Yarn: Yarn init fails on Windows under Git bash / MinGW / Cygwin

[lewiswalsh]

Under Git Bash on Windows when entering 'yarn init' I get the following error:

error Can't answer a question unless a user TTY
at ConsoleReporter.question (C:\Program Files (x86)\Yarn\lib\reporters\console\console-reporter.js:189:29)
at Object. (C:\Program Files (x86)\Yarn\lib\cli\commands\init.js:91:38)
at next (native)
at step (C:\Program Files (x86)\Yarn\node_modules\babel-runtime\helpersasyncToGenerator.js:17:30)
at C:\Program Files (x86)\Yarn\node_modules\babel-runtime\helpersasyncToGenerator.js:28:20
at run (C:\Program Files (x86)\Yarn\node_modules\core-js\library\modules\es6.promise.js:87:22)
at C:\Program Files (x86)\Yarn\node_modules\core-js\library\modules\es6.promise.js:100:28
at flush (C:\Program Files (x86)\Yarn\node_modules\core-js\library\modules_microtask.js:18:9)
at _combinedTickCallback (internal/process/next_tick.js:67:7)
at process._tickCallback (internal/process/next_tick.js:98:9)

Other yarn commands seem to work as expected.

Yarn v0.15.1
Node v6.0.0
Windows 10 Pro 1607

[Daniel15]

Seems like this is an issue with Cygwin and MinGW in that they're not 'proper' TTYs: https://github.com/nodejs/node/issues/3006

I don't think we can fix this at our end.

[oliversalzburg]

Well, one thing you could do would be to remove the check ;)

In all seriousness though. It is my understanding that the check is in place because you're trying to make sure that the I/O scenario that is about to happen will work. Does that check actually achieve this? Will the scenario actually fail in MinGW? If not, then a different check should be performed or it should be omitted completely IMHO.

[Daniel15]

My understanding is that the check is to stop the process hanging indefinitely when not using a TTY (for example, if running as part of a build process that pipes stdin and stdout). In theory, if there's no TTY, there's no way to accept input. May be the check should "if it's a TTY or if it's MinGW" to handle this case specifically? I think that'd fail if you try to pipe the output to a file when running under MinGW though (it'd hang).

[jdalton]

FWIW the yarn master branch works with

• [x] WSL
• [x] MINGW32
• [ ] Git Bash
• [ ] Cygwin

npm init works in Git Bash, Cygwin, WSL, & MINGW32.

[Daniel15]

Yeah, I just noticed that npm init is fine. Sounds like we should take a look at how npm is handling it 😄

[oliversalzburg]

Sounds like we should take a look at how npm is handling it

They're simply not enforcing isTTY.

[Daniel15]

Ahh, that's an interesting approach @oliversalzburg. I guess it means trying to run it in a script would result in the script "freezing" as it sits waiting for user input. Not ideal 😕

Maybe we could do that just for Git Bash and Cygwin - Only check isTTY on platforms that properly support it

[oliversalzburg]

So on the one side you have the users who, for some reason, try to run a command that requires user interaction in a script, which will now fail loudly and would otherwise fail silently and on the other side you have everyone who uses a somewhat popular terminal on Windows and is unable to use the command.

I really don't see why this is a hard choice or why it would need even more complicated terminal detection code to solve. The check is counter productive and should be removed. Slapping more prone-to-error code on top is not the solution.

That being said, I really don't care one way or the other, as there are other terminal emulators that run Git Bash which are not affected by this "problem". I would suggest that everyone who runs into this should have a look at ConEmu.

[maybeec]

I also face this issue, so I run node -p -e "Boolean(process.stdout.isTTY)" on git-bash as well as on windows cmd. Both return true, which does not fit to the behavior of git-bash and cmd as discussed here, right? Or is there anything I misunderstood regarding the isTTY discussion?
If my assumption is right, this will point the finger again to Yarn.

Yarn version:
0.16.1
Node version:
4.4.5
Platform:
Win7 x64
Trace:

Error: Can't answer a question unless a user TTY at ConsoleReporter.question (C:\Program Files (x86)\Yarn\lib\reporters\console\console-reporter.js:186:29)```

[maybeec]

btw. same for nodejs 6.9.1

[ghost]

How is this going ?
Still working on this ? I'm facing this issue at the moment.

[karlpatrickespiritu]

Hope this will be fixed soon.

[thetrompf]

I really don't get why it fails, yarn uses the "proper" way for testing this in https://github.com/yarnpkg/yarn/blob/7fe2e53a59d5c5d256459854dd7ad4d4ff874682/src/reporters/console/console-reporter.js#L173

by testing for process.stdout.isTTY

I'm using minTTY which is bundled in Git for Windows along side with Git bash as well.

