There is currently no easy way to take the diff between the working tree
or index and the merge base between an arbitrary commit and HEAD. Even
diff's `...` notation doesn't allow this because it only works between
commits. However, the ability to do this would be desirable to a user
who would like to see all the changes they've made on a branch plus
uncommitted changes without taking into account changes made in the
upstream branch.
Teach diff-index and diff (with one commit) the --merge-base option
which allows a user to use the merge base of a commit and HEAD as the
"before" side.
Signed-off-by: Denton Liu <liu.denton@xxxxxxxxx>
---
Documentation/git-diff-index.txt | 7 +++-
Documentation/git-diff.txt | 12 ++++--
builtin/diff-index.c | 2 +
builtin/diff.c | 2 +
diff-lib.c | 13 +++++-
diff.h | 1 +
t/t4068-diff-symmetric-merge-base.sh | 59 ++++++++++++++++++++++++++++
7 files changed, 90 insertions(+), 6 deletions(-)
diff --git a/Documentation/git-diff-index.txt b/Documentation/git-diff-index.txt
index 25fe165f00..27acb31cbf 100644
--- a/Documentation/git-diff-index.txt
+++ b/Documentation/git-diff-index.txt
@@ -9,7 +9,7 @@ git-diff-index - Compare a tree to the working tree or index
SYNOPSIS
--------
[verse]
-'git diff-index' [-m] [--cached] [<common diff options>] <tree-ish> [<path>...]
+'git diff-index' [-m] [--cached] [--merge-base] [<common diff options>] <tree-ish> [<path>...]
DESCRIPTION
-----------
@@ -29,6 +29,11 @@ include::diff-options.txt[]
--cached::
Do not consider the on-disk file at all.
+--merge-base::
+ Instead of comparing <tree-ish> directly, use the merge base
+ between <tree-ish> and HEAD instead. <tree-ish> must be a
+ commit.
+
-m::
By default, files recorded in the index but not checked
out are reported as deleted. This flag makes
diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index 8f7b4ed3ca..762ee6d074 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -10,7 +10,7 @@ SYNOPSIS
--------
[verse]
'git diff' [<options>] [<commit>] [--] [<path>...]
-'git diff' [<options>] --cached [<commit>] [--] [<path>...]
+'git diff' [<options>] --cached [--merge-base] [<commit>] [--] [<path>...]
'git diff' [<options>] <commit> [<commit>...] <commit> [--] [<path>...]
'git diff' [<options>] <commit>...<commit> [--] [<path>...]
'git diff' [<options>] <blob> <blob>
@@ -40,7 +40,7 @@ files on disk.
or when running the command outside a working tree
controlled by Git. This form implies `--exit-code`.
-'git diff' [<options>] --cached [<commit>] [--] [<path>...]::
+'git diff' [<options>] --cached [--merge-base] [<commit>] [--] [<path>...]::
This form is to view the changes you staged for the next
commit relative to the named <commit>. Typically you
@@ -49,6 +49,10 @@ files on disk.
If HEAD does not exist (e.g. unborn branches) and
<commit> is not given, it shows all staged changes.
--staged is a synonym of --cached.
++
+If --merge-base is given, instead of using <commit>, use the merge base
+of <commit> and HEAD. `git diff --merge-base A` is equivalent to
+`git diff $(git merge-base A HEAD)`.
'git diff' [<options>] <commit> [--] [<path>...]::
@@ -89,8 +93,8 @@ files on disk.
Just in case you are doing something exotic, it should be
noted that all of the <commit> in the above description, except
-in the last two forms that use `..` notations, can be any
-<tree>.
+in the `--merge-base` case and in the last two forms that use `..`
+notations, can be any <tree>.
For a more complete list of ways to spell <commit>, see
"SPECIFYING REVISIONS" section in linkgit:gitrevisions[7].
