--jobs=0 no longer does any work

[drewnoakes]

• I was not able to find an open or closed issue matching what I'm seeing

(Note that I did report this on the git mailing list here, but no response was received.)

Setup

• Which version of Git for Windows are you using? Is it 32-bit or 64-bit?

$ git --version --build-options

git version 2.39.2.windows.1
cpu: x86_64
built from commit: a82fa99b36ddfd643e61ed45e52abe314687df67
sizeof-long: 4
sizeof-size_t: 8
shell-path: /bin/sh
feature: fsmonitor--daemon

• Which version of Windows are you running? Vista, 7, 8, 10? Is it 32-bit or 64-bit?

$ cmd.exe /c ver

Microsoft Windows [Version 10.0.22621.1265]

• What options did you set as part of the installation? Or did you choose the
  defaults?

Editor Option: VIM
Custom Editor Path:
Default Branch Option: main
Path Option: Cmd
SSH Option: OpenSSH
Tortoise Option: false
CURL Option: OpenSSL
CRLF Option: CRLFAlways
Bash Terminal Option: MinTTY
Git Pull Behavior Option: FFOnly
Use Credential Manager: Enabled
Performance Tweaks FSCache: Enabled
Enable Symlinks: Disabled
Enable Pseudo Console Support: Disabled
Enable FSMonitor: Disabled

• Any other interesting things about your environment that might be related
  to the issue you're seeing?

Not that I know of.

Details

• Which terminal/shell are you running Git from?

Git Bash

• What commands did you run to trigger this issue? If you can provide a
  Minimal, Complete, and Verifiable example
  this will help us understand the issue.

git fetch --jobs=0

• What did you expect to occur after running these commands?

Fetches from my multiple remotes to occur concurrently.

• What actually happened instead?

Nothing was fetched.

Yesterday, nothing was logged. Today I see an error message (no idea what changed):

BUG: run-command.c:1521: you must provide a non-zero number of processes!

Note also:

• The git-config documentation says of zero jobs in "fetch.parallel" that "A value of 0 will give some reasonable default. If unset, it defaults to 1.".

• This started happening after I updated my version of Git for Windows earlier today.

• Excluding the --jobs argument or passing a non-zero value works as expected.

• If the problem was occurring with a specific repository, can you provide the
  URL to that repository to help us with testing?

Doesn't seem related to a specific repo.

[rimrul]

For completeness: This has also been reported on the mailing list.

run-command.c:1521

Ok, that's a starting point where to look.
And bingo. A blame on run-command.c:L1521 tells us it was last changed in 51243f9.

Looks like Ævar added the online_cpus() fallback in fetch.c for fetch.parallel, but missed --jobs=0. I'll try to write a fix in the next few days.

[dscho]

@rimrul since you seem to be almost there anyway, I added you as assignee, okay?

[rimrul]

since you seem to be almost there anyway, I added you as assignee, okay?

yes. I've submitted the patch to the mailing list.

[rimrul]

The fix has not made it in time for Git 2.40.0-rc0, but will be part of 2.40.0-rc1.