Refactor the code so that fzf can be used as a library

main.go

@@ -3,10 +3,12 @@ package main
 import (
 	_ "embed"
 	"fmt"
+	"os"
 	"strings"
 
 	fzf "github.com/junegunn/fzf/src"
 	"github.com/junegunn/fzf/src/protector"
+	"github.com/junegunn/fzf/src/util"
 )
 
 var version string = "0.51"
@@ -33,9 +35,19 @@ func printScript(label string, content []byte) {
 	fmt.Println("### end: " + label + " ###")
 }
 
+func errorExit(msg string) {
+	os.Stderr.WriteString(msg + "\n")
+	os.Exit(fzf.ExitError)
+}
+
 func main() {
 	protector.Protect()
-	options := fzf.ParseOptions()
+
+	options, err := fzf.ParseOptions(true, os.Args[1:])
+	if err != nil {
+		errorExit(err.Error())
+		return
+	}
 	if options.Bash {
 		printScript("key-bindings.bash", bashKeyBindings)
 		printScript("completion.bash", bashCompletion)
@@ -51,5 +63,9 @@ func main() {
 		fmt.Println("fzf_key_bindings")
 		return
 	}
-	fzf.Run(options, version, revision)
+	code, err := fzf.Run(options, version, revision)
+	if err != nil {
+		os.Stderr.WriteString(err.Error() + "\n")
+	}
+	util.Exit(code)
 }

main_test.go

@@ -143,6 +143,7 @@ func TestOSExitNotAllowed(t *testing.T) {
 		t.Skip("skipping: short test")
 	}
 	allowed := map[string]int{
+		"main.go":            1, // os.Exit allowed 1 time in "main.go"
 		"src/util/atexit.go": 1, // os.Exit allowed 1 time in "atexit.go"
 	}
 	var errOsExit bool

src/actiontype_string.go

@@ -37,92 +37,93 @@ func _() {
 	_ = x[actDeleteChar-26]
 	_ = x[actDeleteCharEof-27]
 	_ = x[actEndOfLine-28]
-	_ = x[actForwardChar-29]
+	_ = x[actFatal-29]
-	_ = x[actForwardWord-30]
+	_ = x[actForwardChar-30]
-	_ = x[actKillLine-31]
+	_ = x[actForwardWord-31]
-	_ = x[actKillWord-32]
+	_ = x[actKillLine-32]
-	_ = x[actUnixLineDiscard-33]
+	_ = x[actKillWord-33]
-	_ = x[actUnixWordRubout-34]
+	_ = x[actUnixLineDiscard-34]
-	_ = x[actYank-35]
+	_ = x[actUnixWordRubout-35]
-	_ = x[actBackwardKillWord-36]
+	_ = x[actYank-36]
-	_ = x[actSelectAll-37]
+	_ = x[actBackwardKillWord-37]
-	_ = x[actDeselectAll-38]
+	_ = x[actSelectAll-38]
-	_ = x[actToggle-39]
+	_ = x[actDeselectAll-39]
-	_ = x[actToggleSearch-40]
+	_ = x[actToggle-40]
-	_ = x[actToggleAll-41]
+	_ = x[actToggleSearch-41]
-	_ = x[actToggleDown-42]
+	_ = x[actToggleAll-42]
-	_ = x[actToggleUp-43]
+	_ = x[actToggleDown-43]
-	_ = x[actToggleIn-44]
+	_ = x[actToggleUp-44]
-	_ = x[actToggleOut-45]
+	_ = x[actToggleIn-45]
-	_ = x[actToggleTrack-46]
+	_ = x[actToggleOut-46]
-	_ = x[actToggleTrackCurrent-47]
+	_ = x[actToggleTrack-47]
-	_ = x[actToggleHeader-48]
+	_ = x[actToggleTrackCurrent-48]
-	_ = x[actTrackCurrent-49]
+	_ = x[actToggleHeader-49]
-	_ = x[actUntrackCurrent-50]
+	_ = x[actTrackCurrent-50]
-	_ = x[actDown-51]
+	_ = x[actUntrackCurrent-51]
-	_ = x[actUp-52]
+	_ = x[actDown-52]
-	_ = x[actPageUp-53]
+	_ = x[actUp-53]
-	_ = x[actPageDown-54]
+	_ = x[actPageUp-54]
-	_ = x[actPosition-55]
+	_ = x[actPageDown-55]
-	_ = x[actHalfPageUp-56]
+	_ = x[actPosition-56]
-	_ = x[actHalfPageDown-57]
+	_ = x[actHalfPageUp-57]
-	_ = x[actOffsetUp-58]
+	_ = x[actHalfPageDown-58]
-	_ = x[actOffsetDown-59]
+	_ = x[actOffsetUp-59]
-	_ = x[actJump-60]
+	_ = x[actOffsetDown-60]
-	_ = x[actJumpAccept-61]
+	_ = x[actJump-61]
-	_ = x[actPrintQuery-62]
+	_ = x[actJumpAccept-62]
-	_ = x[actRefreshPreview-63]
+	_ = x[actPrintQuery-63]
-	_ = x[actReplaceQuery-64]
+	_ = x[actRefreshPreview-64]
-	_ = x[actToggleSort-65]
+	_ = x[actReplaceQuery-65]
-	_ = x[actShowPreview-66]
+	_ = x[actToggleSort-66]
-	_ = x[actHidePreview-67]
+	_ = x[actShowPreview-67]
-	_ = x[actTogglePreview-68]
+	_ = x[actHidePreview-68]
-	_ = x[actTogglePreviewWrap-69]
+	_ = x[actTogglePreview-69]
-	_ = x[actTransform-70]
+	_ = x[actTogglePreviewWrap-70]
-	_ = x[actTransformBorderLabel-71]
+	_ = x[actTransform-71]
-	_ = x[actTransformHeader-72]
+	_ = x[actTransformBorderLabel-72]
-	_ = x[actTransformPreviewLabel-73]
+	_ = x[actTransformHeader-73]
-	_ = x[actTransformPrompt-74]
+	_ = x[actTransformPreviewLabel-74]
-	_ = x[actTransformQuery-75]
+	_ = x[actTransformPrompt-75]
-	_ = x[actPreview-76]
+	_ = x[actTransformQuery-76]
-	_ = x[actChangePreview-77]
+	_ = x[actPreview-77]
-	_ = x[actChangePreviewWindow-78]
+	_ = x[actChangePreview-78]
-	_ = x[actPreviewTop-79]
+	_ = x[actChangePreviewWindow-79]
-	_ = x[actPreviewBottom-80]
+	_ = x[actPreviewTop-80]
-	_ = x[actPreviewUp-81]
+	_ = x[actPreviewBottom-81]
-	_ = x[actPreviewDown-82]
+	_ = x[actPreviewUp-82]
-	_ = x[actPreviewPageUp-83]
+	_ = x[actPreviewDown-83]
-	_ = x[actPreviewPageDown-84]
+	_ = x[actPreviewPageUp-84]
-	_ = x[actPreviewHalfPageUp-85]
+	_ = x[actPreviewPageDown-85]
-	_ = x[actPreviewHalfPageDown-86]
+	_ = x[actPreviewHalfPageUp-86]
-	_ = x[actPrevHistory-87]
+	_ = x[actPreviewHalfPageDown-87]
-	_ = x[actPrevSelected-88]
+	_ = x[actPrevHistory-88]
-	_ = x[actPut-89]
+	_ = x[actPrevSelected-89]
-	_ = x[actNextHistory-90]
+	_ = x[actPut-90]
-	_ = x[actNextSelected-91]
+	_ = x[actNextHistory-91]
-	_ = x[actExecute-92]
+	_ = x[actNextSelected-92]
-	_ = x[actExecuteSilent-93]
+	_ = x[actExecute-93]
-	_ = x[actExecuteMulti-94]
+	_ = x[actExecuteSilent-94]
-	_ = x[actSigStop-95]
+	_ = x[actExecuteMulti-95]
-	_ = x[actFirst-96]
+	_ = x[actSigStop-96]
-	_ = x[actLast-97]
+	_ = x[actFirst-97]
-	_ = x[actReload-98]
+	_ = x[actLast-98]
-	_ = x[actReloadSync-99]
+	_ = x[actReload-99]
-	_ = x[actDisableSearch-100]
+	_ = x[actReloadSync-100]
-	_ = x[actEnableSearch-101]
+	_ = x[actDisableSearch-101]
-	_ = x[actSelect-102]
+	_ = x[actEnableSearch-102]
-	_ = x[actDeselect-103]
+	_ = x[actSelect-103]
-	_ = x[actUnbind-104]
+	_ = x[actDeselect-104]
-	_ = x[actRebind-105]
+	_ = x[actUnbind-105]
-	_ = x[actBecome-106]
+	_ = x[actRebind-106]
-	_ = x[actResponse-107]
+	_ = x[actBecome-107]
-	_ = x[actShowHeader-108]
+	_ = x[actResponse-108]
-	_ = x[actHideHeader-109]
+	_ = x[actShowHeader-109]
+	_ = x[actHideHeader-110]
 }
 
