Add --with-shell for shelling out with different command and flags (#…

…3746)

Close #3732

CHANGELOG.md

@@ -3,10 +3,23 @@ CHANGELOG
 
 0.51.0
 ------
+- Added `--with-shell` option to start child processes with a custom shell command and flags
+  ```sh
+  gem list | fzf --with-shell 'ruby -e' \
+    --preview 'pp Gem::Specification.find_by_name({1})' \
+    --bind 'ctrl-o:execute-silent:
+        spec = Gem::Specification.find_by_name({1})
+        [spec.homepage, *spec.metadata.filter { _1.end_with?("uri") }.values].uniq.each do
+          system "open", _1
+        end
+    '
+  ```
 - Added `change-multi` action for dynamically changing `--multi` option
     - `change-multi` - enable multi-select mode with no limit
     - `change-multi(NUM)` - enable multi-select mode with a limit
     - `change-multi(0)` - disable multi-select mode
+- `become` action is now supported on Windows
+    - Unlike in *nix, this does not use `execve(2)`. Instead it spawns a new process and waits for it to finish, so the exact behavior may differ.
 - Bug fixes and improvements
 
 0.50.0

man/man1/fzf.1

@@ -818,6 +818,16 @@ the finder only after the input stream is complete.
 e.g. \fBfzf --multi | fzf --sync\fR
 .RE
 .TP
+.B "--with-shell=STR"
+Shell command and flags to start child processes with. On *nix Systems, the
+default value is \fB$SHELL -c\fR if \fB$SHELL\fR is set, otherwise \fBsh -c\fR.
+On Windows, the default value is \fBcmd /v:on/s/c\fR when \fB$SHELL\fR is not
+set.
+
+.RS
+e.g. \fBgem list | fzf --with-shell 'ruby -e' --preview 'pp Gem::Specification.find_by_name({1})'\fR
+.RE
+.TP
 .B "--listen[=[ADDR:]PORT]" "--listen-unsafe[=[ADDR:]PORT]"
 Start HTTP server and listen on the given address. It allows external processes
 to send actions to perform via POST method.
@@ -932,6 +942,8 @@ you need to protect against DNS rebinding and privilege escalation attacks.
 .br
 .BR 2 "      Error"
 .br
+.BR 127 "    Invalid shell command for \fBbecome\fR action"
+.br
 .BR 130 "    Interrupted with \fBCTRL-C\fR or \fBESC\fR"
 
 .SH FIELD INDEX EXPRESSION
@@ -1441,8 +1453,6 @@ call.
 
     \fBfzf --bind "enter:become(vim {})"\fR
 
-\fBbecome(...)\fR is not supported on Windows.
-
 .SS RELOAD INPUT
 
 \fBreload(...)\fR action is used to dynamically update the input list

src/core.go

@@ -121,13 +121,16 @@ func Run(opts *Options, version string, revision string) {
 		})
 	}
 
+	// Process executor
+	executor := util.NewExecutor(opts.WithShell)
+
 	// Reader
 	streamingFilter := opts.Filter != nil && !sort && !opts.Tac && !opts.Sync
 	var reader *Reader
 	if !streamingFilter {
 		reader = NewReader(func(data []byte) bool {
 			return chunkList.Push(data)
-		}, eventBox, opts.ReadZero, opts.Filter == nil)
+		}, eventBox, executor, opts.ReadZero, opts.Filter == nil)
 		go reader.ReadSource(opts.WalkerRoot, opts.WalkerOpts, opts.WalkerSkip)
 	}
 
@@ -178,7 +181,7 @@ func Run(opts *Options, version string, revision string) {
 						mutex.Unlock()
 					}
 					return false
-				}, eventBox, opts.ReadZero, false)
+				}, eventBox, executor, opts.ReadZero, false)
 			reader.ReadSource(opts.WalkerRoot, opts.WalkerOpts, opts.WalkerSkip)
 		} else {
 			eventBox.Unwatch(EvtReadNew)
@@ -209,7 +212,7 @@ func Run(opts *Options, version string, revision string) {
 	go matcher.Loop()
 
