Fix misleading error message when CODEOWNERS is out of date (#164)

* Fix misleading error message when CODEOWNERS is out of date

When running `codeownership validate --skip-autocorrect` with an
out-of-date CODEOWNERS file, the error from codeowners-rs says to run
`codeowners generate`, which is the standalone Rust CLI and not
available to users of this gem. Rewrite the message to point to
`bin/codeownership validate` instead.

Fixes #155

* Replace Ruby-level error rewrite with fix at source in codeowners-rs

Instead of rescuing RuntimeError in validate! and doing a fragile
gsub on the error message string, pass executable_name to RunConfig
so codeowners-rs generates the correct message directly.

This requires a companion change in codeowners-rs that changes
executable_name to hold the full command (e.g. "codeowners generate")
rather than just the binary name, so the format string no longer
hardcodes the " generate" subcommand.

* Add spec for validate! error message referencing bin/codeownership validate

Verifies that when CODEOWNERS is out of date and validate! is called with
autocorrect: false, the error message references bin/codeownership validate
rather than the standalone codeowners generate CLI command.

Author: dduugg

ext/code_ownership/src/lib.rs

@@ -116,7 +116,7 @@ fn build_run_config() -> RunConfig {
         codeowners_file_path: None,
         config_path,
         no_cache: false,
-        executable_name: None,
+        executable_name: Some("bin/codeownership validate".to_string()),
     }
 }
 

lib/code_ownership/code_ownership.bundle

@@ -555,4 +555,28 @@
       end
     end
   end
+
+  describe '.validate!' do
+    context 'when the CODEOWNERS file is out of date' do
+      before do
+        create_non_empty_application
+        RustCodeOwners.generate_and_validate(nil, false)
+        # Add a new annotated file to make the CODEOWNERS file out of date
+        write_file('packs/my_pack/new_file.rb', "# @team Bar\nclass NewFile; end\n")
+      end
+
+      it 'raises an error referencing bin/codeownership validate' do
+        expect { CodeOwnership.validate!(autocorrect: false) }.to raise_error(
+          RuntimeError,
+          /Run `bin\/codeownership validate/
+        )
+      end
+
+      it 'does not reference the standalone codeowners CLI' do
+        expect { CodeOwnership.validate!(autocorrect: false) }.to raise_error(RuntimeError) do |error|
+          expect(error.message).not_to include('`codeowners generate`')
+        end
+      end
+    end
+  end
 end