-const _actionType_name = "actIgnoreactStartactClickactInvalidactCharactMouseactBeginningOfLineactAbortactAcceptactAcceptNonEmptyactAcceptOrPrintQueryactBackwardCharactBackwardDeleteCharactBackwardDeleteCharEofactBackwardWordactCancelactChangeBorderLabelactChangeHeaderactChangeMultiactChangePreviewLabelactChangePromptactChangeQueryactClearScreenactClearQueryactClearSelectionactCloseactDeleteCharactDeleteCharEofactEndOfLineactForwardCharactForwardWordactKillLineactKillWordactUnixLineDiscardactUnixWordRuboutactYankactBackwardKillWordactSelectAllactDeselectAllactToggleactToggleSearchactToggleAllactToggleDownactToggleUpactToggleInactToggleOutactToggleTrackactToggleTrackCurrentactToggleHeaderactTrackCurrentactUntrackCurrentactDownactUpactPageUpactPageDownactPositionactHalfPageUpactHalfPageDownactOffsetUpactOffsetDownactJumpactJumpAcceptactPrintQueryactRefreshPreviewactReplaceQueryactToggleSortactShowPreviewactHidePreviewactTogglePreviewactTogglePreviewWrapactTransformactTransformBorderLabelactTransformHeaderactTransformPreviewLabelactTransformPromptactTransformQueryactPreviewactChangePreviewactChangePreviewWindowactPreviewTopactPreviewBottomactPreviewUpactPreviewDownactPreviewPageUpactPreviewPageDownactPreviewHalfPageUpactPreviewHalfPageDownactPrevHistoryactPrevSelectedactPutactNextHistoryactNextSelectedactExecuteactExecuteSilentactExecuteMultiactSigStopactFirstactLastactReloadactReloadSyncactDisableSearchactEnableSearchactSelectactDeselectactUnbindactRebindactBecomeactResponseactShowHeaderactHideHeader"
+const _actionType_name = "actIgnoreactStartactClickactInvalidactCharactMouseactBeginningOfLineactAbortactAcceptactAcceptNonEmptyactAcceptOrPrintQueryactBackwardCharactBackwardDeleteCharactBackwardDeleteCharEofactBackwardWordactCancelactChangeBorderLabelactChangeHeaderactChangeMultiactChangePreviewLabelactChangePromptactChangeQueryactClearScreenactClearQueryactClearSelectionactCloseactDeleteCharactDeleteCharEofactEndOfLineactFatalactForwardCharactForwardWordactKillLineactKillWordactUnixLineDiscardactUnixWordRuboutactYankactBackwardKillWordactSelectAllactDeselectAllactToggleactToggleSearchactToggleAllactToggleDownactToggleUpactToggleInactToggleOutactToggleTrackactToggleTrackCurrentactToggleHeaderactTrackCurrentactUntrackCurrentactDownactUpactPageUpactPageDownactPositionactHalfPageUpactHalfPageDownactOffsetUpactOffsetDownactJumpactJumpAcceptactPrintQueryactRefreshPreviewactReplaceQueryactToggleSortactShowPreviewactHidePreviewactTogglePreviewactTogglePreviewWrapactTransformactTransformBorderLabelactTransformHeaderactTransformPreviewLabelactTransformPromptactTransformQueryactPreviewactChangePreviewactChangePreviewWindowactPreviewTopactPreviewBottomactPreviewUpactPreviewDownactPreviewPageUpactPreviewPageDownactPreviewHalfPageUpactPreviewHalfPageDownactPrevHistoryactPrevSelectedactPutactNextHistoryactNextSelectedactExecuteactExecuteSilentactExecuteMultiactSigStopactFirstactLastactReloadactReloadSyncactDisableSearchactEnableSearchactSelectactDeselectactUnbindactRebindactBecomeactResponseactShowHeaderactHideHeader"
 
-var _actionType_index = [...]uint16{0, 9, 17, 25, 35, 42, 50, 68, 76, 85, 102, 123, 138, 159, 183, 198, 207, 227, 242, 256, 277, 292, 306, 320, 333, 350, 358, 371, 387, 399, 413, 427, 438, 449, 467, 484, 491, 510, 522, 536, 545, 560, 572, 585, 596, 607, 619, 633, 654, 669, 684, 701, 708, 713, 722, 733, 744, 757, 772, 783, 796, 803, 816, 829, 846, 861, 874, 888, 902, 918, 938, 950, 973, 991, 1015, 1033, 1050, 1060, 1076, 1098, 1111, 1127, 1139, 1153, 1169, 1187, 1207, 1229, 1243, 1258, 1264, 1278, 1293, 1303, 1319, 1334, 1344, 1352, 1359, 1368, 1381, 1397, 1412, 1421, 1432, 1441, 1450, 1459, 1470, 1483, 1496}
+var _actionType_index = [...]uint16{0, 9, 17, 25, 35, 42, 50, 68, 76, 85, 102, 123, 138, 159, 183, 198, 207, 227, 242, 256, 277, 292, 306, 320, 333, 350, 358, 371, 387, 399, 407, 421, 435, 446, 457, 475, 492, 499, 518, 530, 544, 553, 568, 580, 593, 604, 615, 627, 641, 662, 677, 692, 709, 716, 721, 730, 741, 752, 765, 780, 791, 804, 811, 824, 837, 854, 869, 882, 896, 910, 926, 946, 958, 981, 999, 1023, 1041, 1058, 1068, 1084, 1106, 1119, 1135, 1147, 1161, 1177, 1195, 1215, 1237, 1251, 1266, 1272, 1286, 1301, 1311, 1327, 1342, 1352, 1360, 1367, 1376, 1389, 1405, 1420, 1429, 1440, 1449, 1458, 1467, 1478, 1491, 1504}
 
 func (i actionType) String() string {
 	if i < 0 || i >= actionType(len(_actionType_index)-1) {

src/constants.go

@@ -67,9 +67,9 @@ const (
 )
 
 const (
-	exitCancel    = -1
+	ExitCancel    = -1
-	exitOk        = 0
+	ExitOk        = 0
-	exitNoMatch   = 1
+	ExitNoMatch   = 1
-	exitError     = 2
+	ExitError     = 2
-	exitInterrupt = 130
+	ExitInterrupt = 130
 )

src/core.go

@@ -28,7 +28,7 @@ func sbytes(data string) []byte {
 }
 
 // Run starts fzf
-func Run(opts *Options, version string, revision string) {
+func Run(opts *Options, version string, revision string) (int, error) {
 	defer util.RunAtExitFuncs()
 
 	sort := opts.Sort > 0
@@ -40,7 +40,7 @@ func Run(opts *Options, version string, revision string) {
 		} else {
 			fmt.Println(version)
 		}
-		util.Exit(exitOk)
+		return ExitOk, nil
 	}
 
 	// Event channel
@@ -197,9 +197,9 @@ func Run(opts *Options, version string, revision string) {
 			}
 		}
 		if found {
-			util.Exit(exitOk)
+			return ExitOk, nil
 		}
-		util.Exit(exitNoMatch)
+		return ExitNoMatch, nil
 	}
 
 	// Synchronous search
@@ -210,9 +210,13 @@ func Run(opts *Options, version string, revision string) {
 
 	// Go interactive
 	go matcher.Loop()
+	defer matcher.Stop()
 
