@io_bazel_rules_scala//third_party/plugin/src/main:dependency_analyzer"), allow_files=_jar_filetype, mandatory=False),
+}
+
+library_attrs = {
+  "main_class": attr.string(),
+  "exports": attr.label_list(allow_files=False),
+}
+
+library_outputs = {
+  "jar": "%{name}.jar",
+  "deploy_jar": "%{name}_deploy.jar",
+  "ijar": "%{name}_ijar.jar",
+  "manifest": "%{name}_MANIFEST.MF",
+}
+
 scala_library = rule(
   implementation=_scala_library_impl,
   attrs={
-      "main_class": attr.string(),
-      "exports": attr.label_list(allow_files=False),
-      } + _implicit_deps + _common_attrs + _resolve_deps,
-  outputs={
-      "jar": "%{name}.jar",
-      "deploy_jar": "%{name}_deploy.jar",
-      "ijar": "%{name}_ijar.jar",
-      "manifest": "%{name}_MANIFEST.MF",
-      },
+      } + _implicit_deps + _common_attrs + library_attrs + _resolve_deps,
+  outputs=library_outputs,
+)
+
+# the scala compiler plugin used for dependency analysis is compiled using `scala_library`.
+# in order to avoid cyclic dependencies `scala_library_for_plugin_bootstrapping` was created for this purpose,
+# which does not contain plugin related attributes, and thus avoids the cyclic dependency issue
+scala_library_for_plugin_bootstrapping = rule(
+  implementation=_scala_library_impl,
+  attrs= _implicit_deps + library_attrs + _resolve_deps + _common_attrs_for_plugin_bootstrapping,
+  outputs=library_outputs,
 )
 
 scala_macro_library = rule(
diff --git a/src/java/io/bazel/rulesscala/scalac/CompileOptions.java b/src/java/io/bazel/rulesscala/scalac/CompileOptions.java
index 41bb4ecb9..e57a334ba 100644
--- a/src/java/io/bazel/rulesscala/scalac/CompileOptions.java
+++ b/src/java/io/bazel/rulesscala/scalac/CompileOptions.java
@@ -22,6 +22,11 @@ public class CompileOptions {
   final public Map<String, String> resourceFiles;
   final public String resourceStripPrefix;
   final public String[] resourceJars;
+  final public String[] directJars;
+  final public String[] indirectJars;
+  final public String[] indirectTargets;
+  final public String dependencyAnalyzerMode;
+  final public String currentTarget;
 
   public CompileOptions(List<String> args) {
     Map<String, String> argMap = buildArgMap(args);
@@ -52,6 +57,13 @@ public CompileOptions(List<String> args) {
     resourceFiles = getResources(argMap);
     resourceStripPrefix = getOrEmpty(argMap, "ResourceStripPrefix");
     resourceJars = getCommaList(argMap, "ResourceJars");
+
+    directJars = getCommaList(argMap, "DirectJars");
+    indirectJars = getCommaList(argMap, "IndirectJars");
+    indirectTargets = getCommaList(argMap, "IndirectTargets");
+
+    dependencyAnalyzerMode = getOrElse(argMap, "DependencyAnalyzerMode", "off");
+    currentTarget = getOrElse(argMap, "CurrentTarget", "NA");
   }
 
   private static Map<String, String> getResources(Map<String, String> args) {
@@ -96,10 +108,14 @@ private static String[] getCommaList(Map<String, String> m, String k) {
   }
 
   private static String getOrEmpty(Map<String, String> m, String k) {
-    if(m.containsKey(k)) {
-      return m.get(k);
+    return getOrElse(m, k, "");
+  }
+
+  private static String getOrElse(Map<String, String> attrs, String key, String defaultValue) {
+    if(attrs.containsKey(key)) {
+      return attrs.get(key);
     } else {
-      return "";
+      return defaultValue;
     }
   }
 
diff --git a/src/java/io/bazel/rulesscala/scalac/ScalacProcessor.java b/src/java/io/bazel/rulesscala/scalac/ScalacProcessor.java
index a83250661..736b76239 100644
--- a/src/java/io/bazel/rulesscala/scalac/ScalacProcessor.java
+++ b/src/java/io/bazel/rulesscala/scalac/ScalacProcessor.java
@@ -17,11 +17,7 @@
 import java.nio.file.Paths;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Enumeration;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.Map.Entry;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
@@ -187,7 +183,45 @@ private static boolean matchesFileExtensions(String fileName, String[] extension
     return false;
   }
 
+  private static String[] encodeBazelTargets(String[] targets) {
+    return Arrays.stream(targets)
+            .map(ScalacProcessor::encodeBazelTarget)
+            .toArray(String[]::new);
+  }
+
+  private static String encodeBazelTarget(String target) {
+    return target.replace(":", ";");
+  }
+
+  private static boolean isModeEnabled(String mode) {
+    return !"off".equals(mode);
+  }
+
+  private static String[] getPluginParamsFrom(CompileOptions ops) {
+    String[] pluginParams;
+
+    if (isModeEnabled(ops.dependencyAnalyzerMode)) {
+      String[] targets = encodeBazelTargets(ops.indirectTargets);
+      String currentTarget = encodeBazelTarget(ops.currentTarget);
+
+      String[] pluginParamsInUse = {
+              "-P:dependency-analyzer:direct-jars:" + String.join(":", ops.directJars),
+              "-P:dependency-analyzer:indirect-jars:" + String.join(":", ops.indirectJars),
+              "-P:dependency-analyzer:indirect-targets:" + String.join(":", targets),
+              "-P:dependency-analyzer:mode:" + ops.dependencyAnalyzerMode,
+              "-P:dependency-analyzer:current-target:" + currentTarget,
+      };
+      pluginParams = pluginParamsInUse;
+    } else {
+      pluginParams = new String[0];
+    }
+    return pluginParams;
+  }
+
   private static void compileScalaSources(CompileOptions ops, String[] scalaSources, Path tmpPath) throws IllegalAccessException {
+
