Merge branch 'hn/status-compare-with-push' into jch

"git status" learned to show comparison between the current branch
and various other branches listed on status.compareBranches
configuration.

* hn/status-compare-with-push:
  status: add status.compareBranches config for multiple branch comparisons
  refactor format_branch_comparison in preparation

Documentation/config/status.adoc

@@ -17,6 +17,26 @@ status.aheadBehind::
 	`--no-ahead-behind` by default in linkgit:git-status[1] for
 	non-porcelain status formats.  Defaults to true.
 
+status.compareBranches::
+	A space-separated list of branches to compare the current branch
+	against in linkgit:git-status[1]. Each branch specification can be
+	a remote-tracking branch name (e.g. `origin/main`), or a special
+	reference like `@{upstream}` or `@{push}`. For each branch in the
+	list, git status shows whether the current branch is ahead, behind,
+	or has diverged from that branch.
++
+If not set, the default behavior is equivalent to `@{upstream}`, which
+compares against the configured upstream tracking branch.
++
+Example:
++
+----
+[status]
+	compareBranches = origin/main origin/develop
+----
++
+This would show comparisons against both `origin/main` and `origin/develop`.
+
 status.displayCommentPrefix::
 	If set to true, linkgit:git-status[1] will insert a comment
 	prefix before each output line (starting with

remote.c

@@ -29,6 +29,12 @@
 
 enum map_direction { FROM_SRC, FROM_DST };
 
+enum {
+	ENABLE_ADVICE_PULL       = (1 << 0),
+	ENABLE_ADVICE_PUSH       = (1 << 1),
+	ENABLE_ADVICE_DIVERGENCE = (1 << 2),
+};
+
 struct counted_string {
 	size_t len;
 	const char *s;
@@ -2234,43 +2240,62 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
 	return stat_branch_pair(branch->refname, base, num_ours, num_theirs, abf);
 }
 
-/*
- * Return true when there is anything to report, otherwise false.
- */
-int format_tracking_info(struct branch *branch, struct strbuf *sb,
-			 enum ahead_behind_flags abf,
-			 int show_divergence_advice)
+static char *resolve_compare_branch(struct branch *branch, const char *name)
 {
-	int ours, theirs, sti;
-	const char *full_base;
-	char *base;
-	int upstream_is_gone = 0;
+	struct strbuf buf = STRBUF_INIT;
+	const char *resolved = NULL;
+	char *ret;
 
-	sti = stat_tracking_info(branch, &ours, &theirs, &full_base, 0, abf);
-	if (sti < 0) {
-		if (!full_base)
-			return 0;
-		upstream_is_gone = 1;
+	if (!branch || !name)
+		return NULL;
+
+	if (!strcasecmp(name, "@{upstream}") || !strcasecmp(name, "@{u}"))
+		resolved = branch_get_upstream(branch, NULL);
+	else if (!strcasecmp(name, "@{push}"))
+		resolved = branch_get_push(branch, NULL);
+
+	if (resolved)
+		return xstrdup(resolved);
+
+	strbuf_addf(&buf, "refs/remotes/%s", name);
+	resolved = refs_resolve_ref_unsafe(
+		get_main_ref_store(the_repository),
+		buf.buf,
+		RESOLVE_REF_READING,
+		NULL, NULL);
+	if (resolved) {
+		ret = xstrdup(resolved);
+		strbuf_release(&buf);
+		return ret;
 	}
 
