A bit of starlark micro-optimization (#4468)

**What type of PR is this?**
Cleanup/perf improvement

**What does this PR do? Why is it needed?**

**Which issues(s) does this PR fix?**

Fixes #

**Other notes for review**

Author: dzbarsky

go/private/common.bzl

@@ -155,16 +155,6 @@ def get_versioned_shared_lib_extension(path):
 
 MINIMUM_BAZEL_VERSION = "6.5.0"
 
-def as_list(v):
-    """Returns a list, tuple, or depset as a list."""
-    if type(v) == "list":
-        return v
-    if type(v) == "tuple":
-        return list(v)
-    if type(v) == "depset":
-        return v.to_list()
-    fail("as_list failed on {}".format(v))
-
 def as_iterable(v):
     """Returns a list, tuple, or depset as something iterable."""
     if type(v) == "list":

go/private/context.bzl

@@ -316,6 +316,7 @@ def new_go_info(
     srcs = attr_srcs + generated_srcs
     embedsrcs = [f for t in getattr(attr, "embedsrcs", []) for f in as_iterable(t.files)]
     deps = [get_archive(dep) for dep in getattr(attr, "deps", [])]
+    data = getattr(attr, "data", [])
 
     go_info = {
         "name": go.label.name if not name else name,
@@ -333,7 +334,7 @@ def new_go_info(
         "x_defs": {},
         "deps": deps,
         "gc_goopts": _expand_opts(go, "gc_goopts", getattr(attr, "gc_goopts", [])),
-        "runfiles": _collect_runfiles(go, getattr(attr, "data", []), deps),
+        "runfiles": _collect_runfiles(go, data, deps),
         "cgo": getattr(attr, "cgo", False),
         "cdeps": getattr(attr, "cdeps", []),
         "cppopts": _expand_opts(go, "cppopts", getattr(attr, "cppopts", [])),
@@ -351,11 +352,13 @@ def new_go_info(
     x_defs = go_info["x_defs"]
 
     for k, v in getattr(attr, "x_defs", {}).items():
-        v = _expand_location(go, attr, v)
+        if "$" in v:
+            v = go._ctx.expand_location(v, data)
         if "." not in k:
-            k = "{}.{}".format(importmap, k)
+            k = "%s.%s" % (importmap, k)
         x_defs[k] = v
     go_info["x_defs"] = x_defs
+
     if not go_info["cgo"]:
         for k in ("cdeps", "cppopts", "copts", "cxxopts", "clinkopts"):
             if getattr(attr, k, None):
@@ -1070,6 +1073,3 @@ go_config = rule(
 
 def _expand_opts(go, attribute_name, opts):
     return [go._ctx.expand_make_variables(attribute_name, opt, {}) for opt in opts]
-
-def _expand_location(go, attr, s):
-    return go._ctx.expand_location(s, getattr(attr, "data", []))

go/private/rules/binary.bzl

@@ -171,7 +171,7 @@ def _go_binary_impl(ctx):
     if go.mode.linkmode in LINKMODES_EXECUTABLE:
         env = {}
         for k, v in ctx.attr.env.items():
-            env[k] = ctx.expand_location(v, ctx.attr.data)
+            env[k] = ctx.expand_location(v, ctx.attr.data) if "$" in v else v
         providers.append(RunEnvironmentInfo(environment = env))
 
         # The executable is automatically added to the runfiles.

go/private/rules/test.bzl

@@ -21,7 +21,6 @@ load(
     "GO_TOOLCHAIN",
     "GO_TOOLCHAIN_LABEL",
     "SUPPORTS_PATH_MAPPING_REQUIREMENT",
-    "as_list",
     "asm_exts",
     "cgo_exts",
     "go_exts",
@@ -202,7 +201,7 @@ def _go_test_impl(ctx):
         "GO_TEST_RUN_FROM_BAZEL": "1",
     }
     for k, v in ctx.attr.env.items():
-        env[k] = ctx.expand_location(v, ctx.attr.data)
+        env[k] = ctx.expand_location(v, ctx.attr.data) if "$" in v else v
 
     run_environment_info = RunEnvironmentInfo(env, ctx.attr.env_inherit)
 
@@ -708,19 +707,19 @@ def _recompile_external_deps(go, external_go_info, internal_archive, library_lab
             testfilter = None,
             is_main = False,
             mode = go.mode,
-            srcs = as_list(arc_data.srcs),
+            srcs = list(arc_data.srcs),
             cover = arc_data._cover,
-            embedsrcs = as_list(arc_data._embedsrcs),
+            embedsrcs = list(arc_data._embedsrcs),
             x_defs = dict(arc_data._x_defs),
             deps = deps,
-            gc_goopts = as_list(arc_data._gc_goopts),
+            gc_goopts = list(arc_data._gc_goopts),
             runfiles = arc_data.runfiles,
             cgo = arc_data._cgo,
-            cdeps = as_list(arc_data._cdeps),
-            cppopts = as_list(arc_data._cppopts),
-            copts = as_list(arc_data._copts),
-            cxxopts = as_list(arc_data._cxxopts),
-            clinkopts = as_list(arc_data._clinkopts),
+            cdeps = list(arc_data._cdeps),
+            cppopts = list(arc_data._cppopts),
+            copts = list(arc_data._copts),
+            cxxopts = list(arc_data._cxxopts),
+            clinkopts = list(arc_data._clinkopts),
         )
 
         # If this archive needs to be recompiled, use go.archive.