+    String[] pluginParams = getPluginParamsFrom(ops);
+
     String[] constParams = {
       "-classpath",
       ops.classpath,
@@ -199,6 +233,7 @@ private static void compileScalaSources(CompileOptions ops, String[] scalaSource
       ops.scalaOpts,
       ops.pluginArgs,
       constParams,
+      pluginParams,
       scalaSources);
 
     MainClass comp = new MainClass();
diff --git a/test/src/main/scala/scala/test/strict_deps/no_recompilation/A.scala b/test/src/main/scala/scala/test/strict_deps/no_recompilation/A.scala
new file mode 100644
index 000000000..b673edef8
--- /dev/null
+++ b/test/src/main/scala/scala/test/strict_deps/no_recompilation/A.scala
@@ -0,0 +1,7 @@
+package scala.test.strict_deps.no_recompilation;
+
+object A {
+	def foo = {
+		B.foo
+	}
+}
\ No newline at end of file
diff --git a/test/src/main/scala/scala/test/strict_deps/no_recompilation/B.scala b/test/src/main/scala/scala/test/strict_deps/no_recompilation/B.scala
new file mode 100644
index 000000000..c5f952ed0
--- /dev/null
+++ b/test/src/main/scala/scala/test/strict_deps/no_recompilation/B.scala
@@ -0,0 +1,7 @@
+package scala.test.strict_deps.no_recompilation;
+
+object B {
+	def foo = {
+		C.foo
+	}
+}
\ No newline at end of file
diff --git a/test/src/main/scala/scala/test/strict_deps/no_recompilation/BUILD b/test/src/main/scala/scala/test/strict_deps/no_recompilation/BUILD
new file mode 100644
index 000000000..005c7dd47
--- /dev/null
+++ b/test/src/main/scala/scala/test/strict_deps/no_recompilation/BUILD
@@ -0,0 +1,28 @@
+package(default_visibility = ["//visibility:public"])
+load("//scala:scala.bzl", "scala_library", "scala_test", "scala_binary")
+
+scala_library(
+    name="transitive_dependency_user",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],    
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="direct_dependency",
+    srcs=[
+        "B.scala",
+        ],
+    deps = ["transitive_dependency"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="transitive_dependency",
+    srcs=[
+        "C.scala",
+        ],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
\ No newline at end of file
diff --git a/test/src/main/scala/scala/test/strict_deps/no_recompilation/C.scala b/test/src/main/scala/scala/test/strict_deps/no_recompilation/C.scala
new file mode 100644
index 000000000..4bebb08cc
--- /dev/null
+++ b/test/src/main/scala/scala/test/strict_deps/no_recompilation/C.scala
@@ -0,0 +1,7 @@
+package scala.test.strict_deps.no_recompilation;
+
+object C {
+	def foo = {
+		println("orig")
+	}
+}
diff --git a/test_expect_failure/dep_analyzer_modes/A.scala b/test_expect_failure/dep_analyzer_modes/A.scala
new file mode 100644
index 000000000..a50dab0f7
--- /dev/null
+++ b/test_expect_failure/dep_analyzer_modes/A.scala
@@ -0,0 +1,8 @@
+package test_expect_failure.dep_analyzer_modes
+
+object A {
+  def foo = {
+    B.foo
+    C.foo
+  }
+}
\ No newline at end of file
diff --git a/test_expect_failure/dep_analyzer_modes/B.scala b/test_expect_failure/dep_analyzer_modes/B.scala
new file mode 100644
index 000000000..2f4dcd3d4
--- /dev/null
+++ b/test_expect_failure/dep_analyzer_modes/B.scala
@@ -0,0 +1,7 @@
+package test_expect_failure.dep_analyzer_modes
+
+object B {
+  def foo = {
+    C.foo
+  }
+}
\ No newline at end of file
diff --git a/test_expect_failure/dep_analyzer_modes/BUILD b/test_expect_failure/dep_analyzer_modes/BUILD
new file mode 100644
index 000000000..ec41ed682
--- /dev/null
+++ b/test_expect_failure/dep_analyzer_modes/BUILD
@@ -0,0 +1,56 @@
+package(default_visibility = ["//visibility:public"])
+load("//scala:scala.bzl", "scala_library", "scala_binary", "scala_test")
+
+scala_library(
+    name="error_mode",
+    dependency_analyzer_mode_soon_to_be_removed="error",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],
+)
+
+scala_library(
+    name="warn_mode",
+    dependency_analyzer_mode_soon_to_be_removed="warn",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],
+)
+
+scala_library(
+    name="weird_mode",
+    dependency_analyzer_mode_soon_to_be_removed="kuki_buki",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],
+)
+
+scala_library(
+    name="off_mode",
+    dependency_analyzer_mode_soon_to_be_removed="off",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],
+)
+
+
+scala_library(
+    name="direct_dependency",
+    dependency_analyzer_mode_soon_to_be_removed="error",
+    srcs=[
+        "B.scala",
+        ],
+    deps = ["transitive_dependency"],
+)
+
+scala_library(
+    name="transitive_dependency",
+    dependency_analyzer_mode_soon_to_be_removed="error",
+    srcs=[
+        "C.scala",
+        ],
+)
\ No newline at end of file
diff --git a/test_expect_failure/dep_analyzer_modes/C.scala b/test_expect_failure/dep_analyzer_modes/C.scala
new file mode 100644
index 000000000..a4f0ee834
--- /dev/null
+++ b/test_expect_failure/dep_analyzer_modes/C.scala
@@ -0,0 +1,7 @@
+package test_expect_failure.dep_analyzer_modes
+
+object C {
+  def foo = {
+    println("in C")
+  }
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/external_deps/A.scala b/test_expect_failure/missing_direct_deps/external_deps/A.scala
new file mode 100644
index 000000000..ffb9e5a43
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/external_deps/A.scala
@@ -0,0 +1,8 @@
+package test_expect_failure.missing_direct_deps.external_deps
+
+object A {
+	def foo = {
+		B.foo
+		com.google.common.base.Strings.commonPrefix("abc", "abcd")
