doc: readline on "Git Bash" - winpty required

[starkwang]

• Version: master
• Platform: Windows7, Git Bash
• Subsystem: readline

On Windows7, the Node.js application don't terminate after rl.close() :

const readline = require('readline');
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});
rl.close();

It causes test/parallel/test-readline-interface.js TIMEOUT, which will not happen in v6.x.x

[vsemozhetbyt]

FWIW, I can not reproduce the issue on Windows with v4, v6, v8 or v9.

[starkwang]

This only happens in Git Bash.
In PowerShell or cmd, It's fine.

[vsemozhetbyt]

cc @nodejs/platform-windows, @addaleax, @Fishrock123

[tniessen]

I can repoduce this. A similar and probably related problem occurs when executing node.exe without arguments, which should normally start the built-in repl, but does not under Git Bash. node.exe -i starts the repl, so I assume the console / tty configuration does not work correctly in Git Bash.

[vsemozhetbyt]

Someone told me Node.js supported building only with cmd.exe on Windows. I am not sure if we support test runs in other shells or work in other shells at all(

[joaocgreis]

This looks like a duplicate of #5620 .

Please always use winpty when running Node on Git Bash. Actually, if you run just node, Git Bash will add winpty for you. But if you run node.exe, a different file name or with a path, you have to use winpty. Try:

winpty node.exe script.js

[refack]

Please always use winpty when running Node on Git Bash.

So I'd suggest we document this, but also disclaim official support (Experimental / YMMV) for: Git Bash / MSYS / MinGW / Cygwin / WSL

[seishun]

Your test case is effectively:

process.stdin.resume();
process.stdin.pause();

When running in Git Bash, GetFileType on stdin returns FILE_TYPE_PIPE rather than FILE_TYPE_CHAR. Consequently, Node.js doesn't consider it a TTY and sets its highWaterMark to the default value of 16384, rather than 0 as in cmd.

Once you're resumed a stream, it will read until it has read highWaterMark bytes or EOF. Pausing only takes action after a chunk is read. So in your case, the process will exit once you enter 16384 bytes or EOF.

I say we close this since Git Bash is not supported. We can create a separate issue for documentation.

[refack]

I say we close this since Git Bash is not supported. We can create a separate issue for documentation.

I kinda already turned this to a documentation issue 😊, I say keep this open...

[yamalight]

@refack @starkwang I could document that. Can you please point me as to where that would need to be added?

[yamalight]

The only place that mentions platform support seems to be node/deps/uv/SUPPORTED_PLATFORMS.md - would that be the right place to add this info?

[gibfahn]

@yamalight the place we document our platform support is here: https://github.com/nodejs/node/blob/master/BUILDING.md#supported-platforms-1

Not sure what @refack had in mind, but I'd assume something like adding a note2 to the Windows section to say that running through cmd is supported, but running through any other shell is experimental (and then mention winpty for Git Bash and Cygwin).

[yamalight]

@gibfahn thanks, got it. Will make a PR soon 👍

[yamalight]

PR created. Please let me know if you want any changes.