diff --git a/builtin/diff-index.c b/builtin/diff-index.c
index c3878f7ad6..7f5281c461 100644
--- a/builtin/diff-index.c
+++ b/builtin/diff-index.c
@@ -33,6 +33,8 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
if (!strcmp(arg, "--cached"))
option |= DIFF_INDEX_CACHED;
+ else if (!strcmp(arg, "--merge-base"))
+ option |= DIFF_INDEX_MERGE_BASE;
else
usage(diff_cache_usage);
}
diff --git a/builtin/diff.c b/builtin/diff.c
index e45e19e37e..1baea18ae0 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -139,6 +139,8 @@ static int builtin_diff_index(struct rev_info *revs,
const char *arg = argv[1];
if (!strcmp(arg, "--cached") || !strcmp(arg, "--staged"))
option |= DIFF_INDEX_CACHED;
+ else if (!strcmp(arg, "--merge-base"))
+ option |= DIFF_INDEX_MERGE_BASE;
else
usage(builtin_diff_usage);
argv++; argc--;
diff --git a/diff-lib.c b/diff-lib.c
index e01c3f0612..68bf86f289 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -569,13 +569,24 @@ void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb)
int run_diff_index(struct rev_info *revs, unsigned int option)
{
struct object_array_entry *ent;
+ struct object_id oid;
+ const char *name;
if (revs->pending.nr != 1)
BUG("run_diff_index must be passed exactly one tree");
trace_performance_enter();
ent = revs->pending.objects;
- if (diff_cache(revs, &ent->item->oid, ent->name, !!(option & DIFF_INDEX_CACHED)))
+
+ if (option & DIFF_INDEX_MERGE_BASE) {
+ diff_get_merge_base(revs, &oid);
+ name = xstrdup(oid_to_hex(&oid));
+ } else {
+ oidcpy(&oid, &ent->item->oid);
+ name = ent->name;
+ }
+
+ if (diff_cache(revs, &oid, name, !!(option & DIFF_INDEX_CACHED)))
exit(128);
diff_set_mnemonic_prefix(&revs->diffopt, "c/", (option & DIFF_INDEX_CACHED) ? "i/" : "w/");
diff --git a/diff.h b/diff.h
index ae2bb7001a..0485786b68 100644
--- a/diff.h
+++ b/diff.h
@@ -588,6 +588,7 @@ void diff_get_merge_base(const struct rev_info *revs, struct object_id *mb);
#define DIFF_RACY_IS_MODIFIED 02
int run_diff_files(struct rev_info *revs, unsigned int option);
#define DIFF_INDEX_CACHED 01
+#define DIFF_INDEX_MERGE_BASE 02
int run_diff_index(struct rev_info *revs, unsigned int option);
int do_diff_cache(const struct object_id *, struct diff_options *);
diff --git a/t/t4068-diff-symmetric-merge-base.sh b/t/t4068-diff-symmetric-merge-base.sh
index bd4cf254d9..49432379cb 100755
--- a/t/t4068-diff-symmetric-merge-base.sh
+++ b/t/t4068-diff-symmetric-merge-base.sh
@@ -97,4 +97,63 @@ test_expect_success 'diff --merge-base with three commits' '
test_i18ngrep "usage" err
'
+for cmd in diff-index diff
+do
+ test_expect_success "$cmd --merge-base with one commit" '
+ git checkout master &&
+ git $cmd commit-C >expect &&
+ git $cmd --merge-base br2 >actual &&
+ test_cmp expect actual
+ '
+
+ test_expect_success "$cmd --merge-base with one commit and unstaged changes" '
+ git checkout master &&
+ test_when_finished git reset --hard &&
+ echo unstaged >>c &&
+ git $cmd commit-C >expect &&
+ git $cmd --merge-base br2 >actual &&
+ test_cmp expect actual
+ '
+
+ test_expect_success "$cmd --merge-base with one commit and staged and unstaged changes" '
+ git checkout master &&
+ test_when_finished git reset --hard &&
+ echo staged >>c &&
+ git add c &&
+ echo unstaged >>c &&
+ git $cmd commit-C >expect &&
+ git $cmd --merge-base br2 >actual &&
+ test_cmp expect actual
+ '
+
+ test_expect_success "$cmd --merge-base --cached with one commit and staged and unstaged changes" '
+ git checkout master &&
+ test_when_finished git reset --hard &&
+ echo staged >>c &&
+ git add c &&
+ echo unstaged >>c &&
+ git $cmd --cached commit-C >expect &&
+ git $cmd --cached --merge-base br2 >actual &&
+ test_cmp expect actual
+ '
+
+ test_expect_success "$cmd --merge-base with non-commit" '
+ git checkout master &&
+ test_must_fail git $cmd --merge-base master^{tree} 2>err &&
+ test_i18ngrep "fatal: --merge-base only works with commits" err
+ '
+
+ test_expect_success "$cmd --merge-base with no merge bases and one commit" '
+ git checkout master &&
+ test_must_fail git $cmd --merge-base br3 2>err &&
+ test_i18ngrep "fatal: no merge base found" err
+ '
+
+ test_expect_success "$cmd --merge-base with multiple merge bases and one commit" '
+ git checkout master &&
+ test_must_fail git $cmd --merge-base br1 2>err &&
+ test_i18ngrep "fatal: multiple merge bases found" err
+ '
+done
+
test_done
--
2.28.0.618.gf4bc123cb7
