Crash in program due to deadlock

[joegrasse]

This example program crashes when doing a CTR-C.

fatal error: all goroutines are asleep - deadlock!

goroutine 1 [select]:
github.com/rivo/tview.(*Application).Run(0xc00017c000, 0x0, 0x0)
        C:/Users/user/Documents/gowork/pkg/mod/github.com/rivo/tview@v0.0.0-20210217110421-8a8f78a6dd01/application.go:302 +0x205
main.main()
        C:/Users/user/Documents/gowork/src/github.com/user/box/main.go:17 +0x1e5

goroutine 19 [select]:
github.com/gdamore/tcell/v2.(*cScreen).PollEvent(0xc00017e000, 0xc000049fa0, 0xc0002b85e0)
        C:/Users/user/Documents/gowork/pkg/mod/github.com/gdamore/tcell/v2@v2.2.0/console_win.go:372 +0xbf
github.com/rivo/tview.(*Application).Run.func2(0xc0000b1690, 0xc00017c000)
        C:/Users/user/Documents/gowork/pkg/mod/github.com/rivo/tview@v0.0.0-20210217110421-8a8f78a6dd01/application.go:267 +0xac
created by github.com/rivo/tview.(*Application).Run
        C:/Users/user/Documents/gowork/pkg/mod/github.com/rivo/tview@v0.0.0-20210217110421-8a8f78a6dd01/application.go:254 +0x11d

C:\WINDOWS\system32>

main.go

// Demo code for the Box primitive.
package main

import (
	"github.com/gdamore/tcell/v2"
	"github.com/rivo/tview"
)

func main() {
	box := tview.NewBox().
		SetBackgroundColor(tcell.ColorGreen).
		SetTitle("Hello").
		SetBorder(true).
		SetBorderPadding(0, 0, 0, 0).
		SetBorderColor(tcell.ColorWhite)

	if err := tview.NewApplication().SetRoot(box, true).Run(); err != nil {
		panic(err)
	}
}

go.mod

module github.com/joegrasse/box

go 1.15

require (
	github.com/gdamore/tcell/v2 v2.2.0
	github.com/rivo/tview v0.0.0-20210217110421-8a8f78a6dd01
)

go.sum

github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdko=
github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
github.com/gdamore/tcell v1.4.0 h1:vUnHwJRvcPQa3tzi+0QI4U9JINXYJlOz9yiaiPQ2wMU=
github.com/gdamore/tcell/v2 v2.0.1-0.20201017141208-acf90d56d591/go.mod h1:vSVL/GV5mCSlPC6thFP5kfOFdM9MGZcalipmpTxTgQA=
github.com/gdamore/tcell/v2 v2.2.0 h1:vSyEgKwraXPSOkvCk7IwOSyX+Pv3V2cV9CikJMXg4U4=
github.com/gdamore/tcell/v2 v2.2.0/go.mod h1:cTTuF84Dlj/RqmaCIV5p4w8uG1zWdk0SF6oBpwHp4fU=
github.com/lucasb-eyer/go-colorful v1.0.3 h1:QIbQXiugsb+q10B+MI+7DI1oQLdmnep86tWFlaaUAac=
github.com/lucasb-eyer/go-colorful v1.0.3/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
github.com/mattn/go-runewidth v0.0.7/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
github.com/mattn/go-runewidth v0.0.10 h1:CoZ3S2P7pvtP45xOtBw+/mDL2z0RKI576gSkzRRpdGg=
github.com/mattn/go-runewidth v0.0.10/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
github.com/rivo/tview v0.0.0-20210217110421-8a8f78a6dd01 h1:rtCzDXdaqhiRakJsz0bUj+3sOUjw82bJDcJrAzQ0u+M=
github.com/rivo/tview v0.0.0-20210217110421-8a8f78a6dd01/go.mod h1:n2q/ydglZJ1kqxiNrnYO+FaX1H14vA0wKyIo953QakU=
github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210113181707-4bcb84eeeb78 h1:nVuTkr9L6Bq62qpUqKo/RnZCFfzDBL0bYo6w9OJUqZY=
golang.org/x/sys v0.0.0-20210113181707-4bcb84eeeb78/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf h1:MZ2shdL+ZM/XzY3ZGOnh4Nlpnxz5GSOhOmtHo3iPU6M=
golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.5 h1:i6eZZ+zk0SOf0xgBpEpPD18qWcJda6q1sxt3S0kzyUQ=
golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

[rivo]

I'm a bit confused because you appear to be using commit 8a8f78a6dd01dd45a16f940155a4bcc296dfd6bc of tview but with a different go.mod file, see there actual file:

tview/go.mod

Lines 5 to 12 in 8a8f78a

	require (
	github.com/gdamore/tcell/v2 v2.0.1-0.20201017141208-acf90d56d591
	github.com/lucasb-eyer/go-colorful v1.0.3
	github.com/mattn/go-runewidth v0.0.10
	github.com/rivo/uniseg v0.2.0
	golang.org/x/sys v0.0.0-20210113181707-4bcb84eeeb78 // indirect
	golang.org/x/text v0.3.5 // indirect
	)

Specifically, the tcell version in your go.mod file is a different one. Did you create your own go.mod file?

[joegrasse]

No. Here is what I did.

