Add error message if protofile is attempted to be read or written fro…

…m stdio (#2095)

private/buf/buffetch/internal/errors.go

@@ -111,6 +111,14 @@ func NewInvalidPathError(format string, path string) error {
 	return fmt.Errorf("invalid %spath: %q", format, path)
 }
 
+// NewProtoFileCannotBeDevPathError is a fetch error.
+func NewProtoFileCannotBeDevPathError(format string, path string) error {
+	if format != "" {
+		format = format + " "
+	}
+	return fmt.Errorf("invalid %spath: %q (protofiles cannot be read or written to or from stdio)", format, path)
+}
+
 // NewRealCleanPathError is a fetch error.
 func NewRealCleanPathError(path string) error {
 	return fmt.Errorf("could not clean relative path %q", path)

private/buf/buffetch/internal/proto_file_ref.go

@@ -14,6 +14,8 @@
 
 package internal
 
+import "github.com/bufbuild/buf/private/pkg/app"
+
 var (
 	_ ParsedProtoFileRef = &protoFileRef{}
 )
@@ -24,12 +26,15 @@ type protoFileRef struct {
 	includePackageFiles bool
 }
 
-func newProtoFileRef(format string, path string, includePackageFiles bool) *protoFileRef {
+func newProtoFileRef(format string, path string, includePackageFiles bool) (*protoFileRef, error) {
+	if app.IsDevPath(path) || path == "-" {
+		return nil, NewProtoFileCannotBeDevPathError(format, path)
+	}
 	return &protoFileRef{
 		format:              format,
 		path:                path,
 		includePackageFiles: includePackageFiles,
-	}
+	}, nil
 }
 
 func (s *protoFileRef) Format() string {

private/buf/buffetch/internal/ref_parser.go

@@ -94,7 +94,7 @@ func (a *refParser) getParsedRef(
 		return getArchiveRef(rawRef, archiveFormatInfo.archiveType, archiveFormatInfo.defaultCompressionType)
 	}
 	if protoFileOK {
-		return getProtoFileRef(rawRef), nil
+		return getProtoFileRef(rawRef)
 	}
 	if dirOK {
 		return getDirRef(rawRef)
@@ -342,7 +342,7 @@ func getGitRefName(path string, branch string, tag string, ref string) (git.Name
 	return git.NewTagName(tag), nil
 }
 
-func getProtoFileRef(rawRef *RawRef) ParsedProtoFileRef {
+func getProtoFileRef(rawRef *RawRef) (ParsedProtoFileRef, error) {
 	return newProtoFileRef(
 		rawRef.Format,
 		rawRef.Path,

private/buf/bufwire/image_config_reader.go

@@ -290,6 +290,9 @@ func filterImageConfigs(imageConfigs []ImageConfig, protoFileRef buffetch.ProtoF
 		}
 		images = append(images, imageConfig.Image())
 	}
+	if path == "" {
+		return nil, errors.New("did not find a matching image file for the ProtoFileRef")
+	}
 	image, err := bufimage.MergeImages(images...)
 	if err != nil {
 		return nil, err

private/pkg/app/app.go

@@ -291,6 +291,12 @@ func IsDevNull(path string) bool {
 	return path != "" && path == DevNullFilePath
 }
 
+// IsDevPath returns true if the path is the equivalent of /dev/stdin, /dev/stdout,
+// /dev/stderr, or /dev/null.
+func IsDevPath(path string) bool {
+	return IsDevStdin(path) || IsDevStdout(path) || IsDevStderr(path) || IsDevNull(path)
+}
+
 // Main runs the application using the OS Container and calling os.Exit on the return value of Run.
 func Main(ctx context.Context, f func(context.Context, Container) error) {
 	container, err := NewContainerForOS()