Fix CppLibrary::vendor_bundle? to use "bundle show" paths intead of assuming vendor/bundle

Author: ianfixes

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Fixed
 - Library installation no longer "fails" if the library is already installed
 - Platform definition for `mega2560` now includes proper AVR compiler flag
+- `CppLibrary::vendor_bundle?` now asks where gems are, instead of assuming `vendor/bundle/`
 
 ### Security
 

lib/arduino_ci/cpp_library.rb

@@ -32,6 +32,9 @@ class CppLibrary
     # @return [String] the last command
     attr_reader :last_cmd
 
+    # @return [Array<Pathname>] Directories suspected of being vendor-bundle
+    attr_reader :vendor_bundle_cache
+
     # @param base_dir [Pathname] The path to the library being tested
     # @param arduino_lib_dir [Pathname] The path to the libraries directory
     def initialize(base_dir, arduino_lib_dir)
@@ -45,26 +48,57 @@ def initialize(base_dir, arduino_lib_dir)
       @last_out = ""
       @last_msg = ""
       @has_libasan_cache = {}
+      @vendor_bundle_cache = nil
     end
 
     # Guess whether a file is part of the vendor bundle (indicating we should ignore it).
     #
-    # This assumes the vendor bundle will be at `vendor/bundle` and not some other location
+    # A safe way to do this seems to be to check whether any of the installed gems
+    #   appear to be a subdirectory of (but not equal to) the working directory.
+    #   That gets us the vendor directory (or multiple directories). We can check
+    #   if the given path is contained by any of those.
+    #
     # @param path [Pathname] The path to check
     # @return [bool]
     def vendor_bundle?(path)
-      # TODO: look for Gemfile, look for .bundle/config and get BUNDLE_PATH from there?
-      base = @base_dir + "vendor"
-      return false unless base.exist?
+      # use a cache to be kind to the filesystem
+      if @vendor_bundle_cache == false
+        # no bundle
+        return false
+      elsif @vendor_bundle_cache.nil?
+        # if the bundle show command fails, assume there isn't a bundle
+        bundle_info = Host.run_and_capture("bundle show --paths")
+        unless bundle_info[:success]
+          @vendor_bundle_cache = false
+          return false
+        end
 
-      vendor_bundle_aliases = [base, base.realpath]
+        # by preemptively switching to the parent directory, we can both ensure that
+        # we miss any gems that are equal to the working directory AND exploit some
+        # commonality in the paths to cut down our search locations
+        #
+        # NOT REJECTING THE WORKING DIRECTORY IS SUPER IMPORTANT because if we do,
+        # we won't be able to run CI on this library itself.
+        bundle_paths = bundle_info[:out].lines
+                                        .map { |l| Pathname.new(l.chomp) }
+                                        .select(&:exist?)
+                                        .map(&:realpath)
+                                        .map(&:parent)
+                                        .uniq
+        wd = Pathname.new(".").realpath
+        @vendor_bundle_cache = bundle_paths.select do |gem_path|
+          gem_path.ascend do |part|
+            break true if wd == part
+          end
+        end
+      end
 
-      # we could do this but some rubies don't return an enumerator for ascend
-      # path.ascend.any? { |part| vendor_bundle_aliases.include?(part) }
-      path.ascend do |part|
-        return true if vendor_bundle_aliases.include?(part)
+      # With vendor bundles located, check this file against those
+      @vendor_bundle_cache.any? do |gem_path|
+        path.ascend do |part|
+          break true if gem_path == part
+        end
       end
-      false
     end
 
     # Guess whether a file is part of the tests/ dir (indicating library compilation should ignore it).