Re: [PATCH] sparse: ignore warning from new glibc headers

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

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Hi Danh,

On Wed, 17 Jul 2024, Đoàn Trần Công Danh wrote:

> With at least glibc 2.39, glibc provides a function declaration that
> matches with this POSIX interface:
>
>     int regexec(const regex_t *restrict preg, const char *restrict string,
>            size_t nmatch, regmatch_t pmatch[restrict], int eflags);
>
> such prototype requires variable-length-array for `pmatch'.
>
> Thus, sparse reports this error:
>
> > ../add-patch.c: note: in included file (through ../git-compat-util.h):
> > /usr/include/regex.h:682:41: error: undefined identifier '__nmatch'
> > /usr/include/regex.h:682:41: error: bad constant expression type
> > /usr/include/regex.h:682:41: error: Variable length array is used.
>
> Note: `__nmatch' is POSIX's nmatch.
>
> The glibc's intention is informing their users to provides a large
> enough buffer to hold `__nmatch' results and provides diagnosis if
> necessary.  It's merely a glibc' implementation detail.
>
> Hide that usage from sparse by using standard C11's macro:
> __STDC_NO_VLA__
>
> Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
> ---
>  Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index bc81d3395032a..4b9daca1dcc58 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1381,7 +1381,7 @@ ARFLAGS = rcs
>  PTHREAD_CFLAGS =
>
>  # For the 'sparse' target
> -SPARSE_FLAGS ?= -std=gnu99
> +SPARSE_FLAGS ?= -std=gnu99 -D__STDC_NO_VLA__
>  SP_EXTRA_FLAGS = -Wno-universal-initializer
>
>  # For informing GIT-BUILD-OPTIONS of the SANITIZE=leak,address targets
> --
> 2.45.2.599.g51c0d632d3b6f

Thank you for this patch!

Due to the brownouts today (see
https://github.com/actions/runner-images/issues/11101, surfaced e.g. in
https://github.com/git/git/actions/runs/14342895944/job/40206357016), your
patch came in handy, as it is required for the following fix:

-- snipsnap --
Subject: [PATCH] ci: upgrade `sparse` to supported build agents

The `sparse` job still uses the `ubuntu-20.04` runner pool, but that
pool is about to go away, so let's stop using it.

There is no `sparse-22.04` artifact provided by the "Build sparse for
Ubuntu" Azure Pipeline, but that is not necessary anyway because Ubuntu
22.04 has the `sparse` package: https://packages.ubuntu.com/jammy/sparse

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 .github/workflows/main.yml | 11 +----------
 ci/install-dependencies.sh |  2 +-
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ff44c0a8c067..c9455246269d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -449,20 +449,11 @@ jobs:
     if: needs.ci-config.outputs.enabled == 'yes'
     env:
       jobname: sparse
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     concurrency:
       group: sparse-${{ github.ref }}
       cancel-in-progress: ${{ needs.ci-config.outputs.skip_concurrent == 'yes' }}
     steps:
-    - name: Download a current `sparse` package
-      # Ubuntu's `sparse` version is too old for us
-      uses: git-for-windows/get-azure-pipelines-artifact@v0
-      with:
-        repository: git/git
-        definitionId: 10
-        artifact: sparse-20.04
-    - name: Install the current `sparse` package
-      run: sudo dpkg -i sparse-20.04/sparse_*.deb
     - uses: actions/checkout@v4
     - name: Install other dependencies
       run: ci/install-dependencies.sh
diff --git a/ci/install-dependencies.sh b/ci/install-dependencies.sh
index 0df74610d063..8700c0f2924d 100755
--- a/ci/install-dependencies.sh
+++ b/ci/install-dependencies.sh
@@ -119,7 +119,7 @@ StaticAnalysis)
 sparse)
 	sudo apt-get -q update -q
 	sudo apt-get -q -y install libssl-dev libcurl4-openssl-dev \
-		libexpat-dev gettext zlib1g-dev
+		libexpat-dev gettext zlib1g-dev sparse
 	;;
 Documentation)
 	sudo apt-get -q update
--
2.49.0.windows.1