 	// Terminal I/O
-	terminal := NewTerminal(opts, eventBox)
+	terminal := NewTerminal(opts, eventBox, executor)
 	maxFit := 0 // Maximum number of items that can fit on screen
 	padHeight := 0
 	heightUnknown := opts.Height.auto

src/options.go

@@ -120,6 +120,7 @@ const usage = `usage: fzf [options]
     --read0                Read input delimited by ASCII NUL characters
     --print0               Print output delimited by ASCII NUL characters
     --sync                 Synchronous search for multi-staged filtering
+    --with-shell=STR       Shell command and flags to start child processes with
     --listen[=[ADDR:]PORT] Start HTTP server to receive actions (POST /)
                            (To allow remote process execution, use --listen-unsafe)
     --version              Display version information and exit
@@ -356,6 +357,7 @@ type Options struct {
 	Unicode      bool
 	Ambidouble   bool
 	Tabstop      int
+	WithShell    string
 	ListenAddr   *listenAddress
 	Unsafe       bool
 	ClearOnExit  bool
@@ -1327,10 +1329,6 @@ func parseActionList(masked string, original string, prevActions []*action, putA
 					actions = append(actions, &action{t: t, a: actionArg})
 				}
 				switch t {
-				case actBecome:
-					if util.IsWindows() {
-						exit("become action is not supported on Windows")
-					}
 				case actUnbind, actRebind:
 					parseKeyChordsImpl(actionArg, spec[0:offset]+" target required", exit)
 				case actChangePreviewWindow:
@@ -1957,6 +1955,8 @@ func parseOptions(opts *Options, allArgs []string) {
 				nextString(allArgs, &i, "padding required (TRBL / TB,RL / T,RL,B / T,R,B,L)"))
 		case "--tabstop":
 			opts.Tabstop = nextInt(allArgs, &i, "tab stop required")
+		case "--with-shell":
+			opts.WithShell = nextString(allArgs, &i, "shell command and flags required")
 		case "--listen", "--listen-unsafe":
 			given, str := optionalNextString(allArgs, &i)
 			addr := defaultListenAddr
@@ -2073,6 +2073,8 @@ func parseOptions(opts *Options, allArgs []string) {
 				opts.Padding = parseMargin("padding", value)
 			} else if match, value := optString(arg, "--tabstop="); match {
 				opts.Tabstop = atoi(value)
+			} else if match, value := optString(arg, "--with-shell="); match {
+				opts.WithShell = value
 			} else if match, value := optString(arg, "--listen="); match {
 				addr, err := parseListenAddress(value)
 				if err != nil {

src/reader.go

@@ -18,6 +18,7 @@ import (
 // Reader reads from command or standard input
 type Reader struct {
 	pusher   func([]byte) bool
+	executor *util.Executor
 	eventBox *util.EventBox
 	delimNil bool
 	event    int32
@@ -30,8 +31,8 @@ type Reader struct {
 }
 
 // NewReader returns new Reader object
-func NewReader(pusher func([]byte) bool, eventBox *util.EventBox, delimNil bool, wait bool) *Reader {
-	return &Reader{pusher, eventBox, delimNil, int32(EvtReady), make(chan bool, 1), sync.Mutex{}, nil, nil, false, wait}
+func NewReader(pusher func([]byte) bool, eventBox *util.EventBox, executor *util.Executor, delimNil bool, wait bool) *Reader {
+	return &Reader{pusher, executor, eventBox, delimNil, int32(EvtReady), make(chan bool, 1), sync.Mutex{}, nil, nil, false, wait}
 }
 
 func (r *Reader) startEventPoller() {
@@ -242,7 +243,7 @@ func (r *Reader) readFromCommand(command string, environ []string) bool {
 	r.mutex.Lock()
 	r.killed = false
 	r.command = &command
-	r.exec = util.ExecCommand(command, true)
+	r.exec = r.executor.ExecCommand(command, true)
 	if environ != nil {
 		r.exec.Env = environ
 	}

src/reader_test.go

@@ -10,9 +10,10 @@ import (
 func TestReadFromCommand(t *testing.T) {
 	strs := []string{}
 	eb := util.NewEventBox()
+	exec := util.NewExecutor("")
 	reader := NewReader(
 		func(s []byte) bool { strs = append(strs, string(s)); return true },
-		eb, false, true)
+		eb, exec, false, true)
 