 	// Terminal I/O
-	terminal := NewTerminal(opts, eventBox, executor)
+	terminal, err := NewTerminal(opts, eventBox, executor)
+	if err != nil {
+		return ExitError, err
+	}
 	maxFit := 0 // Maximum number of items that can fit on screen
 	padHeight := 0
 	heightUnknown := opts.Height.auto
@@ -258,7 +262,10 @@ func Run(opts *Options, version string, revision string) {
 		header = make([]string, 0, opts.HeaderLines)
 		go reader.restart(command, environ)
 	}
-	for {
+
+	exitCode := ExitOk
+	running := true
+	for running {
 		delay := true
 		ticks++
 		input := func() []rune {
@@ -278,7 +285,9 @@ func Run(opts *Options, version string, revision string) {
 					if reading {
 						reader.terminate()
 					}
-					util.Exit(value.(int))
+					exitCode = value.(int)
+					running = false
+					return
 				case EvtReadNew, EvtReadFin:
 					if evt == EvtReadFin && nextCommand != nil {
 						restart(*nextCommand, nextEnviron)
@@ -378,10 +387,11 @@ func Run(opts *Options, version string, revision string) {
 									for i := 0; i < count; i++ {
 										opts.Printer(val.Get(i).item.AsString(opts.Ansi))
 									}
-									if count > 0 {
+									if count == 0 {
-										util.Exit(exitOk)
+										exitCode = ExitNoMatch
 									}
-									util.Exit(exitNoMatch)
+									running = false
+									return
 								}
 								determine(val.final)
 							}
@@ -399,4 +409,5 @@ func Run(opts *Options, version string, revision string) {
 			time.Sleep(dur)
 		}
 	}
+	return exitCode, nil
 }

src/matcher.go

@@ -35,6 +35,7 @@ type Matcher struct {
 const (
 	reqRetry util.EventType = iota
 	reqReset
+	reqStop
 )
 
 // NewMatcher returns a new Matcher
@@ -60,8 +61,13 @@ func (m *Matcher) Loop() {
 	for {
 		var request MatchRequest
 
+		stop := false
 		m.reqBox.Wait(func(events *util.Events) {
-			for _, val := range *events {
+			for t, val := range *events {
+				if t == reqStop {
+					stop = true
+					return
+				}
 				switch val := val.(type) {
 				case MatchRequest:
 					request = val
@@ -71,6 +77,9 @@ func (m *Matcher) Loop() {
 			}
 			events.Clear()
 		})
+		if stop {
+			break
+		}
 
 		if request.sort != m.sort || request.revision != m.revision {
 			m.sort = request.sort
@@ -236,3 +245,7 @@ func (m *Matcher) Reset(chunks []*Chunk, patternRunes []rune, cancel bool, final
 	}
 	m.reqBox.Set(event, MatchRequest{chunks, pattern, final, sort && pattern.sortable, revision})
 }
+
+func (m *Matcher) Stop() {
+	m.reqBox.Set(reqStop, MatchRequest{})
+}

src/options_no_pprof.go

@@ -3,9 +3,11 @@
 
 package fzf
 
+import "errors"
+
 func (o *Options) initProfiling() error {
 	if o.CPUProfile != "" || o.MEMProfile != "" || o.BlockProfile != "" || o.MutexProfile != "" {
-		errorExit("error: profiling not supported: FZF must be built with '-tags=pprof' to enable profiling")
+		return errors.New("error: profiling not supported: FZF must be built with '-tags=pprof' to enable profiling")
 	}
 	return nil
 }

src/options_test.go

@@ -80,7 +80,7 @@ func TestDelimiterRegexRegexCaret(t *testing.T) {
 
 func TestSplitNth(t *testing.T) {
 	{
-		ranges := splitNth("..")
+		ranges, _ := splitNth("..")
 		if len(ranges) != 1 ||
 			ranges[0].begin != rangeEllipsis ||
 			ranges[0].end != rangeEllipsis {
@@ -88,7 +88,7 @@ func TestSplitNth(t *testing.T) {
 		}
 	}
 	{
-		ranges := splitNth("..3,1..,2..3,4..-1,-3..-2,..,2,-2,2..-2,1..-1")
+		ranges, _ := splitNth("..3,1..,2..3,4..-1,-3..-2,..,2,-2,2..-2,1..-1")
 		if len(ranges) != 10 ||
 			ranges[0].begin != rangeEllipsis || ranges[0].end != 3 ||
 			ranges[1].begin != rangeEllipsis || ranges[1].end != rangeEllipsis ||
@@ -137,7 +137,7 @@ func TestIrrelevantNth(t *testing.T) {
 }
 
 func TestParseKeys(t *testing.T) {
-	pairs := parseKeyChords("ctrl-z,alt-z,f2,@,Alt-a,!,ctrl-G,J,g,ctrl-alt-a,ALT-enter,alt-SPACE", "")
+	pairs, _ := parseKeyChords("ctrl-z,alt-z,f2,@,Alt-a,!,ctrl-G,J,g,ctrl-alt-a,ALT-enter,alt-SPACE", "")
 	checkEvent := func(e tui.Event, s string) {
 		if pairs[e] != s {
 			t.Errorf("%s != %s", pairs[e], s)
@@ -163,7 +163,7 @@ func TestParseKeys(t *testing.T) {
 	checkEvent(tui.AltKey(' '), "alt-SPACE")
 
 	// Synonyms
-	pairs = parseKeyChords("enter,Return,space,tab,btab,esc,up,down,left,right", "")
+	pairs, _ = parseKeyChords("enter,Return,space,tab,btab,esc,up,down,left,right", "")
 	if len(pairs) != 9 {
 		t.Error(9)
 	}
@@ -177,7 +177,7 @@ func TestParseKeys(t *testing.T) {
 	check(tui.Left, "left")
 	check(tui.Right, "right")
 
-	pairs = parseKeyChords("Tab,Ctrl-I,PgUp,page-up,pgdn,Page-Down,Home,End,Alt-BS,Alt-BSpace,shift-left,shift-right,btab,shift-tab,return,Enter,bspace", "")
+	pairs, _ = parseKeyChords("Tab,Ctrl-I,PgUp,page-up,pgdn,Page-Down,Home,End,Alt-BS,Alt-BSpace,shift-left,shift-right,btab,shift-tab,return,Enter,bspace", "")
 	if len(pairs) != 11 {
 		t.Error(11)
 	}
@@ -206,40 +206,40 @@ func TestParseKeysWithComma(t *testing.T) {
 		}
 	}
 
-	pairs := parseKeyChords(",", "")
+	pairs, _ := parseKeyChords(",", "")
 	checkN(len(pairs), 1)
 	check(pairs, tui.Key(','), ",")
 
-	pairs = parseKeyChords(",,a,b", "")
+	pairs, _ = parseKeyChords(",,a,b", "")
 	checkN(len(pairs), 3)
 	check(pairs, tui.Key('a'), "a")
 	check(pairs, tui.Key('b'), "b")
 	check(pairs, tui.Key(','), ",")
 
-	pairs = parseKeyChords("a,b,,", "")
+	pairs, _ = parseKeyChords("a,b,,", "")
 	checkN(len(pairs), 3)
 	check(pairs, tui.Key('a'), "a")
 	check(pairs, tui.Key('b'), "b")
 	check(pairs, tui.Key(','), ",")
 
-	pairs = parseKeyChords("a,,,b", "")
+	pairs, _ = parseKeyChords("a,,,b", "")
 	checkN(len(pairs), 3)
 	check(pairs, tui.Key('a'), "a")
 	check(pairs, tui.Key('b'), "b")
 	check(pairs, tui.Key(','), ",")
 
-	pairs = parseKeyChords("a,,,b,c", "")
+	pairs, _ = parseKeyChords("a,,,b,c", "")
 	checkN(len(pairs), 4)
 	check(pairs, tui.Key('a'), "a")
 	check(pairs, tui.Key('b'), "b")
 	check(pairs, tui.Key('c'), "c")
 	check(pairs, tui.Key(','), ",")
 
-	pairs = parseKeyChords(",,,", "")
+	pairs, _ = parseKeyChords(",,,", "")
 	checkN(len(pairs), 1)
 	check(pairs, tui.Key(','), ",")
 
