Re: [PATCH v3] scripts/setlocalversion: Improve -dirty check with git-status --no-optional-locks

Masahiro Yamada
2018-11-19T14:43:10Z

On Thu, Nov 15, 2018 at 11:12 AM Brian Norris <briannorris@chromium.org> wrote:
>
> git-diff-index does not refresh the index for you, so using it for a
> "-dirty" check can give misleading results. Commit 6147b1cf19651
> ("scripts/setlocalversion: git: Make -dirty check more robust") tried to
> fix this by switching to git-status, but it overlooked the fact that
> git-status also writes to the .git directory of the source tree, which
> is definitely not kosher for an out-of-tree (O=) build. That is getting
> reverted.
>
> Fortunately, git-status now supports avoiding writing to the index via
> the --no-optional-locks flag, as of git 2.14. It still calculates an
> up-to-date index, but it avoids writing it out to the .git directory.
>
> So, let's retry the solution from commit 6147b1cf19651 using this new
> flag first, and if it fails, we assume this is an older version of git
> and just use the old git-diff-index method.
>
> It's hairy to get the 'grep -vq' (inverted matching) correct by stashing
> the output of git-status (you have to be careful about the difference
> betwen "empty stdin" and "blank line on stdin"), so just pipe the output
> directly to grep and use a regex that's good enough for both the
> git-status and git-diff-index version.
>
> Cc: Genki Sky <sky@genki.is>
> Cc: Christian Kujau <lists@nerdbynature.de>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Suggested-by: Alexander Kapshuk <alexander.kapshuk@gmail.com>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
> v1 -> v2:
> * handle empty (non-dirty) results properly, where
> echo "${empty_variable}" | grep -qv "${something_else}"
> always has a 0 exit status (a blank line is an inverted match for any
> non-blank expression). Just pipe directly to grep instead, with a
> hopefully-not-too-permissive regex to handle both versions.
> * actually tested with dirty and non-dirty trees this time
>
> v2 -> v3:
> * switch to extended regex (-E), instead of relying on GNU extension
> (\?)
> ---

Applied to linux-kbuild.
Thanks!

> scripts/setlocalversion | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/setlocalversion b/scripts/setlocalversion
> index 71f39410691b..365b3c2b8f43 100755
> --- a/scripts/setlocalversion
> +++ b/scripts/setlocalversion
> @@ -73,8 +73,16 @@ scm_version()
> printf -- '-svn%s' "`git svn find-rev $head`"
> fi
>
> - # Check for uncommitted changes
> - if git diff-index --name-only HEAD | grep -qv "^scripts/package"; then
> + # Check for uncommitted changes.
> + # First, with git-status, but --no-optional-locks is only
> + # supported in git >= 2.14, so fall back to git-diff-index if
> + # it fails. Note that git-diff-index does not refresh the
> + # index, so it may give misleading results. See
> + # git-update-index(1), git-diff-index(1), and git-status(1).
> + if {
> + git --no-optional-locks status -uno --porcelain 2>/dev/null ||
> + git diff-index --name-only HEAD
> + } | grep -qvE '^(.. )?scripts/package'; then
> printf '%s' -dirty
> fi
>
> --
> 2.19.1.930.g4563a0d9d0-goog

--
Best Regards
Masahiro Yamada