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/external_deps/B.scala b/test_expect_failure/missing_direct_deps/external_deps/B.scala
new file mode 100644
index 000000000..32f5ae73a
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/external_deps/B.scala
@@ -0,0 +1,8 @@
+package test_expect_failure.missing_direct_deps.external_deps
+
+object B {
+	def foo = {
+		println("in B")
+		com.google.common.base.Strings.commonPrefix("abc", "abcd")
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/external_deps/BUILD b/test_expect_failure/missing_direct_deps/external_deps/BUILD
new file mode 100644
index 000000000..0dc06d9e9
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/external_deps/BUILD
@@ -0,0 +1,20 @@
+package(default_visibility = ["//visibility:public"])
+load("//scala:scala.bzl", "scala_library", "scala_test")
+
+scala_library(
+    name="transitive_external_dependency_user",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["external_dependency_user"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="external_dependency_user",
+    srcs=[
+        "B.scala",
+        ],
+    deps = ["@com_google_guava_guava_21_0//jar"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/external_deps_file_group/A.scala b/test_expect_failure/missing_direct_deps/external_deps_file_group/A.scala
new file mode 100644
index 000000000..748954c15
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/external_deps_file_group/A.scala
@@ -0,0 +1,8 @@
+package test_expect_failure.missing_direct_deps.external_deps_file_group
+
+object A {
+	def foo = {
+		B.foo
+		com.google.common.base.Strings.commonPrefix("abc", "abcd")
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/external_deps_file_group/B.scala b/test_expect_failure/missing_direct_deps/external_deps_file_group/B.scala
new file mode 100644
index 000000000..bdf49e8cc
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/external_deps_file_group/B.scala
@@ -0,0 +1,8 @@
+package test_expect_failure.missing_direct_deps.external_deps_file_group
+
+object B {
+	def foo = {
+		println("in B")
+		com.google.common.base.Strings.commonPrefix("abc", "abcd")
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/external_deps_file_group/BUILD b/test_expect_failure/missing_direct_deps/external_deps_file_group/BUILD
new file mode 100644
index 000000000..d5f6e6c32
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/external_deps_file_group/BUILD
@@ -0,0 +1,20 @@
+package(default_visibility = ["//visibility:public"])
+load("//scala:scala.bzl", "scala_library", "scala_test")
+
+scala_library(
+    name="transitive_external_dependency_user",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["external_dependency_user"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="external_dependency_user",
+    srcs=[
+        "B.scala",
+        ],
+    deps = ["@com_google_guava_guava_21_0//jar:file"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/internal_deps/A.scala b/test_expect_failure/missing_direct_deps/internal_deps/A.scala
new file mode 100644
index 000000000..960467293
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/internal_deps/A.scala
@@ -0,0 +1,10 @@
+package test_expect_failure.missing_direct_deps.internal_deps;
+
+object A {
+	def foo = {
+		B.foo
+		C.foo
+	}
+
+	def main = foo
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/internal_deps/B.scala b/test_expect_failure/missing_direct_deps/internal_deps/B.scala
new file mode 100644
index 000000000..8d0a7ea83
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/internal_deps/B.scala
@@ -0,0 +1,7 @@
+package test_expect_failure.missing_direct_deps.internal_deps;
+
+object B {
+	def foo = {
+		C.foo
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/internal_deps/BUILD b/test_expect_failure/missing_direct_deps/internal_deps/BUILD
new file mode 100644
index 000000000..0854bb49f
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/internal_deps/BUILD
@@ -0,0 +1,38 @@
+package(default_visibility = ["//visibility:public"])
+load("//scala:scala.bzl", "scala_library", "scala_test", "scala_binary")
+
+scala_library(
+    name="transitive_dependency_user",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],    
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="direct_dependency",
+    srcs=[
+        "B.scala",
+        ],
+    deps = ["transitive_dependency"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="transitive_dependency",
+    srcs=[
+        "C.scala",
+        ],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_binary(
+    name="user_binary",
+    main_class="A",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/internal_deps/C.scala b/test_expect_failure/missing_direct_deps/internal_deps/C.scala
new file mode 100644
index 000000000..739ab8a46
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/internal_deps/C.scala
@@ -0,0 +1,7 @@
+package test_expect_failure.missing_direct_deps.internal_deps;
+
+object C {
+	def foo = {
+		println("in C")
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/strict_disabled/A.scala b/test_expect_failure/missing_direct_deps/strict_disabled/A.scala
new file mode 100644
index 000000000..5a22b8214
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/strict_disabled/A.scala
@@ -0,0 +1,8 @@
+package test_expect_failure.missing_direct_deps.strict_disabled
+
+object A {
+	def foo = {
+		B.foo
+		C.foo
