Re: Bugreport - submodules are fetched twice in some cases

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 29, 2022, 17:39 UTC
Message-ID: <xmqqczgzdc1r.fsf@gitster.g>
In-Reply-To: <CAN8jHOgwVF5g=jM_KYT0Oh+j+Lk3qvdyA4zNRbzf8e1Xp5WAUw@mail.gmail.com>

A simple and concrete reproduction

    git init top
    cd top
    date >file1
    git init sub
    cd sub
    date >subfile1
    git add .
    git commit -m subinitial
    cd .. ;# back to top
    git submodule add ./sub sub
    git add file1
    git commit -m initial
    cd .. ;# out of top
    git clone --recurse-submodules top copy
    cd copy
    git config submodule.recurse true
    git config fetch.parallel 0
    GIT_TRACE2=$(pwd)/trace git fetch --all --prune --prune-tags

This throws the three lines to the output.

Fetching origin Fetching submodule sub Fetching submodule sub

The two "Fetching submodule" messages are coming from two separate calls to get_fetch_task_from_index(), and the trace does show that the code is doing "git-upload-pack" three times (one for the top level, twice for the same top/sub). We can see it by grepping for "git-upload-pack" in the resulting 'trace' file above.

Glen, as submodule.c::fetch_submodules() was created in your heavy refactoring quite recently, I thought I'd redirect this report in your direction, as I expect you'd be the most clueful in this area ;-)

Thanks.

Benedek Kozma <cyberbeni@gmail.com> writes:

Show 47 quoted lines

> Thank you for filling out a Git bug report!
> Please answer the following questions to help us understand your issue.
>
> What did you do before the bug happened? (Steps to reproduce your issue)
> Run the following command with 1 remote:
> `git fetch --all --prune --prune-tags`
> I have the following in my config that could affect this:
> ```
> [submodule]
> recurse = true
> [fetch]
> parallel = 0
> ```
>
> What did you expect to happen? (Expected behavior)
> Submodules are only fetched once.
>
> What happened instead? (Actual behavior)
> Submodules are fetched twice.
>
> What's different between what you expected and what actually happened?
> The process takes longer
>
> Anything else you want to add:
>
> Please review the rest of the bug report below.
> You can delete any lines you don't wish to share.
>
>
> [System Info]
> git version:
> git version 2.36.0
> cpu: arm64
> no commit associated with this build
> sizeof-long: 8
> sizeof-size_t: 8
> shell-path: /bin/sh
> feature: fsmonitor--daemon
> uname: Darwin 21.4.0 Darwin Kernel Version 21.4.0: Fri Mar 18 00:46:32
> PDT 2022; root:xnu-8020.101.4~15/RELEASE_ARM64_T6000 arm64
> compiler info: clang: 13.1.6 (clang-1316.0.21.2)
> libc info: no libc information available
> $SHELL (typically, interactive shell): /bin/zsh
>
>
> [Enabled Hooks]
> pre-commit