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

"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: clarify how status.compareBranches deduplicates
  status: add status.compareBranches config for multiple branch comparisons
  refactor format_branch_comparison in preparation

Author: gitster

Documentation/config/status.adoc

@@ -17,6 +17,31 @@ 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 branch comparison specifiers to use in
+	linkgit:git-status[1]. Currently, only `@{upstream}` and `@{push}`
+	are supported. They are interpreted as `branch@{upstream}` and
+	`branch@{push}` for the current branch.
++
+If not set, the default behavior is equivalent to `@{upstream}`, which
+compares against the configured upstream tracking branch.
++
+The entries are shown in the order they appear in the configuration.
+Duplicate entries that resolve to the same ref are suppressed after
+their first occurrence, so `@{push} @{upstream} @{push}` shows at
+most two comparisons.  When `@{upstream}` and `@{push}` resolve to
+the same remote-tracking branch, only one comparison is shown.
++
+Example:
++
+----
+[status]
+	compareBranches = @{upstream} @{push}
+----
++
+This would show comparisons against both the configured upstream and push
+tracking branches for the current branch.
+
 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;
@@ -2234,52 +2240,58 @@ 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;
+	const char *resolved = NULL;
 
-	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}")) {
+		resolved = branch_get_upstream(branch, NULL);
+	} else if (!strcasecmp(name, "@{push}")) {
+		resolved = branch_get_push(branch, NULL);
+	} else {
+		warning(_("ignoring value '%s' for status.compareBranches, "
+			  "only @{upstream} and @{push} are supported"),
+			name);
+		return NULL;
 	}
 
-	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) {
+	if (resolved)
+		return xstrdup(resolved);
+	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 use_push_advice = (flags & ENABLE_ADVICE_PUSH);
+	bool use_pull_advice = (flags & ENABLE_ADVICE_PULL);
+	bool use_divergence_advice = (flags & ENABLE_ADVICE_DIVERGENCE);
+
+	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 (use_push_advice && advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
 				    "git status --ahead-behind");
 	} else if (!theirs) {
 		strbuf_addf(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 (use_push_advice && advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addstr(sb,
 				_("  (use \"git push\" to publish your local commits)\n"));
 	} else if (!ours) {
@@ -2289,8 +2301,8 @@ 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 (use_pull_advice && advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addstr(sb,
 				_("  (use \"git pull\" to update your local branch)\n"));
 	} else {
@@ -2302,14 +2314,106 @@ 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 (use_divergence_advice && advice_enabled(ADVICE_STATUS_HINTS))
 			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)