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/strict_disabled/B.scala b/test_expect_failure/missing_direct_deps/strict_disabled/B.scala
new file mode 100644
index 000000000..656b69a2d
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/strict_disabled/B.scala
@@ -0,0 +1,7 @@
+package test_expect_failure.missing_direct_deps.strict_disabled
+
+object B {
+	def foo = {
+		C.foo
+	}
+}
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/strict_disabled/BUILD b/test_expect_failure/missing_direct_deps/strict_disabled/BUILD
new file mode 100644
index 000000000..7a8fcc914
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/strict_disabled/BUILD
@@ -0,0 +1,28 @@
+package(default_visibility = ["//visibility:public"])
+load("//scala:scala.bzl", "scala_library", "scala_test")
+
+scala_library(
+    name="transitive_dependency_user",
+    srcs=[
+        "A.scala",
+        ],
+    deps = ["direct_dependency"],
+    dependency_analyzer_mode_soon_to_be_removed = "off"
+)
+
+scala_library(
+    name="direct_dependency",
+    srcs=[
+        "B.scala",
+        ],
+    deps = ["transitive_dependency"],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
+
+scala_library(
+    name="transitive_dependency",
+    srcs=[
+        "C.scala",
+        ],
+    dependency_analyzer_mode_soon_to_be_removed="error",
+)
\ No newline at end of file
diff --git a/test_expect_failure/missing_direct_deps/strict_disabled/C.scala b/test_expect_failure/missing_direct_deps/strict_disabled/C.scala
new file mode 100644
index 000000000..800a62b41
--- /dev/null
+++ b/test_expect_failure/missing_direct_deps/strict_disabled/C.scala
@@ -0,0 +1,7 @@
+package test_expect_failure.missing_direct_deps.strict_disabled
+
+object C {
+	def foo = {
+		println("in C")
+	}
+}
\ No newline at end of file
diff --git a/test_run.sh b/test_run.sh
index 4a12f3b01..1a8b15194 100755
--- a/test_run.sh
+++ b/test_run.sh
@@ -63,6 +63,118 @@ test_scala_library_suite() {
   action_should_fail build test_expect_failure/scala_library_suite:library_suite_dep_on_children
 }
 
+test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message() {
+  set +e
+
+  expected_message=$1
+  test_target=$2
+  operator=${3:-"eq"}
+
+  if [ "${operator}" = "eq" ]; then
+    error_message="bazel build of scala_library with missing direct deps should have failed."
+  else
+    error_message="bazel build of scala_library with missing direct deps should not have failed."
+  fi
+
+  command="bazel build ${test_target}"
+
+  output=$(${command} 2>&1)
+  status_code=$?
+
+  echo "$output"
+  if [ ${status_code} -${operator} 0 ]; then
+    echo ${error_message}
+    exit 1
+  fi
+
+  echo ${output} | grep "$expected_message"
+  if [ $? -ne 0 ]; then
+    echo "'bazel build ${test_target}' should have logged \"${expected_message}\"."
+        exit 1
+  fi
+
+  set -e
+}
+
+test_scala_library_expect_failure_on_missing_direct_deps_when_strict_is_disabled() {
+  expected_message="not found: value C"
+  test_target='test_expect_failure/missing_direct_deps/strict_disabled:transitive_dependency_user'
+
+  test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message "$expected_message" $test_target
+}
+
+test_scala_library_expect_failure_on_missing_direct_deps() {
+  dependenecy_target=$1
+  test_target=$2
+
+  local expected_messages="buildozer 'add deps $dependenecy_target' //$test_target"
+
+  test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message "${expected_message}" $test_target
+}
+
+test_scala_library_expect_failure_on_missing_direct_internal_deps() {
+  dependenecy_target='//test_expect_failure/missing_direct_deps/internal_deps:transitive_dependency'
+  test_target='test_expect_failure/missing_direct_deps/internal_deps:transitive_dependency_user'
+
+  test_scala_library_expect_failure_on_missing_direct_deps $dependenecy_target $test_target
+}
+
+test_scala_binary_expect_failure_on_missing_direct_deps() {
+  dependency_target='//test_expect_failure/missing_direct_deps/internal_deps:transitive_dependency'
+  test_target='test_expect_failure/missing_direct_deps/internal_deps:user_binary'
+
+  test_scala_library_expect_failure_on_missing_direct_deps ${dependency_target} ${test_target}
+}
+
+test_scala_library_expect_failure_on_missing_direct_external_deps_jar() {
+  dependenecy_target='@com_google_guava_guava_21_0//jar:jar'
+  test_target='test_expect_failure/missing_direct_deps/external_deps:transitive_external_dependency_user'
+
+  test_scala_library_expect_failure_on_missing_direct_deps $dependenecy_target $test_target
+}
+
+test_scala_library_expect_failure_on_missing_direct_external_deps_file_group() {
+  dependenecy_target='@com_google_guava_guava_21_0//jar:file'
+  test_target='test_expect_failure/missing_direct_deps/external_deps_file_group:transitive_external_dependency_user'
+
+  test_scala_library_expect_failure_on_missing_direct_deps $dependenecy_target $test_target
+}
+
+test_scala_library_expect_failure_on_missing_direct_deps_error_mode() {
+  dependenecy_target='//test_expect_failure/dep_analyzer_modes:transitive_dependency'
+  test_target='test_expect_failure/dep_analyzer_modes:error_mode'
+
+  expected_message="error: Target '$dependenecy_target' is used but isn't explicitly declared, please add it to the deps"
+
+  test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message "${expected_message}" ${test_target}
+}
+
+test_scala_library_expect_failure_on_missing_direct_deps_warn_mode() {
+  # warnings are cached. requires clean build...
