cmd/shfmt: add -filename to name standard input

Otherwise, EditorConfig support is pretty useless with stdin, as we
would always use "<standard input>" as the filename.

This feature is particularly useful for editor integrations, which want
to format a real file on disk but with the in-memory contents that the
user is editing.

Start writing the changelog for 3.2.0 too.

Fixes #577.

CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+- **cmd/shfmt**
+  - Add `-filename` to give a name to standard input
+- **syntax**
+  - Rewrite arithmetic parsing to fix operator precedence
+
 ## [3.1.1] - 2020-05-04
 
 - **cmd/shfmt**

cmd/shfmt/main.go

@@ -38,8 +38,9 @@ var (
 	// useEditorConfig will be false if any parser or printer flags were used.
 	useEditorConfig = true
 
-	langStr = flag.String("ln", "", "")
-	posix   = flag.Bool("p", false, "")
+	langStr  = flag.String("ln", "", "")
+	posix    = flag.Bool("p", false, "")
+	filename = flag.String("filename", "", "")
 
 	indent      = flag.Uint("i", 0, "")
 	binNext     = flag.Bool("bn", false, "")
@@ -85,8 +86,9 @@ for shell files - both by filename extension and by shebang.
 
 Parser options:
 
-  -ln str   language variant to parse (bash/posix/mksh, default "bash")
-  -p        shorthand for -ln=posix
+  -ln str        language variant to parse (bash/posix/mksh, default "bash")
+  -p             shorthand for -ln=posix
+  -filename str  provide a name for the standard input file
 
 Printer options:
 
@@ -170,16 +172,24 @@ Utilities:
 		color = true
 	}
 	if flag.NArg() == 0 || (flag.NArg() == 1 && flag.Arg(0) == "-") {
-		if err := formatStdin(); err != nil {
+		name := "<standard input>"
+		if *filename != "" {
+			name = *filename
+		}
+		if err := formatStdin(name); err != nil {
 			if err != errChangedWithDiff {
 				fmt.Fprintln(os.Stderr, err)
 			}
 			return 1
 		}
 		return 0
 	}
+	if *filename != "" {
+		fmt.Fprintln(os.Stderr, "-filename can only be used with stdin")
+		return 1
+	}
 	if *toJSON {
-		fmt.Fprintln(os.Stderr, "-tojson can only be used with stdin/out")
+		fmt.Fprintln(os.Stderr, "-tojson can only be used with stdin")
 		return 1
 	}
 	status := 0
@@ -196,15 +206,15 @@ Utilities:
 
 var errChangedWithDiff = fmt.Errorf("")
 
-func formatStdin() error {
+func formatStdin(name string) error {
 	if *write {
 		return fmt.Errorf("-w cannot be used on standard input")
 	}
 	src, err := ioutil.ReadAll(in)
 	if err != nil {
 		return err
 	}
-	return formatBytes(src, "<standard input>")
+	return formatBytes(src, name)
 }
 
 var vcsDir = regexp.MustCompile(`^\.(git|svn|hg)$`)

cmd/shfmt/testdata/scripts/editorconfig.txt

@@ -6,6 +6,14 @@ shfmt
 cmp stdout input.sh.golden
 ! stderr .
 
+# Verify that -filename works well with EditorConfig.
+stdin stdin-filename-bash
+shfmt
+
+stdin stdin-filename-bash
+! shfmt -filename=foo-posix.sh
+stderr '^foo-posix.sh:.* arrays are a bash'
+
 # Using a file path should use EditorConfig, including with the use of flags
 # like -l.
 shfmt input.sh
@@ -51,6 +59,9 @@ root = true
 [*]
 indent_style = space
 indent_size = 3
+
+[*-posix.sh]
+shell_variant = posix
 -- input.sh --
 {
 	indented
@@ -59,6 +70,10 @@ indent_size = 3
 {
    indented
 }
+-- stdin-filename-bash --
+array=(
+	element
+)
 -- morespaces/.editorconfig --
 [*.sh]
 indent_size = 6

cmd/shfmt/testdata/scripts/flags.txt

@@ -16,7 +16,10 @@ stderr 'cannot coexist'
 stderr 'unknown shell language'
 
 ! shfmt -tojson file
-stderr 'can only be used with stdin'
+stderr '-tojson can only be used with stdin'
+
+! shfmt -filename=foo file
+stderr '-filename can only be used with stdin'
 
 # Check all the -ln variations.
 stdin notbash.sh