Use command -v to detect git

[radar]

Version details:

Version: 1.39.1
Commit: 88f15d17dca836346e787762685a40bb5cce75a8
Date: 2019-10-10T23:35:11.314Z
Electron: 4.2.10
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Darwin x64 18.7.0

What I expect to happen

VS Code's Git extension finds + uses Git

What actually happens

VS Code says it cannot find Git:

Steps to reproduce

TL;DR: VS Code should use command -v to detect commands, not which.

This is a bit tricky, so bear with me:

There is a node package called which:

https://www.npmjs.com/package/which

If this package is installed through Node, and a user is using asdf, this which-from-node can take precedence in $PATH. This will cause issues if there is no default Node version specified for asdf. An error like this can appear:

asdf: No version set for command which
you might want to add one of the following in your .tool-versions file:

nodejs 8.14.0

(I suspect this is only an issue on 'zsh' terminals -- I am unable to reproduce it in Bash)

To work around this which-conflict, we should use the built-in 'command' command. This comes standard in every shell program and is a viable alternative to 'which'.

When my shell works correctly, here's the output of which -a which:

which: shell built-in command
/Users/ryanbigg/.asdf/shims/which
/usr/bin/which

However, when it is misbehaving, I suspect the order is like this:

/Users/ryanbigg/.asdf/shims/which
which: shell built-in command
/usr/bin/which

And that's why it's trying to use the node which. When no node version is configured for asdf, then it fails to run that node-which, which then causes this extension to claim that it can't find git.

This PR (likely) fixes #81287 -- although I'm not 100% sure of that.

[JoshTeperman]

👀

[joaomoreno]

So... what happens if the user has a command command ahead in their PATH variable, just like which?

[joaomoreno]

Closing.

[ryenus]

So... what happens if the user has a command command ahead in their PATH variable, just like which?

I believe that wouldn't be a problem because the shell builtin command should take precedence over things from $PATH.

From bash manual: Shell Builtin Commands

When the name of a builtin command is used as the first word of a simple command (see Simple Commands), the shell executes the command directly, without invoking another program.

[joaomoreno]

Isn't which a builtin command, as was mentioned above?

[ryenus]

Isn't which a builtin command, as was mentioned above?

In csh which is indeed a builtin, but not in sh/bash, @joaomoreno

[joaomoreno]

Got it. Keeping my opinion: this is not worth the trouble.