 	reader.startEventPoller()
 

src/terminal.go

@@ -7,7 +7,6 @@ import (
 	"io"
 	"math"
 	"os"
-	"os/exec"
 	"os/signal"
 	"regexp"
 	"sort"
@@ -245,6 +244,7 @@ type Terminal struct {
 	listenUnsafe       bool
 	borderShape        tui.BorderShape
 	cleanExit          bool
+	executor           *util.Executor
 	paused             bool
 	border             tui.Window
 	window             tui.Window
@@ -640,7 +640,7 @@ func evaluateHeight(opts *Options, termHeight int) int {
 }
 
 // NewTerminal returns new Terminal object
-func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
+func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor) *Terminal {
 	input := trimQuery(opts.Query)
 	var delay time.Duration
 	if opts.Tac {
@@ -736,6 +736,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox) *Terminal {
 		previewLabel:       nil,
 		previewLabelOpts:   opts.PreviewLabel,
 		cleanExit:          opts.ClearOnExit,
+		executor:           executor,
 		paused:             opts.Phony,
 		cycle:              opts.Cycle,
 		headerVisible:      true,
@@ -2522,6 +2523,7 @@ type replacePlaceholderParams struct {
 	allItems   []*Item
 	lastAction actionType
 	prompt     string
+	executor   *util.Executor
 }
 
 func (t *Terminal) replacePlaceholder(template string, forcePlus bool, input string, list []*Item) string {
@@ -2535,6 +2537,7 @@ func (t *Terminal) replacePlaceholder(template string, forcePlus bool, input str
 		allItems:   list,
 		lastAction: t.lastAction,
 		prompt:     t.promptString,
+		executor:   t.executor,
 	})
 }
 
@@ -2595,7 +2598,7 @@ func replacePlaceholder(params replacePlaceholderParams) string {
 		case escaped:
 			return match
 		case match == "{q}" || match == "{fzf:query}":
-			return quoteEntry(params.query)
+			return params.executor.QuoteEntry(params.query)
 		case match == "{}":
 			replace = func(item *Item) string {
 				switch {
@@ -2608,13 +2611,13 @@ func replacePlaceholder(params replacePlaceholderParams) string {
 				case flags.file:
 					return item.AsString(params.stripAnsi)
 				default:
-					return quoteEntry(item.AsString(params.stripAnsi))
+					return params.executor.QuoteEntry(item.AsString(params.stripAnsi))
 				}
 			}
 		case match == "{fzf:action}":
 			return params.lastAction.Name()
 		case match == "{fzf:prompt}":
-			return quoteEntry(params.prompt)
+			return params.executor.QuoteEntry(params.prompt)
 		default:
 			// token type and also failover (below)
 			rangeExpressions := strings.Split(match[1:len(match)-1], ",")
@@ -2648,7 +2651,7 @@ func replacePlaceholder(params replacePlaceholderParams) string {
 					str = strings.TrimSpace(str)
 				}
 				if !flags.file {
-					str = quoteEntry(str)
+					str = params.executor.QuoteEntry(str)
 				}
 				return str
 			}
@@ -2688,7 +2691,7 @@ func (t *Terminal) executeCommand(template string, forcePlus bool, background bo
 		return line
 	}
 	command := t.replacePlaceholder(template, forcePlus, string(t.input), list)
-	cmd := util.ExecCommand(command, false)
+	cmd := t.executor.ExecCommand(command, false)
 	cmd.Env = t.environ()
 	t.executing.Set(true)
 	if !background {
@@ -2965,7 +2968,7 @@ func (t *Terminal) Loop() {
 				if items[0] != nil {
 					_, query := t.Input()
 					command := t.replacePlaceholder(commandTemplate, false, string(query), items)
-					cmd := util.ExecCommand(command, true)
+					cmd := t.executor.ExecCommand(command, true)
 					env := t.environ()
 					if pwindowSize.Lines > 0 {
 						lines := fmt.Sprintf("LINES=%d", pwindowSize.Lines)
@@ -3372,27 +3375,21 @@ func (t *Terminal) Loop() {
 				valid, list := t.buildPlusList(a.a, false)
 				if valid {
 					command := t.replacePlaceholder(a.a, false, string(t.input), list)
-					shell := os.Getenv("SHELL")
-					if len(shell) == 0 {
-						shell = "sh"
-					}
-					shellPath, err := exec.LookPath(shell)
-					if err == nil {
-						t.tui.Close()
-						if t.history != nil {
-							t.history.append(string(t.input))
-						}
-						/*
-							FIXME: It is not at all clear why this is required.
-							The following command will report 'not a tty', unless we open
-							/dev/tty *twice* after closing the standard input for 'reload'
-							in Reader.terminate().
-								: | fzf --bind 'start:reload:ls' --bind 'enter:become:tty'
-						*/
-						tui.TtyIn()
-						util.SetStdin(tui.TtyIn())
-						syscall.Exec(shellPath, []string{shell, "-c", command}, os.Environ())
+					t.tui.Close()
+					if t.history != nil {
+						t.history.append(string(t.input))
 					}
+
+					/*
+					 FIXME: It is not at all clear why this is required.
+					 The following command will report 'not a tty', unless we open
+					 /dev/tty *twice* after closing the standard input for 'reload'
+					 in Reader.terminate().
+
+					   while : | fzf --bind 'start:reload:ls' --bind 'load:become:tty'; do echo; done
+					*/
+					tui.TtyIn()
+					t.executor.Become(tui.TtyIn(), t.environ(), command)
 				}
 			case actExecute, actExecuteSilent:
 				t.executeCommand(a.a, false, a.t == actExecuteSilent, false, false)

