Merge branch 'jk/am-retry'

"git am" has a safety feature to prevent it from starting a new
session when there already is a session going.  It reliably
triggers when a mbox is given on the command line, but it has to
rely on the tty-ness of the standard input.  Add an explicit way to
opt out of this safety with a command line option.

* jk/am-retry:
  test-terminal: drop stdin handling
  am: add explicit "--retry" option

Documentation/git-am.txt

@@ -18,7 +18,7 @@ SYNOPSIS
 	 [--quoted-cr=<action>]
 	 [--empty=(stop|drop|keep)]
 	 [(<mbox> | <Maildir>)...]
-'git am' (--continue | --skip | --abort | --quit | --show-current-patch[=(diff|raw)] | --allow-empty)
+'git am' (--continue | --skip | --abort | --quit | --retry | --show-current-patch[=(diff|raw)] | --allow-empty)
 
 DESCRIPTION
 -----------
@@ -208,6 +208,12 @@ Valid <action> for the `--whitespace` option are:
 	Abort the patching operation but keep HEAD and the index
 	untouched.
 
+--retry::
+	Try to apply the last conflicting patch again. This is generally
+	only useful for passing extra options to the retry attempt
+	(e.g., `--3way`), since otherwise you'll just see the same
+	failure again.
+
 --show-current-patch[=(diff|raw)]::
 	Show the message at which `git am` has stopped due to
 	conflicts.  If `raw` is specified, show the raw contents of

builtin/am.c

@@ -2393,6 +2393,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		  N_("show the patch being applied"),
 		  PARSE_OPT_CMDMODE | PARSE_OPT_OPTARG | PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP,
 		  parse_opt_show_current_patch, RESUME_SHOW_PATCH_RAW },
+		OPT_CMDMODE(0, "retry", &resume_mode,
+			N_("try to apply current patch again"),
+			RESUME_APPLY),
 		OPT_CMDMODE(0, "allow-empty", &resume_mode,
 			N_("record the empty patch as an empty commit"),
 			RESUME_ALLOW_EMPTY),

t/t4153-am-resume-override-opts.sh

@@ -3,7 +3,6 @@
 test_description='git-am command-line options override saved options'
 
 . ./test-lib.sh
-. "$TEST_DIRECTORY"/lib-terminal.sh
 
 format_patch () {
 	git format-patch --stdout -1 "$1" >"$1".eml
@@ -27,7 +26,12 @@ test_expect_success 'setup' '
 	format_patch side2
 '
 
-test_expect_success TTY '--3way overrides --no-3way' '
+test_expect_success '--retry fails without in-progress operation' '
+	test_must_fail git am --retry 2>err &&
+	test_grep "operation not in progress" err
+'
+
+test_expect_success '--3way overrides --no-3way' '
 	rm -fr .git/rebase-apply &&
 	git reset --hard &&
 	git checkout renamed-file &&
@@ -40,7 +44,7 @@ test_expect_success TTY '--3way overrides --no-3way' '
 
 	# Applying side1 with am --3way will succeed due to the threeway-merge.
 	# Applying side2 will fail as --3way does not apply to it.
-	test_must_fail test_terminal git am --3way </dev/zero &&
+	test_must_fail git am --retry --3way &&
 	test_path_is_dir .git/rebase-apply &&
 	test side1 = "$(cat file2)"
 '
@@ -84,7 +88,7 @@ test_expect_success '--signoff overrides --no-signoff' '
 	test $(git cat-file commit HEAD | grep -c "Signed-off-by:") -eq 0
 '
 
-test_expect_success TTY '--reject overrides --no-reject' '
+test_expect_success '--reject overrides --no-reject' '
 	rm -fr .git/rebase-apply &&
 	git reset --hard &&
 	git checkout first &&
@@ -94,7 +98,7 @@ test_expect_success TTY '--reject overrides --no-reject' '
 	test_path_is_dir .git/rebase-apply &&
 	test_path_is_missing file.rej &&
 
-	test_must_fail test_terminal git am --reject </dev/zero &&
+	test_must_fail git am --retry --reject </dev/zero &&
 	test_path_is_dir .git/rebase-apply &&
 	test_path_is_file file.rej
 '

t/test-terminal.perl

@@ -5,17 +5,15 @@ use warnings;
 use IO::Pty;
 use File::Copy;
 
-# Run @$argv in the background with stdio redirected to $in, $out and $err.
+# Run @$argv in the background with stdio redirected to $out and $err.
 sub start_child {
-	my ($argv, $in, $out, $err) = @_;
+	my ($argv, $out, $err) = @_;
 	my $pid = fork;
 	if (not defined $pid) {
 		die "fork failed: $!"
 	} elsif ($pid == 0) {
-		open STDIN, "<&", $in;
 		open STDOUT, ">&", $out;
 		open STDERR, ">&", $err;
-		close $in;
 		close $out;
 		exec(@$argv) or die "cannot exec '$argv->[0]': $!"
 	}
@@ -51,17 +49,6 @@ sub xsendfile {
 	copy($in, $out, 4096) or $!{EIO} or die "cannot copy from child: $!";
 }
 
-sub copy_stdin {
-	my ($in) = @_;
-	my $pid = fork;
-	if (!$pid) {
-		xsendfile($in, \*STDIN);
-		exit 0;
-	}
-	close($in);
-	return $pid;
-}
-
 sub copy_stdio {
 	my ($out, $err) = @_;
 	my $pid = fork;
@@ -81,25 +68,15 @@ if ($#ARGV < 1) {
 	die "usage: test-terminal program args";
 }
 $ENV{TERM} = 'vt100';
-my $parent_in = new IO::Pty;
 my $parent_out = new IO::Pty;
 my $parent_err = new IO::Pty;
-$parent_in->set_raw();
 $parent_out->set_raw();
 $parent_err->set_raw();
-$parent_in->slave->set_raw();
 $parent_out->slave->set_raw();
 $parent_err->slave->set_raw();
-my $pid = start_child(\@ARGV, $parent_in->slave, $parent_out->slave, $parent_err->slave);
-close $parent_in->slave;
+my $pid = start_child(\@ARGV, $parent_out->slave, $parent_err->slave);
 close $parent_out->slave;
 close $parent_err->slave;
-my $in_pid = copy_stdin($parent_in);
 copy_stdio($parent_out, $parent_err);
 my $ret = finish_child($pid);
-# If the child process terminates before our copy_stdin() process is able to
-# write all of its data to $parent_in, the copy_stdin() process could stall.
-# Send SIGTERM to it to ensure it terminates.
-kill 'TERM', $in_pid;
-finish_child($in_pid);
 exit($ret);