+  bazel clean
+
+  dependenecy_target='//test_expect_failure/dep_analyzer_modes:transitive_dependency'
+  test_target='test_expect_failure/dep_analyzer_modes:warn_mode'
+
+  expected_message="warning: Target '$dependenecy_target' is used but isn't explicitly declared, please add it to the deps"
+
+  test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message "${expected_message}" ${test_target} "ne"
+}
+
+test_scala_library_expect_failure_on_missing_direct_deps_weird_mode() {
+  expected_message="Incorrect mode of dependency analyzer plugin! Mode must be 'error', 'warn' or 'off'."
+  test_target='test_expect_failure/dep_analyzer_modes:weird_mode'
+
+  test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message "${expected_message}" ${test_target}
+}
+
+test_scala_library_expect_failure_on_missing_direct_deps_off_mode() {
+  expected_message="test_expect_failure/dep_analyzer_modes/A.scala:[0-9+]: error: not found: value C"
+  test_target='test_expect_failure/dep_analyzer_modes:off_mode'
+
+  test_expect_failure_or_warning_on_missing_direct_deps_with_expected_message "${expected_message}" ${test_target}
+}
+
 test_scala_junit_test_can_fail() {
   action_should_fail test test_expect_failure/scala_junit_test:failing_test
 }
@@ -107,7 +219,7 @@ run_test_ci() {
     result=$?
     kill $pulse_printer_pid && wait $pulse_printer_pid 2>/dev/null || true
   } || return 1
-  
+
   DURATION=$SECONDS
   if [ $result -eq 0 ]; then
     echo -e "\n${GREEN}Test \"$TEST_ARG\" successful ($DURATION sec) $NC"
@@ -217,7 +329,7 @@ junit_generates_xml_logs() {
   else
     return 1
   fi
-  test -e 
+  test -e
 }
 
 test_junit_test_must_have_prefix_or_suffix() {
@@ -315,6 +427,37 @@ javac_jvm_flags_are_configured(){
   action_should_fail build //test_expect_failure/compilers_jvm_flags:can_configure_jvm_flags_for_javac
 }
 
+revert_internal_change() {
+  sed -i.bak "s/println(\"altered\")/println(\"orig\")/" $no_recompilation_path/C.scala
+  rm $no_recompilation_path/C.scala.bak
+}
+
+test_scala_library_expect_no_recompilation_on_internal_change_of_transitive_dependency() {
+  set +e
+  no_recompilation_path="test/src/main/scala/scala/test/strict_deps/no_recompilation"
+  build_command="bazel build //$no_recompilation_path/... --subcommands"
+
+  echo "running initial build"
+  $build_command
+  echo "changing internal behaviour of C.scala"
+  sed -i.bak "s/println(\"orig\")/println(\"altered\")/" ./$no_recompilation_path/C.scala
+
+  echo "running second build"
+  output=$(${build_command} 2>&1)
+
+  not_expected_recompiled_target="//$no_recompilation_path:transitive_dependency_user"
+
+  echo ${output} | grep "$not_expected_recompiled_target"
+  if [ $? -eq 0 ]; then
+    echo "bazel build was executed after change of internal behaviour of 'transitive_dependency' target. compilation of 'transitive_dependency_user' should not have been triggered."
+    revert_internal_change
+    exit 1
+  fi
+
+  revert_internal_change
+  set -e
+}
+
 if [ "$1" != "ci" ]; then
   runner="run_test_local"
 else
@@ -323,6 +466,7 @@ fi
 
 $runner bazel build test/...
 $runner bazel test test/...
+$runner bazel test third_party/...
 $runner bazel run test/src/main/scala/scala/test/twitter_scrooge:justscrooges
 $runner bazel run test:JavaBinary
 $runner bazel run test:JavaBinary2
@@ -354,3 +498,13 @@ $runner scala_test_test_filters
 $runner scala_junit_test_test_filter
 $runner scalac_jvm_flags_are_configured
 $runner javac_jvm_flags_are_configured
+$runner test_scala_library_expect_failure_on_missing_direct_internal_deps
+$runner test_scala_library_expect_failure_on_missing_direct_external_deps_jar
+$runner test_scala_library_expect_failure_on_missing_direct_external_deps_file_group
+$runner test_scala_library_expect_failure_on_missing_direct_deps_when_strict_is_disabled
+$runner test_scala_binary_expect_failure_on_missing_direct_deps
+$runner test_scala_library_expect_failure_on_missing_direct_deps_error_mode
+$runner test_scala_library_expect_failure_on_missing_direct_deps_warn_mode
+$runner test_scala_library_expect_failure_on_missing_direct_deps_weird_mode
+$runner test_scala_library_expect_failure_on_missing_direct_deps_off_mode
+$runner test_scala_library_expect_no_recompilation_on_internal_change_of_transitive_dependency
\ No newline at end of file
diff --git a/third_party/README.md b/third_party/README.md
new file mode 100644
index 000000000..54ee73139
--- /dev/null
+++ b/third_party/README.md
@@ -0,0 +1,5 @@
+This file lists license and version information of all code we did not author
+
+# dependency_analyzer 
+dependency_analyzer scala compiler plugin is based on [classpath-shrinker](https://github.com/scalacenter/classpath-shrinker) plugin.
