Re: 'git pull --dry-run' accepted, but moves HEAD and changes working tree
On Mon, May 24, 2010 at 08:58:23AM -0500, Jeff Epler wrote:
> I don't recall why I initially typed it, I was surprised to discover
> that 'git pull --dry-run' moves HEAD and modifies the working tree.
> (I assume it's passing --dry-run to fetch, which does accept it, but
> that doesn't ensure that there's nothing at all to merge)
That is exactly what is happening.
> Maybe 'git pull --dry-run' should just be forbidden, or maybe it could
> tell the user whether the result of the pull would be a merge, FF, or no
> change.
We can't tell what would have happened, because the dry-run fetch doesn't write anything into FETCH_HEAD (which is where we would look to see what was merge-able or not). But we can at least stop at the fetch dry-run to prevent any further damage.
I have no problem with simply reporting an error, but it is easy enough to also just have it stop after doing the fetch dry-run, as below.
-- >8 --
Subject: [PATCH] pull: do nothing on --dry-run
Pull was never meant to take --dry-run at all. However, it passes unknown arguments to git-fetch, which does do a dry-run. Unfortunately, pull then attempts to merge whatever cruft was in FETCH_HEAD (which the dry-run fetch will not have written to).
Even though we never advertise --dry-run as something that should work, it is still worth being defensive because:
1. Other commands (including fetch) take --dry-run, so a
user might try it. 2. Rather than simply producing an error, it actually
changes the repository in totally unexpected ways.This patch makes "pull --dry-run" equivalent to "fetch --dry-run".
Signed-off-by: Jeff King <peff@peff.net>
---
git-pull.sh | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/git-pull.sh b/git-pull.sh
index 1a4729f..a09a44e 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -43,6 +43,7 @@ merge_args=
curr_branch=$(git symbolic-ref -q HEAD)
curr_branch_short="${curr_branch#refs/heads/}"
rebase=$(git config --bool branch.$curr_branch_short.rebase)
+dry_run=
while :
do
case "$1" in
@@ -104,6 +105,9 @@ do
--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
rebase=false
;;
+ --d|--dr|--dry|--dry-|--dry-r|--dry-ru|--dry-run)
+ dry_run=--dry-run
+ ;;
-h|--h|--he|--hel|--help)
usage
;;
@@ -216,7 +220,8 @@ test true = "$rebase" && {
done
}
orig_head=$(git rev-parse -q --verify HEAD)
-git fetch $verbosity $progress --update-head-ok "$@" || exit 1
+git fetch $verbosity $progress $dry_run --update-head-ok "$@" || exit 1
+test -z "$dry_run" || exit 0
curr_head=$(git rev-parse -q --verify HEAD)
if test -n "$orig_head" && test "$curr_head" != "$orig_head"
--
1.7.1.226.g770c5.dirty
Jeff Epler