-	base = refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
-					    full_base, 0);
-	if (upstream_is_gone) {
-		strbuf_addf(sb,
-			_("Your branch is based on '%s', but the upstream is gone.\n"),
-			base);
-		if (advice_enabled(ADVICE_STATUS_HINTS))
-			strbuf_addstr(sb,
-				_("  (use \"git branch --unset-upstream\" to fixup)\n"));
-	} else if (!sti) {
+	strbuf_release(&buf);
+	return NULL;
+}
+
+static void format_branch_comparison(struct strbuf *sb,
+				     bool up_to_date,
+				     int ours, int theirs,
+				     const char *branch_name,
+				     enum ahead_behind_flags abf,
+				     unsigned flags)
+{
+	bool enable_push_advice = (flags & ENABLE_ADVICE_PUSH) &&
+		advice_enabled(ADVICE_STATUS_HINTS);
+	bool enable_pull_advice = (flags & ENABLE_ADVICE_PULL) &&
+		advice_enabled(ADVICE_STATUS_HINTS);
+	bool enable_divergence_advice = (flags & ENABLE_ADVICE_DIVERGENCE) &&
+		advice_enabled(ADVICE_STATUS_HINTS);
+
+	if (up_to_date) {
 		strbuf_addf(sb,
 			_("Your branch is up to date with '%s'.\n"),
-			base);
+			branch_name);
 	} else if (abf == AHEAD_BEHIND_QUICK) {
 		strbuf_addf(sb,
 			    _("Your branch and '%s' refer to different commits.\n"),
-			    base);
-		if (advice_enabled(ADVICE_STATUS_HINTS))
+			    branch_name);
+		if (enable_push_advice)
 			strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
 				    "git status --ahead-behind");
 	} else if (!theirs) {
@@ -2278,8 +2303,8 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb,
 			Q_("Your branch is ahead of '%s' by %d commit.\n",
 			   "Your branch is ahead of '%s' by %d commits.\n",
 			   ours),
-			base, ours);
-		if (advice_enabled(ADVICE_STATUS_HINTS))
+			branch_name, ours);
+		if (enable_push_advice)
 			strbuf_addstr(sb,
 				_("  (use \"git push\" to publish your local commits)\n"));
 	} else if (!ours) {
@@ -2289,8 +2314,8 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb,
 			   "Your branch is behind '%s' by %d commits, "
 			       "and can be fast-forwarded.\n",
 			   theirs),
-			base, theirs);
-		if (advice_enabled(ADVICE_STATUS_HINTS))
+			branch_name, theirs);
+		if (enable_pull_advice)
 			strbuf_addstr(sb,
 				_("  (use \"git pull\" to update your local branch)\n"));
 	} else {
@@ -2302,14 +2327,106 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb,
 			       "and have %d and %d different commits each, "
 			       "respectively.\n",
 			   ours + theirs),
-			base, ours, theirs);
-		if (show_divergence_advice &&
-		    advice_enabled(ADVICE_STATUS_HINTS))
+			branch_name, ours, theirs);
+		if (enable_divergence_advice)
 			strbuf_addstr(sb,
 				_("  (use \"git pull\" if you want to integrate the remote branch with yours)\n"));
 	}
-	free(base);
-	return 1;
+}
+
+/*
+ * Return true when there is anything to report, otherwise false.
+ */
+int format_tracking_info(struct branch *branch, struct strbuf *sb,
+			 enum ahead_behind_flags abf,
+			 int show_divergence_advice)
+{
+	char *compare_branches = NULL;
+	struct string_list branches = STRING_LIST_INIT_DUP;
+	struct strset processed_refs = STRSET_INIT;
+	int reported = 0;
+	size_t i;
+	const char *upstream_ref;
+	const char *push_ref;
+
+	repo_config_get_string(the_repository, "status.comparebranches",
+			       &compare_branches);
+
+	if (compare_branches) {
+		string_list_split(&branches, compare_branches, " ", -1);
+		string_list_remove_empty_items(&branches, 0);
+	} else {
+		string_list_append(&branches, "@{upstream}");
+	}
+
+	upstream_ref = branch_get_upstream(branch, NULL);
+	push_ref = branch_get_push(branch, NULL);
+
+	for (i = 0; i < branches.nr; i++) {
+		char *full_ref;
+		char *short_ref;
+		int ours, theirs, cmp;
+		int is_upstream, is_push;
+		unsigned flags = 0;
+
+		full_ref = resolve_compare_branch(branch,
+						  branches.items[i].string);
+		if (!full_ref)
+			continue;
+
+		if (!strset_add(&processed_refs, full_ref)) {
+			free(full_ref);
+			continue;
+		}
+
+		short_ref = refs_shorten_unambiguous_ref(
+			get_main_ref_store(the_repository), full_ref, 0);
+
+		is_upstream = upstream_ref && !strcmp(full_ref, upstream_ref);
+		is_push = push_ref && !strcmp(full_ref, push_ref);
+
+		if (is_upstream && (!push_ref || !strcmp(upstream_ref, push_ref)))
+			is_push = 1;
+
+		cmp = stat_branch_pair(branch->refname, full_ref,
+				       &ours, &theirs, abf);
+
+		if (cmp < 0) {
+			if (is_upstream) {
+				strbuf_addf(sb,
+					_("Your branch is based on '%s', but the upstream is gone.\n"),
+					short_ref);
+				if (advice_enabled(ADVICE_STATUS_HINTS))
+					strbuf_addstr(sb,
+						_("  (use \"git branch --unset-upstream\" to fixup)\n"));
+				reported = 1;
+			}
+			free(full_ref);
+			free(short_ref);
+			continue;
+		}
+
+		if (reported)
+			strbuf_addstr(sb, "\n");
+
+		if (is_upstream)
+			flags |= ENABLE_ADVICE_PULL;
+		if (is_push)
+			flags |= ENABLE_ADVICE_PUSH;
+		if (show_divergence_advice && is_upstream)
+			flags |= ENABLE_ADVICE_DIVERGENCE;
+		format_branch_comparison(sb, !cmp, ours, theirs, short_ref,
+					 abf, flags);
+		reported = 1;
+
+		free(full_ref);
+		free(short_ref);
+	}
+
+	string_list_clear(&branches, 0);
+	strset_clear(&processed_refs);
+	free(compare_branches);
+	return reported;
 }
 