1. Made sure I didn't have tcell or tview in my $GOPATH src dir.
2. Created new project folder
3. Created main.go
4. Ran go mod init
5. Ran go install

[joegrasse]

As a test, I pinned tcell to the version you stated above by setting the go.mod to the following, and rebuilt. My app didn't crash when doing a CTR-C.

module github.com/joegrasse/box

go 1.15

require (
	github.com/gdamore/tcell/v2 v2.0.1-0.20201017141208-acf90d56d591
	github.com/rivo/tview v0.0.0-20210217110421-8a8f78a6dd01
)

[rivo]

In my previous comment, I didn't realize this was the go.mod file of your program, not tview. But I think it should have still imported the correct tcell version. I don't know why it didn't.

In the meantime, I upgraded tcell to the latest version in tview (which is the one you used in the first place) but still couldn't reproduce the error. So it's a bit odd that this is happening.

In any case, I understand that you also can't reproduce it anymore?

[joegrasse]

I can still reproduce it if i switch my go.mod back.

What was happening with my program was go was importing the most recent version of tcell, which is v2.2.0. So there is an incompatibility when my program uses tcell v2.2.0 with version v0.0.0-20210217110421-8a8f78a6dd01 of tview.

I can upgrade to your most recent version of tview and see if it still happens.

[joegrasse]

With the most recent version of tview and tcell, I am still able to reproduce the error.

go.mod

module github.com/joegrasse/box

go 1.15

require (
	github.com/gdamore/tcell/v2 v2.2.0
	github.com/rivo/tview v0.0.0-20210312115847-ae065beb933c
)

go.sum

github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdko=
github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
github.com/gdamore/tcell v1.4.0 h1:vUnHwJRvcPQa3tzi+0QI4U9JINXYJlOz9yiaiPQ2wMU=
github.com/gdamore/tcell/v2 v2.2.0 h1:vSyEgKwraXPSOkvCk7IwOSyX+Pv3V2cV9CikJMXg4U4=
github.com/gdamore/tcell/v2 v2.2.0/go.mod h1:cTTuF84Dlj/RqmaCIV5p4w8uG1zWdk0SF6oBpwHp4fU=
github.com/lucasb-eyer/go-colorful v1.0.3/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
github.com/mattn/go-runewidth v0.0.10 h1:CoZ3S2P7pvtP45xOtBw+/mDL2z0RKI576gSkzRRpdGg=
github.com/mattn/go-runewidth v0.0.10/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
github.com/rivo/tview v0.0.0-20210312115847-ae065beb933c h1:eNIEQTOdI8dIlu809N3vS4vB1l/EEc/B8fHAgu7nGN0=
github.com/rivo/tview v0.0.0-20210312115847-ae065beb933c/go.mod h1:N/me/Wl2SRS18qi3TyvXbciIPyNwljilmybxouFxEuk=
github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/sys v0.0.0-20210309074719-68d13333faf2 h1:46ULzRKLh1CwgRq2dC5SlBzEqqNCi8rreOZnNrbqcIY=
golang.org/x/sys v0.0.0-20210309074719-68d13333faf2/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
golang.org/x/term v0.0.0-20201210144234-2321bbc49cbf/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d h1:SZxvLBoTP5yHO3Frd4z4vrF+DBX9vMVanchswa69toE=
golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
golang.org/x/text v0.3.5 h1:i6eZZ+zk0SOf0xgBpEpPD18qWcJda6q1sxt3S0kzyUQ=
golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

fatal error: all goroutines are asleep - deadlock!

goroutine 1 [select]:
github.com/rivo/tview.(*Application).Run(0xc00017c000, 0x0, 0x0)
        C:/Users/user/Documents/gowork/pkg/mod/github.com/rivo/tview@v0.0.0-20210312115847-ae065beb933c/application.go:302 +0x205
main.main()
        C:/Users/user/Documents/gowork/src/github.com/joegrasse/box/main.go:17 +0x1e5

goroutine 19 [select]:
github.com/gdamore/tcell/v2.(*cScreen).PollEvent(0xc00017e000, 0xc000049fa0, 0xc0003ead40)
        C:/Users/user/Documents/gowork/pkg/mod/github.com/gdamore/tcell/v2@v2.2.0/console_win.go:372 +0xbf
github.com/rivo/tview.(*Application).Run.func2(0xc0000cbf50, 0xc00017c000)
        C:/Users/user/Documents/gowork/pkg/mod/github.com/rivo/tview@v0.0.0-20210312115847-ae065beb933c/application.go:267 +0xac
created by github.com/rivo/tview.(*Application).Run
        C:/Users/user/Documents/gowork/pkg/mod/github.com/rivo/tview@v0.0.0-20210312115847-ae065beb933c/application.go:254 +0x11d

[rivo]

I just used exactly the same configuration as you but still didn't get a panic. But I'm on macOS. What OS and shell are you using?

[joegrasse]

I am on windows 10 and cmd.exe.

[joegrasse]

I have tested this on linux and it doesn't crash with the same error. So this is windows code path specific.

[joegrasse]

After looking into this more, it looks like the problem is a change in behavior of tcell. In v1 of tcell, Fini would call a section of code that would close(s.quit). In v2 of tcell, Fini now calls disengage (see that here). The code that was called to close the s.quit channel is now buried in a new private function finish (see that here). So PollEvent doesn't return. So both tview and tcell are waiting for something to happen.

I am not sure if this is a bug in tcell, where it should also be calling finish after disengage, or if this is a bug in the use of tcell v2.

\cc @rivo @gdamore

[joegrasse]

This might be fixed in tcell v2.2.1. Can you upgrade to that version?

[rivo]

I upgraded to the latest version. Does it work for you now?

[joegrasse]

Yes, it works now. Thanks.

[rivo]

Great! Thanks for the feedback.