-	pairs = parseKeyChords(",ALT-,,", "")
+	pairs, _ = parseKeyChords(",ALT-,,", "")
 	checkN(len(pairs), 1)
 	check(pairs, tui.AltKey(','), "ALT-,")
 }
@@ -262,17 +262,13 @@ func TestBind(t *testing.T) {
 		}
 	}
 	check(tui.CtrlA.AsEvent(), "", actBeginningOfLine)
-	errorString := ""
-	errorFn := func(e string) {
-		errorString = e
-	}
 	parseKeymap(keymap,
 		"ctrl-a:kill-line,ctrl-b:toggle-sort+up+down,c:page-up,alt-z:page-down,"+
 			"f1:execute(ls {+})+abort+execute(echo \n{+})+select-all,f2:execute/echo {}, {}, {}/,f3:execute[echo '({})'],f4:execute;less {};,"+
 			"alt-a:execute-Multi@echo (,),[,],/,:,;,%,{}@,alt-b:execute;echo (,),[,],/,:,@,%,{};,"+
 			"x:Execute(foo+bar),X:execute/bar+baz/"+
 			",f1:+first,f1:+top"+
-			",,:abort,::accept,+:execute:++\nfoobar,Y:execute(baz)+up", errorFn)
+			",,:abort,::accept,+:execute:++\nfoobar,Y:execute(baz)+up")
 	check(tui.CtrlA.AsEvent(), "", actKillLine)
 	check(tui.CtrlB.AsEvent(), "", actToggleSort, actUp, actDown)
 	check(tui.Key('c'), "", actPageUp)
@@ -290,20 +286,17 @@ func TestBind(t *testing.T) {
 	check(tui.Key('+'), "++\nfoobar,Y:execute(baz)+up", actExecute)
 
 	for idx, char := range []rune{'~', '!', '@', '#', '$', '%', '^', '&', '*', '|', ';', '/'} {
-		parseKeymap(keymap, fmt.Sprintf("%d:execute%cfoobar%c", idx%10, char, char), errorFn)
+		parseKeymap(keymap, fmt.Sprintf("%d:execute%cfoobar%c", idx%10, char, char))
 		check(tui.Key([]rune(fmt.Sprintf("%d", idx%10))[0]), "foobar", actExecute)
 	}
 
-	parseKeymap(keymap, "f1:abort", errorFn)
+	parseKeymap(keymap, "f1:abort")
 	check(tui.F1.AsEvent(), "", actAbort)
-	if len(errorString) > 0 {
-		t.Errorf("error parsing keymap: %s", errorString)
-	}
 }
 
 func TestColorSpec(t *testing.T) {
 	theme := tui.Dark256
-	dark := parseTheme(theme, "dark")
+	dark, _ := parseTheme(theme, "dark")
 	if *dark != *theme {
 		t.Errorf("colors should be equivalent")
 	}
@@ -311,7 +304,7 @@ func TestColorSpec(t *testing.T) {
 		t.Errorf("point should not be equivalent")
 	}
 
-	light := parseTheme(theme, "dark,light")
+	light, _ := parseTheme(theme, "dark,light")
 	if *light == *theme {
 		t.Errorf("should not be equivalent")
 	}
@@ -322,7 +315,7 @@ func TestColorSpec(t *testing.T) {
 		t.Errorf("point should not be equivalent")
 	}
 
-	customized := parseTheme(theme, "fg:231,bg:232")
+	customized, _ := parseTheme(theme, "fg:231,bg:232")
 	if customized.Fg.Color != 231 || customized.Bg.Color != 232 {
 		t.Errorf("color not customized")
 	}
@@ -335,7 +328,7 @@ func TestColorSpec(t *testing.T) {
 		t.Errorf("colors should now be equivalent: %v, %v", tui.Dark256, customized)
 	}
 
-	customized = parseTheme(theme, "fg:231,dark,bg:232")
+	customized, _ = parseTheme(theme, "fg:231,dark,bg:232")
 	if customized.Fg != tui.Dark256.Fg || customized.Bg == tui.Dark256.Bg {
 		t.Errorf("color not customized")
 	}
@@ -475,7 +468,7 @@ func TestValidateSign(t *testing.T) {
 }
 
 func TestParseSingleActionList(t *testing.T) {
-	actions := parseSingleActionList("Execute@foo+bar,baz@+up+up+reload:down+down", func(string) {})
+	actions, _ := parseSingleActionList("Execute@foo+bar,baz@+up+up+reload:down+down")
 	if len(actions) != 4 {
 		t.Errorf("Invalid number of actions parsed:%d", len(actions))
 	}
@@ -491,11 +484,8 @@ func TestParseSingleActionList(t *testing.T) {
 }
 
 func TestParseSingleActionListError(t *testing.T) {
-	err := ""
+	_, err := parseSingleActionList("change-query(foobar)baz")
-	parseSingleActionList("change-query(foobar)baz", func(e string) {
+	if err == nil {
-		err = e
-	})
-	if len(err) == 0 {
 		t.Errorf("Failed to detect error")
 	}
 }

src/server.go

@@ -73,28 +73,28 @@ func parseListenAddress(address string) (listenAddress, error) {
 	return listenAddress{parts[0], port}, nil
 }
 
-func startHttpServer(address listenAddress, actionChannel chan []*action, responseChannel chan string) (int, error) {
+func startHttpServer(address listenAddress, actionChannel chan []*action, responseChannel chan string) (net.Listener, int, error) {
 	host := address.host
 	port := address.port
 	apiKey := os.Getenv("FZF_API_KEY")
 	if !address.IsLocal() && len(apiKey) == 0 {
-		return port, errors.New("FZF_API_KEY is required to allow remote access")
+		return nil, port, errors.New("FZF_API_KEY is required to allow remote access")
 	}
 	addrStr := fmt.Sprintf("%s:%d", host, port)
 	listener, err := net.Listen("tcp", addrStr)
 	if err != nil {
-		return port, fmt.Errorf("failed to listen on %s", addrStr)
+		return nil, port, fmt.Errorf("failed to listen on %s", addrStr)
 	}
 	if port == 0 {
 		addr := listener.Addr().String()
 		parts := strings.Split(addr, ":")
 		if len(parts) < 2 {
-			return port, fmt.Errorf("cannot extract port: %s", addr)
+			return nil, port, fmt.Errorf("cannot extract port: %s", addr)
 		}
 		var err error
 		port, err = strconv.Atoi(parts[len(parts)-1])
 		if err != nil {
-			return port, err
+			return nil, port, err
 		}
 	}
 
@@ -109,7 +109,7 @@ func startHttpServer(address listenAddress, actionChannel chan []*action, respon
 			conn, err := listener.Accept()
 			if err != nil {
 				if errors.Is(err, net.ErrClosed) {
-					break
+					return
 				} else {
 					continue
 				}
@@ -117,10 +117,9 @@ func startHttpServer(address listenAddress, actionChannel chan []*action, respon
 			conn.Write([]byte(server.handleHttpRequest(conn)))
 			conn.Close()
 		}
-		listener.Close()
 	}()
 
-	return port, nil
+	return listener, port, nil
 }
 
 // Here we are writing a simplistic HTTP server without using net/http
@@ -217,12 +216,9 @@ func (server *httpServer) handleHttpRequest(conn net.Conn) string {
 	}
 	body = body[:contentLength]
 
-	errorMessage := ""
+	actions, err := parseSingleActionList(strings.Trim(string(body), "\r\n"))
-	actions := parseSingleActionList(strings.Trim(string(body), "\r\n"), func(message string) {
+	if err != nil {
-		errorMessage = message
+		return bad(err.Error())
-	})
-	if len(errorMessage) > 0 {
-		return bad(errorMessage)
 	}
 	if len(actions) == 0 {
 		return bad("no action specified")

src/terminal.go

@@ -2,10 +2,12 @@ package fzf
 
 import (
 	"bufio"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
 	"math"
+	"net"
 	"os"
 	"os/signal"
 	"regexp"
@@ -49,6 +51,7 @@ var whiteSuffix *regexp.Regexp
 var offsetComponentRegex *regexp.Regexp
 var offsetTrimCharsRegex *regexp.Regexp
 var activeTempFiles []string
+var activeTempFilesMutex sync.Mutex
 var passThroughRegex *regexp.Regexp
 var actionTypeRegex *regexp.Regexp
 
@@ -63,6 +66,7 @@ func init() {
 	offsetComponentRegex = regexp.MustCompile(`([+-][0-9]+)|(-?/[1-9][0-9]*)`)
 	offsetTrimCharsRegex = regexp.MustCompile(`[^0-9/+-]`)
 	activeTempFiles = []string{}
+	activeTempFilesMutex = sync.Mutex{}
 
