status: respect "-b" for porcelain format

There is no reason not to, as the user has to explicitly ask
for it, so we are not breaking compatibility by doing so. We
can do this simply by moving the "show_branch" flag into
the wt_status struct. As a bonus, this saves us from passing
it explicitly, simplifying the code.

Signed-off-by: Jeff King <peff@peff.net>

Documentation/git-status.txt

@@ -177,7 +177,7 @@ order is reversed (e.g 'from \-> to' becomes 'to from'). Second, a NUL
 and the terminating newline (but a space still separates the status
 field from the first filename).  Third, filenames containing special
 characters are not specially formatted; no quoting or
-backslash-escaping is performed. Fourth, there is no branch line.
+backslash-escaping is performed.
 
 CONFIGURATION
 -------------

builtin/commit.c

@@ -114,7 +114,6 @@ static enum {
 	STATUS_FORMAT_SHORT,
 	STATUS_FORMAT_PORCELAIN
 } status_format = STATUS_FORMAT_LONG;
-static int status_show_branch;
 
 static int opt_parse_m(const struct option *opt, const char *arg, int unset)
 {
@@ -459,7 +458,7 @@ static int run_status(FILE *fp, const char *index_file, const char *prefix, int
 
 	switch (status_format) {
 	case STATUS_FORMAT_SHORT:
-		wt_shortstatus_print(s, status_show_branch);
+		wt_shortstatus_print(s);
 		break;
 	case STATUS_FORMAT_PORCELAIN:
 		wt_porcelain_print(s);
@@ -1175,7 +1174,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 		OPT__VERBOSE(&verbose, "be verbose"),
 		OPT_SET_INT('s', "short", &status_format,
 			    "show status concisely", STATUS_FORMAT_SHORT),
-		OPT_BOOLEAN('b', "branch", &status_show_branch,
+		OPT_BOOLEAN('b', "branch", &s.show_branch,
 			    "show branch information"),
 		OPT_SET_INT(0, "porcelain", &status_format,
 			    "machine-readable output",
@@ -1230,7 +1229,7 @@ int cmd_status(int argc, const char **argv, const char *prefix)
 
 	switch (status_format) {
 	case STATUS_FORMAT_SHORT:
-		wt_shortstatus_print(&s, status_show_branch);
+		wt_shortstatus_print(&s);
 		break;
 	case STATUS_FORMAT_PORCELAIN:
 		wt_porcelain_print(&s);
@@ -1402,7 +1401,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		OPT_BOOLEAN(0, "dry-run", &dry_run, "show what would be committed"),
 		OPT_SET_INT(0, "short", &status_format, "show status concisely",
 			    STATUS_FORMAT_SHORT),
-		OPT_BOOLEAN(0, "branch", &status_show_branch, "show branch information"),
+		OPT_BOOLEAN(0, "branch", &s.show_branch, "show branch information"),
 		OPT_SET_INT(0, "porcelain", &status_format,
 			    "machine-readable output", STATUS_FORMAT_PORCELAIN),
 		OPT_BOOLEAN('z', "null", &s.null_termination,

t/t7508-status.sh

@@ -656,9 +656,14 @@ test_expect_success 'status --porcelain ignores color.status' '
 git config --unset color.status
 git config --unset color.ui
 
-test_expect_success 'status --porcelain ignores -b' '
+test_expect_success 'status --porcelain respects -b' '
 
 	git status --porcelain -b >output &&
+	{
+		echo "## master" &&
+		cat expect
+	} >tmp &&
+	mv tmp expect &&
 	test_cmp expect output
 
 '

wt-status.c

@@ -918,11 +918,11 @@ static void wt_shortstatus_print_tracking(struct wt_status *s)
 	fputc(s->null_termination ? '\0' : '\n', s->fp);
 }
 
-void wt_shortstatus_print(struct wt_status *s, int show_branch)
+void wt_shortstatus_print(struct wt_status *s)
 {
 	int i;
 
-	if (show_branch)
+	if (s->show_branch)
 		wt_shortstatus_print_tracking(s);
 
 	for (i = 0; i < s->change.nr; i++) {
@@ -955,5 +955,5 @@ void wt_porcelain_print(struct wt_status *s)
 	s->use_color = 0;
 	s->relative_paths = 0;
 	s->prefix = NULL;
-	wt_shortstatus_print(s, 0);
+	wt_shortstatus_print(s);
 }

wt-status.h

@@ -57,6 +57,7 @@ struct wt_status {
 	const char *ignore_submodule_arg;
 	char color_palette[WT_STATUS_MAXSLOT][COLOR_MAXLEN];
 	int null_termination;
+	int show_branch;
 
 	/* These are computed during processing of the individual sections */
 	int commitable;
@@ -73,7 +74,7 @@ void wt_status_prepare(struct wt_status *s);
 void wt_status_print(struct wt_status *s);
 void wt_status_collect(struct wt_status *s);
 
-void wt_shortstatus_print(struct wt_status *s, int show_branch);
+void wt_shortstatus_print(struct wt_status *s);
 void wt_porcelain_print(struct wt_status *s);
 
 void status_printf_ln(struct wt_status *s, const char *color, const char *fmt, ...)