Go modules: raise GitDependenciesNotReachable

go_modules/lib/dependabot/go_modules/file_parser.rb

@@ -139,8 +139,9 @@ def go_mod_content
       def handle_parser_error(path, stderr)
         case stderr
         when /go: .*: unknown revision/m
-          line = stderr.lines.grep(/unknown revision/).first
-          raise Dependabot::DependencyFileNotResolvable, line.strip
+          line = stderr.lines.grep(/unknown revision/).first.strip
+          handle_github_unknown_revision(line) if line.start_with?("go: github.com/")
+          raise Dependabot::DependencyFileNotResolvable, line
         when /go: .*: unrecognized import path/m
           line = stderr.lines.grep(/unrecognized import/).first
           raise Dependabot::DependencyFileNotResolvable, line.strip
@@ -156,6 +157,26 @@ def handle_parser_error(path, stderr)
         end
       end
 
+      GITHUB_REPO_REGEX = %r{github.com/[^@]*}.freeze
+      def handle_github_unknown_revision(line)
+        repo_path = line.scan(GITHUB_REPO_REGEX).first
+        return unless repo_path
+
+        # Query for _any_ version of this module, to know if it doesn't exist (or is private)
+        # or we were just given a bad revision by this manifest
+        SharedHelpers.in_a_temporary_directory do
+          SharedHelpers.with_git_configured(credentials: credentials) do
+            File.write("go.mod", "module dummy\n")
+
+            env = { "GOPRIVATE" => "*" }
+            _, _, status = Open3.capture3(env, SharedHelpers.escape_command("go get #{repo_path}"))
+            raise Dependabot::DependencyFileNotResolvable, line if status.success?
+
+            raise Dependabot::GitDependenciesNotReachable, [repo_path]
+          end
+        end
+      end
+
       def rev_identifier?(dep)
         dep["Version"]&.match?(GIT_VERSION_REGEX)
       end

go_modules/spec/dependabot/go_modules/file_parser_spec.rb

@@ -150,6 +150,33 @@
       end
     end
 
+    describe "a non-existent github.com repository" do
+      let(:invalid_repo) { "github.com/dependabot-fixtures/must-never-exist" }
+      let(:go_mod_content) do
+        go_mod = fixture("go_mods", go_mod_fixture_name)
+        go_mod.sub("rsc.io/quote", invalid_repo)
+      end
+
+      it "raises the correct error" do
+        expect { parser.parse }.
+          to raise_error(Dependabot::GitDependenciesNotReachable) do |error|
+            expect(error.dependency_urls).to contain_exactly(invalid_repo)
+          end
+      end
+    end
+
+    describe "a non-existent github.com revision" do
+      let(:go_mod_content) do
+        go_mod = fixture("go_mods", go_mod_fixture_name)
+        go_mod.sub("github.com/mattn/go-colorable v0.0.9", "github.com/mattn/go-colorable v0.1234.4321")
+      end
+
+      it "raises the correct error" do
+        expect { parser.parse }.
+          to raise_error(Dependabot::DependencyFileNotResolvable)
+      end
+    end
+
     describe "a non-existing transitive dependency" do
       # go.mod references repo with bad go.mod, a broken transitive dependency
       let(:go_mod_fixture_name) { "parent_module.mod" }