Salikh ZakirovBefore this change, .git/HEAD file played two roles: (a) point to the base commit of the working directory (b) point to current branch
This combination leads to the confusing user experience if the branch changes independently of the working directory. This can happen in following cases:
1) git clone repo repo2 cd repo2 ... edit something git commit -a git push
2) checking out the same branch in the another working directory associated with the same repository, e.g. created by contrib/workdir/git-new-workdir
git new-workdir repo repo2 cd repo2 ... edit something git commit -a
In both cases original repository will report differences between index and HEAD, even if though particular working directory state has not been changed at all.
This patch separates the notion of the current branch from the base commit. HEAD will always be "detached", and will store the hash of the base commit. Newly introduced BRANCH reference will point to the current branch.
When new commit is created, it is first stored in the HEAD. Then HEAD is compared to the branch head (BRANCH), and branch head is updated only if it is fast forward. So, in all simple case there will be no difference in the workflow.
In the "irregular" use cases above, branch head may diverge from the base commit of the repository. This situation is detected by the updaters of the HEAD, and user is advised to run merge. ---
Unfortunately, I have not figured out how to set up an empty repository to use separate HEAD and BRANCH, so one needs to set up an existing repository manually in order to play with this change:
git rev-parse HEAD > .git/HEAD.new mv .git/HEAD .git/BRANCH mv .git/HEAD.new .git/HEAD
The way branch head is updated after HEAD update in this patch is clearly unacceptable, as it causes too much code duplication. I wonder if it would be better to introduce a special case in git-update-ref?
git-checkout.sh | 4 +++- git-commit.sh | 16 ++++++++++++++++ git-merge.sh | 15 +++++++++++++++ wt-status.c | 11 +++++++---- wt-status.h | 1 + 5 files changed, 42 insertions(+), 5 deletions(-)
diff --git a/git-checkout.sh b/git-checkout.sh index f6d58ac..8e1a1ab 100755 --- a/git-checkout.sh +++ b/git-checkout.sh @@ -266,7 +266,9 @@ if [ "$?" -eq 0 ]; then if test -n "$branch" then old_branch_name=`expr "z$oldbranch" : 'zrefs/heads/\(.*\)'` - GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "refs/heads/$branch" + GIT_DIR="$GIT_DIR" git symbolic-ref -m "checkout: moving from ${old_branch_name:-$old} to $branch" BRANCH "refs/heads/$branch" + commit=$(git rev-parse --verify BRANCH 2>/dev/null) && + git update-ref --no-deref -m "checkout: moving from ${old_branch_name:-$old} to $branch" HEAD "$commit" if test -n "$quiet" then true # nothing diff --git a/git-commit.sh b/git-commit.sh index 2c4a406..b7315c1 100755 --- a/git-commit.sh +++ b/git-commit.sh @@ -609,7 +609,23 @@ then mv "$NEXT_INDEX" "$THIS_INDEX" else : ;# happy + fi && { + branchhead=$(git rev-parse --verify BRANCH 2>/dev/null) + if test -n "$branchhead" + then + if test -z "`git rev-list $commit..$branchhead`" + then + # fast-forward, update the branch pointer as well + git update-ref -m "$GIT_REFLOG_ACTION: $rlogm" BRANCH $commit "$branchhead" + else + name=$(git symbolic-ref BRANCH | sed 's,refs/heads/,,') + echo >&2 "* HEAD diverged from $name" + echo >&2 "* Consider 'git merge $name'" + fi + else + git-update-ref -m "$GIT_REFLOG_ACTION: $rlogm" BRANCH $commit "$branchhead" fi + } else echo >&2 "* no commit message? aborting commit." false diff --git a/git-merge.sh b/git-merge.sh index 1c123a3..3d4b31b 100755 --- a/git-merge.sh +++ b/git-merge.sh @@ -94,6 +94,21 @@ finish () { *) git update-ref -m "$rlogm" HEAD "$1" "$head" || exit 1 git gc --auto + branchhead=$(git rev-parse --verify BRANCH 2>/dev/null) + if test -n "$branchhead" + then + if test -z "`git rev-list $commit..$branchhead`" + then + # fast-forward, update the branch pointer as well + git update-ref -m "$rlogm" BRANCH "$1" "$branchhead" || exit 1 + else + name=$(git symbolic-ref BRANCH | sed 's,refs/heads/,,') + echo >&2 "* HEAD diverged from $name" + echo >&2 "* Consider 'git merge $name'" + fi + else + git-update-ref -m "$GIT_REFLOG_ACTION: $rlogm" BRANCH $commit "$branchhead" + fi ;; esac ;; diff --git a/wt-status.c b/wt-status.c index bf2fe8d..9fe5d10 100644 --- a/wt-status.c +++ b/wt-status.c @@ -44,12 +44,14 @@ static const char* color(int slot) void wt_status_prepare(struct wt_status *s) { - unsigned char sha1[20]; - const char *head; + unsigned char sha1[20], sha2[20]; + const char *head, *branch; memset(s, 0, sizeof(*s)); head = resolve_ref("HEAD", sha1, 0, NULL); - s->branch = head ? xstrdup(head) : NULL; + branch = resolve_ref("BRANCH", sha2, 0, NULL); + s->diverged = hashcmp(sha1, sha2); + s->branch = branch ? xstrdup(branch) : NULL; s->reference = "HEAD"; s->fp = stdout; s->index_file = get_index_file(); @@ -309,6 +311,7 @@ void wt_status_print(struct wt_status *s) if (s->branch) { const char *on_what = "On branch "; const char *branch_name = s->branch; + const char *diverged = (s->diverged ? ", diverged" : ""); if (!prefixcmp(branch_name, "refs/heads/")) branch_name += 11; else if (!strcmp(branch_name, "HEAD")) { @@ -316,7 +319,7 @@ void wt_status_print(struct wt_status *s) on_what = "Not currently on any branch."; } color_fprintf_ln(s->fp, color(WT_STATUS_HEADER), - "# %s%s", on_what, branch_name); + "# %s%s%s", on_what, branch_name, diverged); } if (s->is_initial) { diff --git a/wt-status.h b/wt-status.h index 7744932..db8129d 100644 --- a/wt-status.h +++ b/wt-status.h @@ -17,6 +17,7 @@ struct wt_status { int verbose; int amend; int untracked; + int diverged; /* These are computed during processing of the individual sections */ int commitable; int workdir_dirty;
-- 1.5.3.5.610.g3532b