 	// Parts of the preview output that should be passed through to the terminal
 	// * https://github.com/tmux/tmux/wiki/FAQ#what-is-the-passthrough-escape-sequence-and-how-do-i-use-it
@@ -241,6 +245,7 @@ type Terminal struct {
 	unicode            bool
 	listenAddr         *listenAddress
 	listenPort         *int
+	listener           net.Listener
 	listenUnsafe       bool
 	borderShape        tui.BorderShape
 	cleanExit          bool
@@ -259,7 +264,7 @@ type Terminal struct {
 	hasResizeActions   bool
 	triggerLoad        bool
 	reading            bool
-	running            bool
+	running            *util.AtomicBool
 	failed             *string
 	jumping            jumpMode
 	jumpLabels         string
@@ -278,12 +283,12 @@ type Terminal struct {
 	previewBox         *util.EventBox
 	eventBox           *util.EventBox
 	mutex              sync.Mutex
-	initFunc           func()
+	initFunc           func() error
 	prevLines          []itemLine
 	suppress           bool
 	sigstop            bool
 	startChan          chan fitpad
-	killChan           chan int
+	killChan           chan bool
 	serverInputChan    chan []*action
 	serverOutputChan   chan string
 	eventChan          chan tui.Event
@@ -340,6 +345,7 @@ const (
 	reqPreviewRefresh
 	reqPreviewDelayed
 	reqQuit
+	reqFatal
 )
 
 type action struct {
@@ -380,6 +386,7 @@ const (
 	actDeleteChar
 	actDeleteCharEof
 	actEndOfLine
+	actFatal
 	actForwardChar
 	actForwardWord
 	actKillLine
@@ -537,6 +544,7 @@ func defaultKeymap() map[tui.Event][]*action {
 		keymap[e] = toActions(a)
 	}
 
+	add(tui.Fatal, actFatal)
 	add(tui.Invalid, actInvalid)
 	add(tui.CtrlA, actBeginningOfLine)
 	add(tui.CtrlB, actBackwardChar)
@@ -642,7 +650,7 @@ func evaluateHeight(opts *Options, termHeight int) int {
 }
 
 // NewTerminal returns new Terminal object
-func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor) *Terminal {
+func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor) (*Terminal, error) {
 	input := trimQuery(opts.Query)
 	var delay time.Duration
 	if opts.Tac {
@@ -660,11 +668,12 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 	}
 	var renderer tui.Renderer
 	fullscreen := !opts.Height.auto && (opts.Height.size == 0 || opts.Height.percent && opts.Height.size == 100)
+	var err error
 	if fullscreen {
 		if tui.HasFullscreenRenderer() {
 			renderer = tui.NewFullscreenRenderer(opts.Theme, opts.Black, opts.Mouse)
 		} else {
-			renderer = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit,
+			renderer, err = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit,
 				true, func(h int) int { return h })
 		}
 	} else {
@@ -680,7 +689,10 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 			effectiveMinHeight += borderLines(opts.BorderShape)
 			return util.Min(termHeight, util.Max(evaluateHeight(opts, termHeight), effectiveMinHeight))
 		}
-		renderer = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit, false, maxHeightFunc)
+		renderer, err = tui.NewLightRenderer(opts.Theme, opts.Black, opts.Mouse, opts.Tabstop, opts.ClearOnExit, false, maxHeightFunc)
+	}
+	if err != nil {
+		return nil, err
 	}
 	wordRubout := "[^\\pL\\pN][\\pL\\pN]"
 	wordNext := "[\\pL\\pN][^\\pL\\pN]|(.$)"
@@ -693,6 +705,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 	for key, action := range opts.Keymap {
 		keymapCopy[key] = action
 	}
+
 	t := Terminal{
 		initDelay:          delay,
 		infoStyle:          opts.InfoStyle,
@@ -754,7 +767,7 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 		hasLoadActions:     false,
 		triggerLoad:        false,
 		reading:            true,
-		running:            true,
+		running:            util.NewAtomicBool(true),
 		failed:             nil,
 		jumping:            jumpDisabled,
 		jumpLabels:         opts.JumpLabels,
@@ -775,12 +788,12 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 		slab:               util.MakeSlab(slab16Size, slab32Size),
 		theme:              opts.Theme,
 		startChan:          make(chan fitpad, 1),
-		killChan:           make(chan int),
+		killChan:           make(chan bool),
 		serverInputChan:    make(chan []*action, 100),
 		serverOutputChan:   make(chan string),
 		eventChan:          make(chan tui.Event, 6), // (load + result + zero|one) | (focus) | (resize) | (GetChar)
 		tui:                renderer,
-		initFunc:           func() { renderer.Init() },
+		initFunc:           func() error { return renderer.Init() },
 		executing:          util.NewAtomicBool(false),
 		lastAction:         actStart,
 		lastFocus:          minItem.Index()}
@@ -832,14 +845,15 @@ func NewTerminal(opts *Options, eventBox *util.EventBox, executor *util.Executor
 	_, t.hasLoadActions = t.keymap[tui.Load.AsEvent()]
 
 	if t.listenAddr != nil {
-		port, err := startHttpServer(*t.listenAddr, t.serverInputChan, t.serverOutputChan)
+		listener, port, err := startHttpServer(*t.listenAddr, t.serverInputChan, t.serverOutputChan)
 		if err != nil {
-			errorExit(err.Error())
+			return nil, err
 		}
+		t.listener = listener
 		t.listenPort = &port
 	}
 
-	return &t
+	return &t, nil
 }
 
 func (t *Terminal) environ() []string {
@@ -2512,21 +2526,27 @@ func hasPreviewFlags(template string) (slot bool, plus bool, forceUpdate bool) {
 func writeTemporaryFile(data []string, printSep string) string {
 	f, err := os.CreateTemp("", "fzf-preview-*")
 	if err != nil {
-		errorExit("Unable to create temporary file")
+		// Unable to create temporary file
+		// FIXME: Should we terminate the program?
+		return ""
 	}
 	defer f.Close()
 
 	f.WriteString(strings.Join(data, printSep))
 	f.WriteString(printSep)
+	activeTempFilesMutex.Lock()
 	activeTempFiles = append(activeTempFiles, f.Name())
+	activeTempFilesMutex.Unlock()
 	return f.Name()
 }
 
 func cleanTemporaryFiles() {
+	activeTempFilesMutex.Lock()
 	for _, filename := range activeTempFiles {
 		os.Remove(filename)
 	}
 	activeTempFiles = []string{}
+	activeTempFilesMutex.Unlock()
 }
 
 type replacePlaceholderParams struct {
@@ -2836,18 +2856,18 @@ func (t *Terminal) toggleItem(item *Item) bool {
 	return true
 }
 
-func (t *Terminal) killPreview(code int) {
+func (t *Terminal) killPreview() {
 	select {
-	case t.killChan <- code:
+	case t.killChan <- true:
 	default:
-		if code != exitCancel {
-			t.eventBox.Set(EvtQuit, code)
-		}
 	}
 }
 
 func (t *Terminal) cancelPreview() {
-	t.killPreview(exitCancel)
+	select {
+	case t.killChan <- false:
+	default:
+	}
 }
 
 func (t *Terminal) pwindowSize() tui.TermSize {
@@ -2871,7 +2891,7 @@ func (t *Terminal) currentIndex() int32 {
 }
 
 // Loop is called to start Terminal I/O
-func (t *Terminal) Loop() {
+func (t *Terminal) Loop() error {
 	// prof := profile.Start(profile.ProfilePath("/tmp/"))
 	fitpad := <-t.startChan
 	fit := fitpad.fit
@@ -2895,14 +2915,23 @@ func (t *Terminal) Loop() {
 			return util.Min(termHeight, contentHeight+pad)
 		})
 	}
+
+	// Context
+	ctx, cancel := context.WithCancel(context.Background())
+
 	{ // Late initialization
 		intChan := make(chan os.Signal, 1)
 		signal.Notify(intChan, os.Interrupt, syscall.SIGTERM)
 		go func() {
-			for s := range intChan {
+			for {
-				// Don't quit by SIGINT while executing because it should be for the executing command and not for fzf itself
+				select {
-				if !(s == os.Interrupt && t.executing.Get()) {
+				case <-ctx.Done():
-					t.reqBox.Set(reqQuit, nil)
+					return
+				case s := <-intChan:
+					// Don't quit by SIGINT while executing because it should be for the executing command and not for fzf itself
+					if !(s == os.Interrupt && t.executing.Get()) {
+						t.reqBox.Set(reqQuit, nil)
+					}
 				}
 			}
 		}()
@@ -2911,8 +2940,12 @@ func (t *Terminal) Loop() {
 		notifyOnCont(contChan)
 		go func() {
 			for {
-				<-contChan
+				select {
-				t.reqBox.Set(reqReinit, nil)
+				case <-ctx.Done():
+					return
+				case <-contChan:
+					t.reqBox.Set(reqReinit, nil)
+				}
 			}
 		}()
 
