Merge "Handle empty input file case in Metadata generation" into main am: d5e2717e27

Original change: https://android-review.googlesource.com/c/platform/build/+/2835510

Change-Id: Iafefabdfdbe8557f1ffade6dd1f96f3415e0d9d5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

tools/metadata/generator.go

@@ -73,6 +73,20 @@ func readFileToString(filePath string) string {
 	return string(data)
 }
 
+func writeNewlineToOutputFile(outputFile string) {
+	file, err := os.Create(outputFile)
+	data := "\n"
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer file.Close()
+
+	_, err = file.Write([]byte(data))
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
 func processTestSpecProtobuf(
 	filePath string, ownershipMetadataMap *sync.Map, keyLocks *keyToLocksMap,
 	errCh chan error, wg *sync.WaitGroup,
@@ -140,6 +154,10 @@ func main() {
 
 	inputFileData := strings.TrimRight(readFileToString(*inputFile), "\n")
 	filePaths := strings.Split(inputFileData, "\n")
+	if len(filePaths) == 1 && filePaths[0] == "" {
+		writeNewlineToOutputFile(*outputFile)
+		return
+	}
 	ownershipMetadataMap := &sync.Map{}
 	keyLocks := &keyToLocksMap{}
 	errCh := make(chan error, len(filePaths))

tools/metadata/testdata/emptyInputFile.txt

@@ -0,0 +1 @@
+

tools/metadata/testdata/generatedEmptyOutputFile.txt

@@ -0,0 +1 @@
+

tools/metadata/testdata/metadata_test.go

@@ -63,3 +63,27 @@ func TestMetadataNegativeCase(t *testing.T) {
 		)
 	}
 }
+
+func TestEmptyInputFile(t *testing.T) {
+	cmd := exec.Command(
+		"metadata", "-rule", "test_spec", "-inputFile", "./emptyInputFile.txt", "-outputFile",
+		"./generatedEmptyOutputFile.txt",
+	)
+	stderr, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("Error running metadata command: %s. Error: %v", stderr, err)
+	}
+
+	// Read the contents of the generated output file
+	generatedOutput, err := ioutil.ReadFile("./generatedEmptyOutputFile.txt")
+	if err != nil {
+		t.Fatalf("Error reading generated output file: %s", err)
+	}
+
+	fmt.Println()
+
+	// Compare the contents
+	if string(generatedOutput) != "\n" {
+		t.Errorf("Generated file contents do not match the expected output")
+	}
+}