+License: 3-clause revised BSD
\ No newline at end of file
diff --git a/third_party/plugin/LICENSE b/third_party/plugin/LICENSE
new file mode 100644
index 000000000..ec832b9a1
--- /dev/null
+++ b/third_party/plugin/LICENSE
@@ -0,0 +1,29 @@
+*******************************************************************************
+* Classpath Shrinker: a scalac plugin to detect unused classpath entries
+* Copyright (c) Scala Center
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions
+* are met:
+* 1. Redistributions of source code must retain the above copyright
+*    notice, this list of conditions and the following disclaimer.
+* 2. Redistributions in binary form must reproduce the above copyright
+*    notice, this list of conditions and the following disclaimer in the
+*    documentation and/or other materials provided with the distribution.
+* 3. Neither the name of the copyright holders nor the names of its
+*    contributors may be used to endorse or promote products derived from
+*    this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
+* THE POSSIBILITY OF SUCH DAMAGE.
+*******************************************************************************
\ No newline at end of file
diff --git a/third_party/plugin/src/main/BUILD b/third_party/plugin/src/main/BUILD
new file mode 100644
index 000000000..bd9b4ab36
--- /dev/null
+++ b/third_party/plugin/src/main/BUILD
@@ -0,0 +1,14 @@
+licenses(["notice"])  # 3-clause BSD
+
+load("//scala:scala.bzl", "scala_library", "scala_library_for_plugin_bootstrapping")
+
+scala_library_for_plugin_bootstrapping(
+    name = "dependency_analyzer",
+    srcs = ["io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzer.scala",
+            ],
+    resources = ["resources/scalac-plugin.xml"],
+    visibility = ["//visibility:public"],
+    deps = [
+        "//external:io_bazel_rules_scala/dependency/scala/scala_compiler"
+    ],
+)
\ No newline at end of file
diff --git a/third_party/plugin/src/main/io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzer.scala b/third_party/plugin/src/main/io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzer.scala
new file mode 100644
index 000000000..65144995f
--- /dev/null
+++ b/third_party/plugin/src/main/io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzer.scala
@@ -0,0 +1,110 @@
+package third_party.plugin.src.main.io.bazel.rulesscala.dependencyanalyzer
+
+import scala.reflect.io.AbstractFile
+import scala.tools.nsc.plugins.{Plugin, PluginComponent}
+import scala.tools.nsc.{Global, Phase}
+
+class DependencyAnalyzer(val global: Global) extends Plugin {
+
+  val name = "dependency-analyzer"
+  val description =
+    "Analyzes the used dependencies and fails the compilation " +
+      "if they are not explicitly used as direct dependencies (only declared transitively)"
+  val components = List[PluginComponent](Component)
+
+  var indirect: Map[String, String] = Map.empty
+  var direct: Set[String] = Set.empty
+  var analyzerMode: String = "error"
+  var currentTarget: String = "NA"
+
+  override def processOptions(options: List[String], error: (String) => Unit): Unit = {
+    var indirectJars: Seq[String] = Seq.empty
+    var indirectTargets: Seq[String] = Seq.empty
+
+    for (option <- options) {
+      option.split(":").toList match {
+        case "direct-jars" :: data => direct = data.toSet
+        case "indirect-jars" :: data => indirectJars = data;
+        case "indirect-targets" :: data => indirectTargets = data.map(_.replace(";", ":"))
+        case "current-target" :: target => currentTarget = target.map(_.replace(";", ":")).head
+        case "mode" :: mode => analyzerMode = mode.head
+        case unknown :: _ => error(s"unknown param $unknown")
+        case Nil =>
+      }
+    }
+    indirect = indirectJars.zip(indirectTargets).toMap
+  }
+
+
+  private object Component extends PluginComponent {
+    val global: DependencyAnalyzer.this.global.type =
+      DependencyAnalyzer.this.global
+
+    import global._
+
+    override val runsAfter = List("jvm")
+
+    val phaseName = DependencyAnalyzer.this.name
+
+    override def newPhase(prev: Phase): StdPhase = new StdPhase(prev) {
+      override def run(): Unit = {
+
+        super.run()
+
+        val usedJars = findUsedJars
+
+        warnOnIndirectTargetsFoundIn(usedJars)
+      }
+
+      private def warnOnIndirectTargetsFoundIn(usedJars: Set[AbstractFile]) = {
+        for (usedJar <- usedJars;
+             usedJarPath = usedJar.path;
+             target <- indirect.get(usedJarPath) if !direct.contains(usedJarPath)) {
+          val errorMessage =
+            s"""Target '$target' is used but isn't explicitly declared, please add it to the deps.
