set working directory to cwd by default (#8)

* set working directory to cwd by default

* add flag to skip output when there are no results

.github/workflows/bazel-ci.yaml

@@ -28,21 +28,19 @@ jobs:
       # need to bootstrap
       - name: build
         run: bazel build //cli:bazel-differ
+      - name: set bazel differ path
+        run: echo "BAZEL_DIFFER=$(bazel info bazel-bin)/cli/bazel-differ_/bazel-differ" >> $GITHUB_ENV
       # This section starts an example of how to use get-targets in your CI process
       - name: Get revisions
         id: get-revisions
         run: GITHUB_TOKEN=${{ secrets.GITHUB_TOKEN  }} ./tools/diff-sha.sh
       - name: get-test-targets
-        run: |
-          $(bazel info bazel-bin)/cli/bazel-differ_/bazel-differ get-targets -w $(pwd) -s ${{ steps.get-revisions.outputs.previous_sha }} -f ${{ steps.get-revisions.outputs.current_sha }} -o test_targets.txt
-          bash -c '[[ ! -s test_targets.txt ]] && rm test_targets.txt || true'
+        run: $BAZEL_DIFFER get-targets -s ${{ steps.get-revisions.outputs.previous_sha }} -f ${{ steps.get-revisions.outputs.current_sha }} -o test_targets.txt -v --output-on-empty=false
       - name: run-test-targets
         if: hashFiles('test_targets.txt') != ''
         run: bazel test --target_pattern_file=test_targets.txt
       - name: get-build-targets
-        run: |
-          $(bazel info bazel-bin)/cli/bazel-differ_/bazel-differ get-targets -w $(pwd) -s ${{ steps.get-revisions.outputs.previous_sha }} -f ${{ steps.get-revisions.outputs.current_sha }} -o build_targets.txt -v
-          bash -c '[[ ! -s build_targets.txt ]] && rm build_targets.txt || true'
+        run: $BAZEL_DIFFER get-targets -s ${{ steps.get-revisions.outputs.previous_sha }} -f ${{ steps.get-revisions.outputs.current_sha }} -o build_targets.txt -v --output-on-empty=false
       - name: run-build-targets
         if: hashFiles('build_targets.txt') != ''
         run: bazel build --target_pattern_file=build_targets.txt

cmd/get_targets.go

@@ -13,6 +13,7 @@ var finalRevision string
 var query string
 var cacheDir string
 var cacheDisabled bool
+var outputOnEmpty bool
 
 // getTargets represents the get-targets command
 var getTargets = &cobra.Command{
@@ -43,6 +44,9 @@ $ bazel-differ get-targets -w path/to/workspace -b $(which bazel) -s START_HASH
 		targetNames := targetHasher.GetNames(queriedTargets)
 
 		if Output != "" {
+			if len(targetNames) == 0 && !outputOnEmpty {
+				return
+			}
 			internal.WriteTargetsFile(targetNames, Output)
 		}
 
@@ -66,10 +70,11 @@ func getHashes(revision string, gitClient internal.GitClient, cacheManager cache
 
 	hashes, err := cacheManager.Get(context.Background(), revision)
 	ExitIfError(err, fmt.Sprintf("Error retrieving hashes for revision %s from cache", revision))
-
-	if hashes == nil {
-		hashes, err = targetHasher.HashAllBazelTargetsAndSourcefiles(seedfilePaths)
+	if hashes != nil {
+		return hashes
 	}
+
+	hashes, err = targetHasher.HashAllBazelTargetsAndSourcefiles(seedfilePaths)
 	ExitIfError(err, "")
 
 	err = cacheManager.Put(context.Background(), revision, hashes)
@@ -92,6 +97,8 @@ func init() {
 	getTargets.PersistentFlags().StringVarP(&Output, "output", "o", "",
 		"Filepath to write the impacted Bazel targets to, "+
 			"newline separated")
+	getTargets.PersistentFlags().BoolVar(&outputOnEmpty, "output-on-empty", true,
+		"Sets whether to write a file output when there are no results; useful for skipping targets in CI")
 	getTargets.PersistentFlags().StringVar(&cacheDir, "cache-dir", "",
 		"Directory to cache hashes associated with commits")
 	getTargets.PersistentFlags().BoolVar(&cacheDisabled, "nocache", false,

cmd/root.go

@@ -25,6 +25,11 @@ var rootCmd = &cobra.Command{
 }
 
 func init() {
+	cwd, err := os.Getwd()
+	if err != nil {
+		panic(err)
+	}
+	WorkspacePath = cwd
 	rootCmd.PersistentFlags().StringVarP(&WorkspacePath, "workspacePath", "w", "", "Path to Bazel workspace directory.")
 	rootCmd.PersistentFlags().StringVarP(&BazelPath, "bazelPath", "b", "", "Path to Bazel binary")
 	rootCmd.PersistentFlags().StringVarP(&BazelStartupOptions, "bazelStartupOptions", "y", "",