src/terminal_test.go

@@ -23,6 +23,7 @@ func replacePlaceholderTest(template string, stripAnsi bool, delimiter Delimiter
 		allItems:   allItems,
 		lastAction: actBackwardDeleteCharEof,
 		prompt:     "prompt",
+		executor:   util.NewExecutor(""),
 	})
 }
 
@@ -244,6 +245,7 @@ func TestQuoteEntry(t *testing.T) {
 	unixStyle := quotes{``, `'`, `'\''`, `"`, `\`}
 	windowsStyle := quotes{`^`, `^"`, `'`, `\^"`, `\\`}
 	var effectiveStyle quotes
+	exec := util.NewExecutor("")
 
 	if util.IsWindows() {
 		effectiveStyle = windowsStyle
@@ -278,7 +280,7 @@ func TestQuoteEntry(t *testing.T) {
 	}
 
 	for input, expected := range tests {
-		escaped := quoteEntry(input)
+		escaped := exec.QuoteEntry(input)
 		expected = templateToString(expected, effectiveStyle)
 		if escaped != expected {
 			t.Errorf("Input: %s, expected: %s, actual %s", input, expected, escaped)

src/terminal_unix.go

@@ -5,26 +5,11 @@ package fzf
 import (
 	"os"
 	"os/signal"
-	"strings"
 	"syscall"
 
 	"golang.org/x/sys/unix"
 )
 
-var escaper *strings.Replacer
-
-func init() {
-	tokens := strings.Split(os.Getenv("SHELL"), "/")
-	if tokens[len(tokens)-1] == "fish" {
-		// https://fishshell.com/docs/current/language.html#quotes
-		// > The only meaningful escape sequences in single quotes are \', which
-		// > escapes a single quote and \\, which escapes the backslash symbol.
-		escaper = strings.NewReplacer("\\", "\\\\", "'", "\\'")
-	} else {
-		escaper = strings.NewReplacer("'", "'\\''")
-	}
-}
-
 func notifyOnResize(resizeChan chan<- os.Signal) {
 	signal.Notify(resizeChan, syscall.SIGWINCH)
 }
@@ -41,7 +26,3 @@ func notifyStop(p *os.Process) {
 func notifyOnCont(resizeChan chan<- os.Signal) {
 	signal.Notify(resizeChan, syscall.SIGCONT)
 }
-
-func quoteEntry(entry string) string {
-	return "'" + escaper.Replace(entry) + "'"
-}