Node: v7.2.1
Yarn: v0.17.10

bkc@DESKTOP-NNSLT74 ~ $ node
> process.stdout.isTTY
true
>
(To exit, press ^C again or type .exit)
>
bkc@DESKTOP-NNSLT74 ~ $ cd workspace/ts-test/
bkc@DESKTOP-NNSLT74 ~/workspace/ts-test (master) $ yarn init
yarn init v0.17.10
error An unexpected error occurred: "Can't answer a question unless a user TTY".
info If you think this is a bug, please open a bug report with the information provided in "C:\\Users\\bkc\\workspace\\ts-test\\yarn-error.log".
info Visit https://yarnpkg.com/en/docs/cli/init for documentation about this command.
bkc@DESKTOP-NNSLT74 ~/workspace/ts-test (master) $

[thetrompf]

Interestingly enough, if I install yarn as a dependency, to a project

yarn add yarn

and in invoke yarn via node and yarn.js it works fine.

node ./node_modules/yarn/bin/yarn.js init
yarn init v0.17.10
question name (yarn-test):

So it must have something to do with the native windows version?

[thetrompf]

Now it gets really weird, if I omit the node part, and try to invoke

./node_modules/yarn/bin/yarn.js init

as an executable, it fails.

[Daniel15]

@thetrompf

So it must have something to do with the native windows version?

It's possible - Running "yarn" on Windows actually goes through either a batch file (when using a regular terminal like cmd.exe, Cmder, etc) or a shell script (when using something Bash-based like MinGW, Cygwin, etc). If you installed to the default location, it's at C:\Program Files (x86)\Yarn\bin\yarn.cmd.

[ArtistsTechGuy]

I fixed this by updating my git for windows to the latest version, it looks to be a problem with winpty.exe I also updated to the latest nightly version of yarn v0.20.0 as there was a patch concerning this applied in version 0.19.

node.js - v6.9.4 | yarn - v0.20.0-20170117.1018 | git for windows - 2.11.0.3 with MinGW teminal

[JaysQubeXon]

I second with ArtistsTechGuy, upgrading to latest versions solved the issue.

[astudio8]

Even upgrading Git to the latest version, it fails for me:

yarn init (yarn 0.24.5)
error An unexpected error occurred: "Can't answer a question unless a user TTY".

[ilatypov]

Cygwin's mintty returns false to node -p -e "Boolean(process.stdout.isTTY)".

I wonder if this stalls compound scripts such as "build": "yarn run clean && yarn cover". I see a process tree with the last command stuck in the destructor of node.exe's v8::Unlocker, with our clean script defined as "clean": "rimraf ./reports",

• ..node.exe ..yarn.js run build
• 
  
  • ..cmd.exe /d /s /c yarn run clean && yarn cover
  
  
• - - node ..yarn.js run clean

[rofrol]

I got the same error as @astudio8

$ yarn init
yarn init v0.24.5
error An unexpected error occurred: "Can't answer a question unless a user TTY".
info If you think this is a bug, please open a bug report with the information provided in "C:\\projects_personal\\react\\hyperscript-helpers-elm-like\\yarn-error.log".
info Visit https://yarnpkg.com/en/docs/cli/init for documentation about this command.

$ git version
git version 2.13.0.windows.1

Windows 10

[lvlirko]

Git Bash error ..
$ yarn init yarn init v0.24.6 error An unexpected error occurred: "Can't answer a question unless a user TTY".
$ git --version 2.13.1.windows.2

---

Good thing is, Windows PowerShell works without errors.

[aimergenge]

Is there any solution now?
I has been waiting for this to fix since a long time ago.

[ScottyFillups]

I think I have a solution. Add the following to your .bashrc file:

alias yarn='node "C:\Program Files (x86)\Yarn\bin\yarn.js"'

Running yarn init should work now, maybe, hopefully... It works on my PC, at least.

[andreysobal]

I had the same problem.
When use Git Bash under console emulator ConEmu, this problem don't arise.

[lsvidal]

As previously stated in this thread, the problem is TTY handling in git-bash. So successfully ran 'yarn upgrade-interactive' using 'winpty yarn.CMD upgrade-interactive' and latter aliased yarn to 'winpty yarn.CMD' in .bashrc

[jmathew]

I think it's worth noting that sometimes you want winpty and sometimes you dont. Though in 90% cases you're safe with it prefixed.

From what I can tell it boils down to:

Action | Such as? | Prefix with winpty?
--------|----------------------| ----
Using yarn inside a pipe? | yarn.cmd --version \| cat | No
Using an interactive yarn command? | yarn.cmd init | Yes
Doing something outside a pipe and not interactive? | yarn.cmd install yarn.cmd add | Doesn't matter

$ winpty yarn.cmd init
yarn init v1.0.2
error An unexpected error occurred: "canceled".
info If you think this is a bug, please open a bug report with the information provided in 

$ yarn.cmd init
yarn init v1.0.2
error An unexpected error occurred: "Can't answer a question unless a user TTY".
info If you think this is a bug, please open a bug report with the information provided in 

$ winpty yarn.cmd --version
1.0.2

$ winpty yarn.cmd --version |cat
stdout is not a tty

$ yarn.cmd --version | cat
1.0.2

[thetrompf]

@jmathew see my pull request, which tries to fix this #4577

[jmathew]

@thetrompf I haven't tested it but the script change makes sense. Thanks!

[naguibihab]

To me this was a pretty silly issue, yarn init or yarn login wouldn't work on git bash that gets installed with git for windows but they'd work on standard cmd