fix(files): 编辑器保存和打开也逐跳核对 SHA-256，途中变了的内容不写盘也不打开

cmd/felis/files.go

@@ -47,7 +47,7 @@ func cmdFiles(args []string, stdout, stderr io.Writer) int {
 	to := fs.String("to", "", "rename only: the destination path")
 	sourceURL := fs.String("source-url", "", "upload only: felis-api URL to fetch the bytes from")
 	size := fs.Int64("size", -1, "upload only: the byte count the fetched file must have")
-	sum := fs.String("sha256", "", "upload only: the SHA-256 (hex) the fetched file must have")
+	sum := fs.String("sha256", "", "write and upload: the SHA-256 (hex) the content or the fetched file must have")
 	overwrite := fs.Bool("overwrite", false, "upload and unzip: replace files already there")
 	if err := fs.Parse(args); err != nil {
 		return 2
@@ -70,12 +70,18 @@ func cmdFiles(args []string, stdout, stderr io.Writer) int {
 	// channel that must be a valid string.
 	switch *op {
 	case fileedit.OpWrite:
+		// The content's SHA-256 comes with it, so bytes that changed on the way
+		// to this Job are refused rather than written (Request.ContentSHA256).
+		if *sum == "" {
+			fmt.Fprintln(stderr, "felis files: a write needs --sha256")
+			return 2
+		}
 		content, err := fileedit.ContentFromEnv(os.LookupEnv)
 		if err != nil {
 			fmt.Fprintf(stderr, "felis files: %v\n", err)
 			return 2
 		}
-		req.Content = content
+		req.Content, req.ContentSHA256 = content, *sum
 	case fileedit.OpUpload:
 		token := os.Getenv(fileedit.UploadTokenEnv)
 		if *sourceURL == "" || token == "" {

cmd/felis/files_test.go

@@ -238,10 +238,11 @@ func TestCmdFilesUpload(t *testing.T) {
 
 func TestCmdFilesWrite(t *testing.T) {
 	root := t.TempDir()
-	args := []string{"--op", "write", "--path", "ops.json", "--worlds-root", root}
+	content := []byte("[]\r\n")
+	sum := sha256.Sum256(content)
+	args := []string{"--op", "write", "--path", "ops.json", "--worlds-root", root, "--sha256", hex.EncodeToString(sum[:])}
 
 	t.Run("reassembles the content parts", func(t *testing.T) {
-		content := []byte("[]\r\n")
 		t.Setenv(fileedit.ContentPartsEnv, "1")
 		t.Setenv(fileedit.ContentEnv+"_0", base64.StdEncoding.EncodeToString(content))
 		var stdout, stderr bytes.Buffer
@@ -261,13 +262,42 @@ func TestCmdFilesWrite(t *testing.T) {
 		t.Setenv(fileedit.ContentPartsEnv, "2")
 		t.Setenv(fileedit.ContentEnv+"_0", base64.StdEncoding.EncodeToString([]byte("x")))
 		var stdout, stderr bytes.Buffer
-		if code := cmdFiles([]string{"--op", "write", "--path", "new.txt", "--worlds-root", root}, &stdout, &stderr); code != 2 {
+		if code := cmdFiles([]string{"--op", "write", "--path", "new.txt", "--worlds-root", root, "--sha256", hex.EncodeToString(sum[:])}, &stdout, &stderr); code != 2 {
 			t.Fatalf("exit %d, want 2", code)
 		}
 		if _, err := os.Lstat(filepath.Join(root, "new.txt")); !os.IsNotExist(err) {
 			t.Fatalf("an incomplete spec wrote a file: %v", err)
 		}
 	})
+
+	// Without the content's SHA-256 the Job could not tell bytes changed on the
+	// way from the bytes felis-api sent.
+	t.Run("a write without its SHA-256 exits 2 and writes nothing", func(t *testing.T) {
+		t.Setenv(fileedit.ContentPartsEnv, "1")
+		t.Setenv(fileedit.ContentEnv+"_0", base64.StdEncoding.EncodeToString(content))
+		var stdout, stderr bytes.Buffer
+		if code := cmdFiles([]string{"--op", "write", "--path", "new.txt", "--worlds-root", root}, &stdout, &stderr); code != 2 {
+			t.Fatalf("exit %d, want 2", code)
+		}
+		if _, err := os.Lstat(filepath.Join(root, "new.txt")); !os.IsNotExist(err) {
+			t.Fatalf("a write without its SHA-256 wrote a file: %v", err)
+		}
+	})
+
+	t.Run("content that changed on the way is a result and writes nothing", func(t *testing.T) {
+		t.Setenv(fileedit.ContentPartsEnv, "1")
+		t.Setenv(fileedit.ContentEnv+"_0", base64.StdEncoding.EncodeToString([]byte("[]\n")))
+		var stdout, stderr bytes.Buffer
+		if code := cmdFiles([]string{"--op", "write", "--path", "new.txt", "--worlds-root", root, "--sha256", hex.EncodeToString(sum[:])}, &stdout, &stderr); code != 0 {
+			t.Fatalf("exit %d, stderr %q", code, stderr.String())
+		}
+		if res := filesResult(t, stdout.String()); res.Code != fileedit.CodeDigestMismatch {
+			t.Fatalf("result = %+v, want %s", res, fileedit.CodeDigestMismatch)
+		}
+		if _, err := os.Lstat(filepath.Join(root, "new.txt")); !os.IsNotExist(err) {
+			t.Fatalf("changed content wrote a file: %v", err)
+		}
+	})
 }
 
 // A caller-fault outcome is a successful run carrying a code, so felis-api can