 static int one_local_ref(const struct reference *ref, void *cb_data)

t/t6040-tracking-info.sh

@@ -292,4 +292,341 @@ test_expect_success '--set-upstream-to @{-1}' '
 	test_cmp expect actual
 '
 
+test_expect_success 'status tracking origin/main shows only main' '
+	(
+		cd test &&
+		git checkout b4 &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch b4
+	Your branch is ahead of ${SQ}origin/main${SQ} by 2 commits.
+	  (use "git push" to publish your local commits)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status --no-ahead-behind tracking origin/main shows only main' '
+	(
+		cd test &&
+		git checkout b4 &&
+		git status --no-ahead-behind >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch b4
+	Your branch and ${SQ}origin/main${SQ} refer to different commits.
+	  (use "git status --ahead-behind" for details)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'setup for compareBranches tests' '
+	(
+		cd test &&
+		git config push.default current &&
+		git config status.compareBranches "@{upstream} @{push}"
+	)
+'
+
+test_expect_success 'status.compareBranches from upstream has no duplicates' '
+	(
+		cd test &&
+		git checkout main &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch main
+	Your branch is up to date with ${SQ}origin/main${SQ}.
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches shows ahead of both upstream and push branch' '
+	(
+		cd test &&
+		git checkout -b feature2 origin/main &&
+		git push origin HEAD &&
+		advance work &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature2
+	Your branch is ahead of ${SQ}origin/main${SQ} by 1 commit.
+
+	Your branch is ahead of ${SQ}origin/feature2${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'checkout with status.compareBranches shows both branches' '
+	(
+		cd test &&
+		git checkout feature2 >../actual
+	) &&
+	cat >expect <<-EOF &&
+	Your branch is ahead of ${SQ}origin/main${SQ} by 1 commit.
+
+	Your branch is ahead of ${SQ}origin/feature2${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'setup for ahead of tracked but diverged from main' '
+	(
+		cd test &&
+		git checkout -b feature4 origin/main &&
+		advance work1 &&
+		git checkout origin/main &&
+		advance work2 &&
+		git push origin HEAD:main &&
+		git checkout feature4 &&
+		advance work3
+	)
+'
+
+test_expect_success 'status.compareBranches shows diverged and ahead' '
+	(
+		cd test &&
+		git checkout feature4 &&
+		git branch --set-upstream-to origin/main &&
+		git push origin HEAD &&
+		advance work &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature4
+	Your branch and ${SQ}origin/main${SQ} have diverged,
+	and have 3 and 1 different commits each, respectively.
+	  (use "git pull" if you want to integrate the remote branch with yours)
+
+	Your branch is ahead of ${SQ}origin/feature4${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status --no-ahead-behind with status.compareBranches' '
+	(
+		cd test &&
+		git checkout feature4 &&
+		git status --no-ahead-behind >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature4
+	Your branch and ${SQ}origin/main${SQ} refer to different commits.
+
+	Your branch and ${SQ}origin/feature4${SQ} refer to different commits.
+	  (use "git status --ahead-behind" for details)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'setup upstream remote' '
+	(
+		cd test &&
+		git remote add upstream ../. &&
+		git fetch upstream &&
+		git config remote.pushDefault origin
+	)
+'
+
+test_expect_success 'status.compareBranches with upstream and origin remotes' '
+	(
+		cd test &&
+		git checkout -b feature5 upstream/main &&
+		git push origin &&
+		advance work &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature5
+	Your branch is ahead of ${SQ}upstream/main${SQ} by 1 commit.
+
+	Your branch is ahead of ${SQ}origin/feature5${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches with upstream and origin remotes multiple compare branches' '