@@ -2921,14 +2954,21 @@ func (t *Terminal) Loop() {
 			notifyOnResize(resizeChan) // Non-portable
 			go func() {
 				for {
-					<-resizeChan
+					select {
-					t.reqBox.Set(reqResize, nil)
+					case <-ctx.Done():
+						return
+					case <-resizeChan:
+						t.reqBox.Set(reqResize, nil)
+					}
 				}
 			}()
 		}
 
 		t.mutex.Lock()
-		t.initFunc()
+		if err := t.initFunc(); err != nil {
+			t.mutex.Unlock()
+			return err
+		}
 		t.termSize = t.tui.Size()
 		t.resizeWindows(false)
 		t.window.Erase()
@@ -2945,7 +2985,7 @@ func (t *Terminal) Loop() {
 
 		// Keep the spinner spinning
 		go func() {
-			for {
+			for t.running.Get() {
 				t.mutex.Lock()
 				reading := t.reading
 				t.mutex.Unlock()
@@ -3071,12 +3111,13 @@ func (t *Terminal) Loop() {
 						Loop:
 							for {
 								select {
+								case <-ctx.Done():
+									break Loop
 								case <-timer.C:
 									t.reqBox.Set(reqPreviewDelayed, version)
-								case code := <-t.killChan:
+								case immediately := <-t.killChan:
-									if code != exitCancel {
+									if immediately {
 										util.KillCommand(cmd)
-										t.eventBox.Set(EvtQuit, code)
 									} else {
 										// We can immediately kill a long-running preview program
 										// once we started rendering its partial output
@@ -3131,11 +3172,14 @@ func (t *Terminal) Loop() {
 		var focusedIndex int32 = minItem.Index()
 		var version int64 = -1
 		running := true
-		code := exitError
+		code := ExitError
 		exit := func(getCode func() int) {
+			if t.listener != nil {
+				t.listener.Close()
+			}
 			t.tui.Close()
 			code = getCode()
-			if code <= exitNoMatch && t.history != nil {
+			if code <= ExitNoMatch && t.history != nil {
 				t.history.append(string(t.input))
 			}
 			running = false
@@ -3203,9 +3247,9 @@ func (t *Terminal) Loop() {
 					case reqClose:
 						exit(func() int {
 							if t.output() {
-								return exitOk
+								return ExitOk
 							}
-							return exitNoMatch
+							return ExitNoMatch
 						})
 						return
 					case reqPreviewDisplay:
@@ -3233,11 +3277,14 @@ func (t *Terminal) Loop() {
 					case reqPrintQuery:
 						exit(func() int {
 							t.printer(string(t.input))
-							return exitOk
+							return ExitOk
 						})
 						return
 					case reqQuit:
-						exit(func() int { return exitInterrupt })
+						exit(func() int { return ExitInterrupt })
+						return
+					case reqFatal:
+						exit(func() int { return ExitError })
 						return
 					}
 				}
@@ -3245,8 +3292,11 @@ func (t *Terminal) Loop() {
 				t.mutex.Unlock()
 			})
 		}
-		// prof.Stop()
+
-		t.killPreview(code)
+		t.eventBox.Set(EvtQuit, code)
+		t.running.Set(false)
+		t.killPreview()
+		cancel()
 	}()
 
 	looping := true
@@ -3256,8 +3306,16 @@ func (t *Terminal) Loop() {
 	barrier := make(chan bool)
 	go func() {
 		for {
-			<-barrier
+			select {
-			t.eventChan <- t.tui.GetChar()
+			case <-ctx.Done():
+				return
+			case <-barrier:
+			}
+			select {
+			case <-ctx.Done():
+				return
+			case t.eventChan <- t.tui.GetChar():
+			}
 		}
 	}()
 	previewDraggingPos := -1
@@ -3353,7 +3411,7 @@ func (t *Terminal) Loop() {
 				t.pressed = ret
 				t.reqBox.Set(reqClose, nil)
 				t.mutex.Unlock()
-				return
+				return nil
 			}
 		}
 
@@ -3547,8 +3605,9 @@ func (t *Terminal) Loop() {
 				}
 			case actTransform:
 				body := t.executeCommand(a.a, false, true, true, false)
-				actions := parseSingleActionList(strings.Trim(body, "\r\n"), func(message string) {})
+				if actions, err := parseSingleActionList(strings.Trim(body, "\r\n")); err == nil {
-				return doActions(actions)
+					return doActions(actions)
+				}
 			case actTransformBorderLabel:
 				label := t.executeCommand(a.a, false, true, true, true)
 				t.borderLabelOpts.label = label
@@ -3580,6 +3639,8 @@ func (t *Terminal) Loop() {
 					t.input = current.text.ToRunes()
 					t.cx = len(t.input)
 				}
+			case actFatal:
+				req(reqFatal)
 			case actAbort:
 				req(reqQuit)
 			case actDeleteChar:
@@ -4066,15 +4127,17 @@ func (t *Terminal) Loop() {
 					t.reading = true
 				}
 			case actUnbind:
-				keys := parseKeyChords(a.a, "PANIC")
+				if keys, err := parseKeyChords(a.a, "PANIC"); err == nil {
-				for key := range keys {
+					for key := range keys {
-					delete(t.keymap, key)
+						delete(t.keymap, key)
+					}
 				}
 			case actRebind:
-				keys := parseKeyChords(a.a, "PANIC")
+				if keys, err := parseKeyChords(a.a, "PANIC"); err == nil {
-				for key := range keys {
+					for key := range keys {
-					if originalAction, found := t.keymapOrg[key]; found {
+						if originalAction, found := t.keymapOrg[key]; found {
-						t.keymap[key] = originalAction
+							t.keymap[key] = originalAction
+						}
 					}
 				}
 			case actChangePreview:
@@ -4221,6 +4284,7 @@ func (t *Terminal) Loop() {
 			t.reqBox.Set(event, nil)
 		}
 	}
+	return nil
 }
 
 func (t *Terminal) constrain() {

src/tokenizer_test.go

@@ -71,14 +71,14 @@ func TestTransform(t *testing.T) {
 	{
 		tokens := Tokenize(input, Delimiter{})
 		{
-			ranges := splitNth("1,2,3")
+			ranges, _ := splitNth("1,2,3")
 			tx := Transform(tokens, ranges)
 			if joinTokens(tx) != "abc:  def:  ghi:  " {
 				t.Errorf("%s", tx)
 			}
 		}
 		{
-			ranges := splitNth("1..2,3,2..,1")
+			ranges, _ := splitNth("1..2,3,2..,1")
 			tx := Transform(tokens, ranges)
 			if string(joinTokens(tx)) != "abc:  def:  ghi:  def:  ghi:  jklabc:  " ||
 				len(tx) != 4 ||
@@ -93,7 +93,7 @@ func TestTransform(t *testing.T) {
 	{
 		tokens := Tokenize(input, delimiterRegexp(":"))
 		{
-			ranges := splitNth("1..2,3,2..,1")
+			ranges, _ := splitNth("1..2,3,2..,1")
 			tx := Transform(tokens, ranges)
 			if joinTokens(tx) != "  abc:  def:  ghi:  def:  ghi:  jkl  abc:" ||
 				len(tx) != 4 ||
@@ -108,5 +108,6 @@ func TestTransform(t *testing.T) {
 }
 
 func TestTransformIndexOutOfBounds(t *testing.T) {
-	Transform([]Token{}, splitNth("1"))
+	s, _ := splitNth("1")
+	Transform([]Token{}, s)
 }

src/tui/dummy.go

@@ -29,7 +29,7 @@ const (
 	StrikeThrough = Attr(1 << 7)
 )
 