+               |You can use the following buildozer command:
+               |buildozer 'add deps $target' $currentTarget""".stripMargin
+
+          analyzerMode match {
+            case "error" => reporter.error(NoPosition, errorMessage)
+            case "warn" => reporter.warning(NoPosition, errorMessage)
+          }
+        }
+      }
+
+      override def apply(unit: CompilationUnit): Unit = ()
+    }
+
+  }
+
+  import global._
+
+  private def findUsedJars: Set[AbstractFile] = {
+    val jars = collection.mutable.Set[AbstractFile]()
+
+    def walkTopLevels(root: Symbol): Unit = {
+      def safeInfo(sym: Symbol): Type =
+        if (sym.hasRawInfo && sym.rawInfo.isComplete) sym.info else NoType
+
+      def packageClassOrSelf(sym: Symbol): Symbol =
+        if (sym.hasPackageFlag && !sym.isModuleClass) sym.moduleClass else sym
+
+      for (x <- safeInfo(packageClassOrSelf(root)).decls) {
+        if (x == root) ()
+        else if (x.hasPackageFlag) walkTopLevels(x)
+        else if (x.owner != root) { // exclude package class members
+          if (x.hasRawInfo && x.rawInfo.isComplete) {
+            val assocFile = x.associatedFile
+            if (assocFile.path.endsWith(".class") && assocFile.underlyingSource.isDefined)
+              assocFile.underlyingSource.foreach(jars += _)
+          }
+        }
+      }
+    }
+
+    exitingTyper {
+      walkTopLevels(RootClass)
+    }
+    jars.toSet
+  }
+}
diff --git a/third_party/plugin/src/main/resources/scalac-plugin.xml b/third_party/plugin/src/main/resources/scalac-plugin.xml
new file mode 100644
index 000000000..35b599afe
--- /dev/null
+++ b/third_party/plugin/src/main/resources/scalac-plugin.xml
@@ -0,0 +1,4 @@
+<plugin>
+  <name>dependency-analyzer</name>
+  <classname>third_party.plugin.src.main.io.bazel.rulesscala.dependencyanalyzer.DependencyAnalyzer</classname>
+</plugin>
\ No newline at end of file
diff --git a/third_party/plugin/src/test/BUILD b/third_party/plugin/src/test/BUILD
new file mode 100644
index 000000000..b5cbd69cb
--- /dev/null
+++ b/third_party/plugin/src/test/BUILD
@@ -0,0 +1,21 @@
+licenses(["notice"])  # 3-clause BSD
+
+load("//scala:scala.bzl", "scala_junit_test")
+
+scala_junit_test(
+        name = "dependency_analyzer_test",
+        srcs = ["io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzerTest.scala",
+                "io/bazel/rulesscala/dependencyanalyzer/TestUtil.scala"],
+        suffixes = ["Test"],
+        size = "small",
+        deps = ["//third_party/plugin/src/main:dependency_analyzer",
+                "//external:io_bazel_rules_scala/dependency/scala/scala_compiler",
+                "//external:io_bazel_rules_scala/dependency/scala/scala_library",
+                "@com_google_guava_guava_21_0//jar",
+                "@org_apache_commons_commons_lang_3_5//jar"
+                ],
+        jvm_flags = ["-Dplugin.jar.location=$(location //third_party/plugin/src/main:dependency_analyzer)",
+                     "-Dscala.library.location=$(location //external:io_bazel_rules_scala/dependency/scala/scala_library)",
+                     "-Dguava.jar.location=$(location @com_google_guava_guava_21_0//jar)",
+                     "-Dapache.commons.jar.location=$(location @org_apache_commons_commons_lang_3_5//jar)"],
+)
\ No newline at end of file
diff --git a/third_party/plugin/src/test/io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzerTest.scala b/third_party/plugin/src/test/io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzerTest.scala
new file mode 100644
index 000000000..0701fec9b
--- /dev/null
+++ b/third_party/plugin/src/test/io/bazel/rulesscala/dependencyanalyzer/DependencyAnalyzerTest.scala
@@ -0,0 +1,86 @@
+package third_party.plugin.src.test.io.bazel.rulesscala.dependencyanalyzer
+
+import TestUtil._
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(classOf[JUnit4])
+class DependencyAnalyzerTest {
+
+  @Test
+  def `error on indirect dependency target`(): Unit = {
+    val testCode =
+      """object Foo {
+        |  org.apache.commons.lang3.ArrayUtils.EMPTY_BOOLEAN_ARRAY.length
+        |}
+      """.stripMargin
+    val commonsTarget = "//commons:Target".encode()
+    val indirect = Map(apacheCommonsClasspath -> commonsTarget)
+    run(testCode, withIndirect = indirect).expectErrorOn(indirect(apacheCommonsClasspath).decoded)
+  }
+
+  @Test
+  def `error on multiple indirect dependency targets`(): Unit = {
+    val testCode =
+      """object Foo {
+        |  org.apache.commons.lang3.ArrayUtils.EMPTY_BOOLEAN_ARRAY.length
+        |  com.google.common.base.Strings.commonPrefix("abc", "abcd")
+        |}
+      """.stripMargin
+    val commonsTarget = "commonsTarget"
+
+    val guavaTarget = "guavaTarget"
+
+    val indirect = Map(apacheCommonsClasspath -> commonsTarget, guavaClasspath -> guavaTarget)
+    run(testCode, withIndirect = indirect).expectErrorOn(commonsTarget, guavaTarget)
+  }
+
+  @Test
+  def `do not give error on direct dependency target`(): Unit = {
+    val testCode =
+      """object Foo {
+        |  org.apache.commons.lang3.ArrayUtils.EMPTY_BOOLEAN_ARRAY.length
+        |}
+      """.stripMargin
+    val commonsTarget = "commonsTarget"
+
+    val direct = Seq(apacheCommonsClasspath)
+    val indirect = Map(apacheCommonsClasspath -> commonsTarget)
+    run(testCode, withDirect = direct, withIndirect = indirect).noErrorOn(commonsTarget)
+  }
+
+
+  implicit class `nice errors on sequence of strings`(infos: Seq[String]) {
+
+    private def checkErrorContainsMessage(target: String) = { info: String =>
+      info.contains(targetErrorMessage(target)) &
+        info.contains(buildozerCommand(target))
+    }
+
+    private def targetErrorMessage(target: String) =
+      s"Target '$target' is used but isn't explicitly declared, please add it to the deps"
+
+    private def buildozerCommand(depTarget: String) =
+      s"buildozer 'add deps $depTarget' $defaultTarget"
+
+    def expectErrorOn(targets: String*) = targets.foreach(target => assert(
+      infos.exists(checkErrorContainsMessage(target)),
+      s"expected an error on $target to appear in errors (with buildozer command)!")