+	(
+		cd test &&
+		git checkout -b feature6 upstream/main &&
+		git push origin &&
+		advance work &&
+		git -c status.compareBranches="upstream/main origin/feature6 origin/feature5" status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature6
+	Your branch is ahead of ${SQ}upstream/main${SQ} by 1 commit.
+
+	Your branch is ahead of ${SQ}origin/feature6${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+
+	Your branch is ahead of ${SQ}origin/feature5${SQ} by 1 commit.
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches with diverged push branch' '
+	(
+		cd test &&
+		git checkout -b feature7 upstream/main &&
+		advance work &&
+		git push origin &&
+		git reset --hard upstream/main &&
+		advance work &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature7
+	Your branch is ahead of ${SQ}upstream/main${SQ} by 1 commit.
+
+	Your branch and ${SQ}origin/feature7${SQ} have diverged,
+	and have 1 and 1 different commits each, respectively.
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches shows up to date branches' '
+	(
+		cd test &&
+		git checkout -b feature8 upstream/main &&
+		git push origin &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature8
+	Your branch is up to date with ${SQ}upstream/main${SQ}.
+
+	Your branch is up to date with ${SQ}origin/feature8${SQ}.
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status --no-ahead-behind with status.compareBranches up to date' '
+	(
+		cd test &&
+		git checkout feature8 &&
+		git push origin &&
+		git status --no-ahead-behind >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature8
+	Your branch is up to date with ${SQ}upstream/main${SQ}.
+
+	Your branch is up to date with ${SQ}origin/feature8${SQ}.
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'checkout with status.compareBranches shows up to date' '
+	(
+		cd test &&
+		git checkout feature8 >../actual
+	) &&
+	cat >expect <<-EOF &&
+	Your branch is up to date with ${SQ}upstream/main${SQ}.
+
+	Your branch is up to date with ${SQ}origin/feature8${SQ}.
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches with upstream behind and push up to date' '
+	(
+		cd test &&
+		git checkout -b ahead upstream/main &&
+		advance work &&
+		git push upstream HEAD &&
+		git checkout -b feature9 upstream/main &&
+		git push origin &&
+		git branch --set-upstream-to upstream/ahead &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature9
+	Your branch is behind ${SQ}upstream/ahead${SQ} by 1 commit, and can be fast-forwarded.
+	  (use "git pull" to update your local branch)
+
+	Your branch is up to date with ${SQ}origin/feature9${SQ}.
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches with remapped push refspec' '
+	(
+		cd test &&
+		git checkout -b feature10 origin/main &&
+		git config remote.origin.push refs/heads/feature10:refs/heads/remapped &&
+		git push &&
+		advance work &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature10
+	Your branch is ahead of ${SQ}origin/main${SQ} by 1 commit.
+
+	Your branch is ahead of ${SQ}origin/remapped${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'status.compareBranches with remapped push and upstream remote' '
+	(
+		cd test &&
+		git checkout -b feature11 upstream/main &&
+		git config remote.origin.push refs/heads/feature11:refs/heads/remapped &&
+		git push origin &&
+		advance work &&
+		git status >../actual
+	) &&
+	cat >expect <<-EOF &&
+	On branch feature11
+	Your branch is ahead of ${SQ}upstream/main${SQ} by 1 commit.
+
+	Your branch is ahead of ${SQ}origin/remapped${SQ} by 1 commit.
+	  (use "git push" to publish your local commits)
+
+	nothing to commit, working tree clean
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'clean up after compareBranches tests' '
+	(
+		cd test &&
+		git config --unset status.compareBranches
+	)
+'
+
 test_done