-func (r *FullscreenRenderer) Init()                              {}
+func (r *FullscreenRenderer) Init() error                        { return nil }
 func (r *FullscreenRenderer) Resize(maxHeightFunc func(int) int) {}
 func (r *FullscreenRenderer) Pause(bool)                         {}
 func (r *FullscreenRenderer) Resume(bool, bool)                  {}

src/tui/eventtype_string.go

@@ -83,34 +83,35 @@ func _() {
 	_ = x[Alt-72]
 	_ = x[CtrlAlt-73]
 	_ = x[Invalid-74]
-	_ = x[Mouse-75]
+	_ = x[Fatal-75]
-	_ = x[DoubleClick-76]
+	_ = x[Mouse-76]
-	_ = x[LeftClick-77]
+	_ = x[DoubleClick-77]
-	_ = x[RightClick-78]
+	_ = x[LeftClick-78]
-	_ = x[SLeftClick-79]
+	_ = x[RightClick-79]
-	_ = x[SRightClick-80]
+	_ = x[SLeftClick-80]
-	_ = x[ScrollUp-81]
+	_ = x[SRightClick-81]
-	_ = x[ScrollDown-82]
+	_ = x[ScrollUp-82]
-	_ = x[SScrollUp-83]
+	_ = x[ScrollDown-83]
-	_ = x[SScrollDown-84]
+	_ = x[SScrollUp-84]
-	_ = x[PreviewScrollUp-85]
+	_ = x[SScrollDown-85]
-	_ = x[PreviewScrollDown-86]
+	_ = x[PreviewScrollUp-86]
-	_ = x[Resize-87]
+	_ = x[PreviewScrollDown-87]
-	_ = x[Change-88]
+	_ = x[Resize-88]
-	_ = x[BackwardEOF-89]
+	_ = x[Change-89]
-	_ = x[Start-90]
+	_ = x[BackwardEOF-90]
-	_ = x[Load-91]
+	_ = x[Start-91]
-	_ = x[Focus-92]
+	_ = x[Load-92]
-	_ = x[One-93]
+	_ = x[Focus-93]
-	_ = x[Zero-94]
+	_ = x[One-94]
-	_ = x[Result-95]
+	_ = x[Zero-95]
-	_ = x[Jump-96]
+	_ = x[Result-96]
-	_ = x[JumpCancel-97]
+	_ = x[Jump-97]
+	_ = x[JumpCancel-98]
 }
 
-const _EventType_name = "RuneCtrlACtrlBCtrlCCtrlDCtrlECtrlFCtrlGCtrlHTabCtrlJCtrlKCtrlLCtrlMCtrlNCtrlOCtrlPCtrlQCtrlRCtrlSCtrlTCtrlUCtrlVCtrlWCtrlXCtrlYCtrlZEscCtrlSpaceCtrlDeleteCtrlBackSlashCtrlRightBracketCtrlCaretCtrlSlashShiftTabBackspaceDeletePageUpPageDownUpDownLeftRightHomeEndInsertShiftUpShiftDownShiftLeftShiftRightShiftDeleteF1F2F3F4F5F6F7F8F9F10F11F12AltBackspaceAltUpAltDownAltLeftAltRightAltShiftUpAltShiftDownAltShiftLeftAltShiftRightAltCtrlAltInvalidMouseDoubleClickLeftClickRightClickSLeftClickSRightClickScrollUpScrollDownSScrollUpSScrollDownPreviewScrollUpPreviewScrollDownResizeChangeBackwardEOFStartLoadFocusOneZeroResultJumpJumpCancel"
+const _EventType_name = "RuneCtrlACtrlBCtrlCCtrlDCtrlECtrlFCtrlGCtrlHTabCtrlJCtrlKCtrlLCtrlMCtrlNCtrlOCtrlPCtrlQCtrlRCtrlSCtrlTCtrlUCtrlVCtrlWCtrlXCtrlYCtrlZEscCtrlSpaceCtrlDeleteCtrlBackSlashCtrlRightBracketCtrlCaretCtrlSlashShiftTabBackspaceDeletePageUpPageDownUpDownLeftRightHomeEndInsertShiftUpShiftDownShiftLeftShiftRightShiftDeleteF1F2F3F4F5F6F7F8F9F10F11F12AltBackspaceAltUpAltDownAltLeftAltRightAltShiftUpAltShiftDownAltShiftLeftAltShiftRightAltCtrlAltInvalidFatalMouseDoubleClickLeftClickRightClickSLeftClickSRightClickScrollUpScrollDownSScrollUpSScrollDownPreviewScrollUpPreviewScrollDownResizeChangeBackwardEOFStartLoadFocusOneZeroResultJumpJumpCancel"
 
-var _EventType_index = [...]uint16{0, 4, 9, 14, 19, 24, 29, 34, 39, 44, 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97, 102, 107, 112, 117, 122, 127, 132, 135, 144, 154, 167, 183, 192, 201, 209, 218, 224, 230, 238, 240, 244, 248, 253, 257, 260, 266, 273, 282, 291, 301, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 333, 336, 339, 351, 356, 363, 370, 378, 388, 400, 412, 425, 428, 435, 442, 447, 458, 467, 477, 487, 498, 506, 516, 525, 536, 551, 568, 574, 580, 591, 596, 600, 605, 608, 612, 618, 622, 632}
+var _EventType_index = [...]uint16{0, 4, 9, 14, 19, 24, 29, 34, 39, 44, 47, 52, 57, 62, 67, 72, 77, 82, 87, 92, 97, 102, 107, 112, 117, 122, 127, 132, 135, 144, 154, 167, 183, 192, 201, 209, 218, 224, 230, 238, 240, 244, 248, 253, 257, 260, 266, 273, 282, 291, 301, 312, 314, 316, 318, 320, 322, 324, 326, 328, 330, 333, 336, 339, 351, 356, 363, 370, 378, 388, 400, 412, 425, 428, 435, 442, 447, 452, 463, 472, 482, 492, 503, 511, 521, 530, 541, 556, 573, 579, 585, 596, 601, 605, 610, 613, 617, 623, 627, 637}
 
 func (i EventType) String() string {
 	if i < 0 || i >= EventType(len(_EventType_index)-1) {

src/tui/light.go

@@ -2,6 +2,7 @@ package tui
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"os"
 	"regexp"
@@ -10,6 +11,7 @@ import (
 	"time"
 	"unicode/utf8"
 
+	"github.com/junegunn/fzf/src/util"
 	"github.com/rivo/uniseg"
 
 	"golang.org/x/term"
@@ -26,6 +28,7 @@ const (
 )
 
 const consoleDevice string = "/dev/tty"
+const fatalError string = "Failed to read " + consoleDevice
 
 var offsetRegexp *regexp.Regexp = regexp.MustCompile("(.*)\x1b\\[([0-9]+);([0-9]+)R")
 var offsetRegexpBegin *regexp.Regexp = regexp.MustCompile("^\x1b\\[[0-9]+;[0-9]+R")
@@ -78,6 +81,7 @@ func (r *LightRenderer) flush() {
 
 // Light renderer
 type LightRenderer struct {
+	closed        *util.AtomicBool
 	theme         *ColorTheme
 	mouse         bool
 	forceBlack    bool
@@ -123,19 +127,24 @@ type LightWindow struct {
 	bg       Color
 }
 
-func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop int, clearOnExit bool, fullscreen bool, maxHeightFunc func(int) int) Renderer {
+func NewLightRenderer(theme *ColorTheme, forceBlack bool, mouse bool, tabstop int, clearOnExit bool, fullscreen bool, maxHeightFunc func(int) int) (Renderer, error) {
+	in, err := openTtyIn()
+	if err != nil {
+		return nil, err
+	}
 	r := LightRenderer{
+		closed:        util.NewAtomicBool(false),
 		theme:         theme,
 		forceBlack:    forceBlack,
 		mouse:         mouse,
 		clearOnExit:   clearOnExit,
-		ttyin:         openTtyIn(),
+		ttyin:         in,
 		yoffset:       0,
 		tabstop:       tabstop,
 		fullscreen:    fullscreen,
 		upOneLine:     false,
 		maxHeightFunc: maxHeightFunc}
-	return &r
+	return &r, nil
 }
 
 func repeat(r rune, times int) string {
@@ -153,11 +162,11 @@ func atoi(s string, defaultValue int) int {
 	return value
 }
 