+    )
+
+    def noErrorOn(target: String) = assert(
+      !infos.exists(checkErrorContainsMessage(target)),
+      s"error on $target should not appear in errors!")
+  }
+
+  implicit class `decode bazel labels`(targetLabel: String) {
+    def decoded() = {
+      targetLabel.replace(";", ":")
+    }
+
+    def encode() = {
+      targetLabel.replace(":", ";")
+    }
+  }
+}
diff --git a/third_party/plugin/src/test/io/bazel/rulesscala/dependencyanalyzer/TestUtil.scala b/third_party/plugin/src/test/io/bazel/rulesscala/dependencyanalyzer/TestUtil.scala
new file mode 100644
index 000000000..dd126e854
--- /dev/null
+++ b/third_party/plugin/src/test/io/bazel/rulesscala/dependencyanalyzer/TestUtil.scala
@@ -0,0 +1,92 @@
+package third_party.plugin.src.test.io.bazel.rulesscala.dependencyanalyzer
+
+import java.nio.file.Paths
+
+import scala.reflect.internal.util.BatchSourceFile
+import scala.reflect.io.VirtualDirectory
+import scala.tools.cmd.CommandLineParser
+import scala.tools.nsc.reporters.StoreReporter
+import scala.tools.nsc.{CompilerCommand, Global, Settings}
+
+object TestUtil {
+
+  import scala.language.postfixOps
+
+  final val defaultTarget = "//..."
+
+  def run(code: String, withDirect: Seq[String] = Seq.empty, withIndirect: Map[String, String] = Map.empty): Seq[String] = {
+    val compileOptions = Seq(
+      constructParam("direct-jars", withDirect),
+      constructParam("indirect-jars", withIndirect.keys),
+      constructParam("indirect-targets", withIndirect.values),
+      constructParam("current-target", Seq(defaultTarget))
+    ).mkString(" ")
+
+    val extraClasspath = withDirect ++ withIndirect.keys
+
+    val reporter: StoreReporter = runCompilation(code, compileOptions, extraClasspath)
+    reporter.infos.collect({ case msg if msg.severity == reporter.ERROR => msg.msg }).toSeq
+  }
+
+  private def runCompilation(code: String, compileOptions: String, extraClasspath: Seq[String]) = {
+    val fullClasspath: String = {
+      val extraClasspathString = extraClasspath.mkString(":")
+      if (toolboxClasspath.isEmpty) extraClasspathString
+      else s"$toolboxClasspath:$extraClasspathString"
+    }
+    val basicOptions =
+      createBasicCompileOptions(fullClasspath, toolboxPluginOptions)
+
+    eval(code, s"$basicOptions $compileOptions")
+  }
+
+  /** Evaluate using global instance instead of toolbox because toolbox seems
+    * to fail to typecheck code that comes from external dependencies. */
+  private def eval(code: String, compileOptions: String = ""): StoreReporter = {
+    // TODO: Optimize and cache global.
+    val options = CommandLineParser.tokenize(compileOptions)
+    val reporter = new StoreReporter()
+    val settings = new Settings(println)
+    val _ = new CompilerCommand(options, settings)
+    settings.outputDirs.setSingleOutput(new VirtualDirectory("(memory)", None))
+    val global = new Global(settings, reporter)
+    val run = new global.Run
+    val toCompile = new BatchSourceFile("<wrapper-init>", code)
+    run.compileSources(List(toCompile))
+    reporter
+  }
+
+  lazy val baseDir = System.getProperty("user.dir")
+
+  lazy val toolboxClasspath: String =
+    pathOf("scala.library.location")
+
+  lazy val toolboxPluginOptions: String = {
+    val jar = System.getProperty("plugin.jar.location")
+    val start= jar.indexOf("/third_party/plugin")
+    // this substring is needed due to issue: https://github.com/bazelbuild/bazel/issues/2475
+    val jarInRelationToBaseDir = jar.substring(start, jar.length)
+    val pluginPath = Paths.get(baseDir, jarInRelationToBaseDir).toAbsolutePath
+    s"-Xplugin:${pluginPath} -Jdummy=${pluginPath.toFile.lastModified}"
+  }
+
+  lazy val guavaClasspath: String =
+    pathOf("guava.jar.location")
+
+  lazy val apacheCommonsClasspath: String =
+    pathOf("apache.commons.jar.location")
+
+  private def pathOf(jvmFlag: String) = {
+    val jar = System.getProperty(jvmFlag)
+    val libPath = Paths.get(baseDir, jar).toAbsolutePath
+    libPath.toString
+  }
+
+  private def createBasicCompileOptions(classpath: String, usePluginOptions: String) =
+    s"-classpath $classpath $usePluginOptions"
+
+  private def constructParam(name: String, values: Iterable[String]) = {
+    if (values.isEmpty) ""
+    else s"-P:dependency-analyzer:$name:${values.mkString(":")}"
+  }
+}