-func (r *LightRenderer) Init() {
+func (r *LightRenderer) Init() error {
 	r.escDelay = atoi(os.Getenv("ESCDELAY"), defaultEscDelay)
 
 	if err := r.initPlatform(); err != nil {
-		errorExit(err.Error())
+		return err
 	}
 	r.updateTerminalSize()
 	initTheme(r.theme, r.defaultTheme(), r.forceBlack)
@@ -195,6 +204,7 @@ func (r *LightRenderer) Init() {
 	if !r.fullscreen && r.mouse {
 		r.yoffset, _ = r.findOffset()
 	}
+	return nil
 }
 
 func (r *LightRenderer) Resize(maxHeightFunc func(int) int) {
@@ -233,15 +243,16 @@ func getEnv(name string, defaultValue int) int {
 	return atoi(env, defaultValue)
 }
 
-func (r *LightRenderer) getBytes() []byte {
+func (r *LightRenderer) getBytes() ([]byte, error) {
-	return r.getBytesInternal(r.buffer, false)
+	bytes, err := r.getBytesInternal(r.buffer, false)
+	return bytes, err
 }
 
-func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) []byte {
+func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) ([]byte, error) {
 	c, ok := r.getch(nonblock)
 	if !nonblock && !ok {
 		r.Close()
-		errorExit("Failed to read " + consoleDevice)
+		return nil, errors.New("Failed to read " + consoleDevice)
 	}
 
 	retries := 0
@@ -272,19 +283,23 @@ func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) []byte {
 		// so terminate fzf immediately.
 		if len(buffer) > maxInputBuffer {
 			r.Close()
-			panic(fmt.Sprintf("Input buffer overflow (%d): %v", len(buffer), buffer))
+			return nil, fmt.Errorf("Input buffer overflow (%d): %v", len(buffer), buffer)
 		}
 	}
 
-	return buffer
+	return buffer, nil
 }
 
 func (r *LightRenderer) GetChar() Event {
+	var err error
 	if len(r.buffer) == 0 {
-		r.buffer = r.getBytes()
+		r.buffer, err = r.getBytes()
+		if err != nil {
+			return Event{Fatal, 0, nil}
+		}
 	}
 	if len(r.buffer) == 0 {
-		panic("Empty buffer")
+		return Event{Fatal, 0, nil}
 	}
 
 	sz := 1
@@ -315,7 +330,10 @@ func (r *LightRenderer) GetChar() Event {
 		ev := r.escSequence(&sz)
 		// Second chance
 		if ev.Type == Invalid {
-			r.buffer = r.getBytes()
+			r.buffer, err = r.getBytes()
+			if err != nil {
+				return Event{Fatal, 0, nil}
+			}
 			ev = r.escSequence(&sz)
 		}
 		return ev
@@ -738,6 +756,7 @@ func (r *LightRenderer) Close() {
 	r.flush()
 	r.closePlatform()
 	r.restoreTerminal()
+	r.closed.Set(true)
 }
 
 func (r *LightRenderer) Top() int {

src/tui/light_unix.go

@@ -3,7 +3,7 @@
 package tui
 
 import (
-	"fmt"
+	"errors"
 	"os"
 	"os/exec"
 	"strings"
@@ -48,19 +48,18 @@ func (r *LightRenderer) closePlatform() {
 	// NOOP
 }
 
-func openTtyIn() *os.File {
+func openTtyIn() (*os.File, error) {
 	in, err := os.OpenFile(consoleDevice, syscall.O_RDONLY, 0)
 	if err != nil {
 		tty := ttyname()
 		if len(tty) > 0 {
 			if in, err := os.OpenFile(tty, syscall.O_RDONLY, 0); err == nil {
-				return in
+				return in, nil
 			}
 		}
-		fmt.Fprintln(os.Stderr, "Failed to open "+consoleDevice)
+		return nil, errors.New("Failed to open " + consoleDevice)
-		util.Exit(2)
 	}
-	return in
+	return in, nil
 }
 
 func (r *LightRenderer) setupTerminal() {
@@ -86,9 +85,14 @@ func (r *LightRenderer) updateTerminalSize() {
 func (r *LightRenderer) findOffset() (row int, col int) {
 	r.csi("6n")
 	r.flush()
+	var err error
 	bytes := []byte{}
 	for tries := 0; tries < offsetPollTries; tries++ {
-		bytes = r.getBytesInternal(bytes, tries > 0)
+		bytes, err = r.getBytesInternal(bytes, tries > 0)
+		if err != nil {
+			return -1, -1
+		}
+
 		offsets := offsetRegexp.FindSubmatch(bytes)
 		if len(offsets) > 3 {
 			// Add anything we skipped over to the input buffer

src/tui/light_windows.go

@@ -72,7 +72,7 @@ func (r *LightRenderer) initPlatform() error {
 	go func() {
 		fd := int(r.inHandle)
 		b := make([]byte, 1)
-		for {
+		for !r.closed.Get() {
 			// HACK: if run from PSReadline, something resets ConsoleMode to remove ENABLE_VIRTUAL_TERMINAL_INPUT.
 			_ = windows.SetConsoleMode(windows.Handle(r.inHandle), consoleFlagsInput)
 
@@ -91,9 +91,9 @@ func (r *LightRenderer) closePlatform() {
 	windows.SetConsoleMode(windows.Handle(r.inHandle), r.origStateInput)
 }
 
-func openTtyIn() *os.File {
+func openTtyIn() (*os.File, error) {
 	// not used
-	return nil
+	return nil, nil
 }
 
 func (r *LightRenderer) setupTerminal() error {

src/tui/tcell.go

@@ -7,7 +7,6 @@ import (
 	"time"
 
 	"github.com/gdamore/tcell/v2"
-	"github.com/gdamore/tcell/v2/encoding"
 	"github.com/junegunn/fzf/src/util"
 
 	"github.com/rivo/uniseg"
@@ -146,13 +145,13 @@ var (
 	_initialResize   bool = true
 )
 
-func (r *FullscreenRenderer) initScreen() {
+func (r *FullscreenRenderer) initScreen() error {
 	s, e := tcell.NewScreen()
 	if e != nil {
-		errorExit(e.Error())
+		return e
 	}
 	if e = s.Init(); e != nil {
-		errorExit(e.Error())
+		return e
 	}
 	if r.mouse {
 		s.EnableMouse()
@@ -160,16 +159,21 @@ func (r *FullscreenRenderer) initScreen() {
 		s.DisableMouse()
 	}
 	_screen = s
+
+	return nil
 }
 
-func (r *FullscreenRenderer) Init() {
+func (r *FullscreenRenderer) Init() error {
 	if os.Getenv("TERM") == "cygwin" {
 		os.Setenv("TERM", "")
 	}
-	encoding.Register()
 
-	r.initScreen()
+	if err := r.initScreen(); err != nil {
+		return err
+	}
 	initTheme(r.theme, r.defaultTheme(), r.forceBlack)
+
+	return nil
 }
 
 func (r *FullscreenRenderer) Top() int {

src/tui/tui.go

@@ -1,8 +1,6 @@
 package tui
 
 import (
-	"fmt"
-	"os"
 	"strconv"
 	"time"
 
@@ -104,6 +102,7 @@ const (
 	CtrlAlt
 
 	Invalid
+	Fatal
 
 	Mouse
 	DoubleClick
@@ -525,7 +524,7 @@ type TermSize struct {
 }
 
 type Renderer interface {
-	Init()
+	Init() error
 	Resize(maxHeightFunc func(int) int)
 	Pause(clear bool)
 	Resume(clear bool, sigcont bool)
@@ -685,11 +684,6 @@ func NoColorTheme() *ColorTheme {
 	}
 }
 
-func errorExit(message string) {
-	fmt.Fprintln(os.Stderr, message)
-	util.Exit(2)
-}
-
 func init() {
 	Default16 = &ColorTheme{
 		Colored:          true,

src/util/atexit.go

@@ -25,6 +25,7 @@ func RunAtExitFuncs() {
 	for i := len(fns) - 1; i >= 0; i-- {
 		fns[i]()
 	}
+	atExitFuncs = nil
 }
 
 // Exit executes any functions registered with AtExit() then exits the program