Subject: Re: [PATCH 2/7] diff.c: take "prefix" argument in diff_opt_parse()

From: Duy Nguyen <[email-masked]>
Date: Thu, 21 Jan 2016 18:48:44 +0700

On Wed, Jan 20, 2016 at 01:49:21PM -0800, Junio C Hamano wrote:
> Jeff King <[email-masked]> writes:
> 
> > On Wed, Jan 20, 2016 at 12:23:38PM -0800, Junio C Hamano wrote:
> >
> >> Nguyễn Thái Ngọc Duy  <[email-masked]> writes:
> >> 
> >> > This will be important later when diff_opt_parse() accepts paths as
> >> > arguments. Paths must be prefixed before access because setup code
> >> > moves cwd but does not (and cannot) update command line options.
> >> 
> >> The above sounds like a sensible thing to do (note: I didn't read
> >> the patch or remainder of the series), but makes me wonder how the
> >> existing --orderfile option works without this support.  Perhaps it
> >> is not working and needs to be updated to take advantage of this
> >> change, too?
> >
> > Yeah, I think it simply does not work.
> >
> >   $ >main-order
> >   $ mkdir subdir && >subdir/sub-order
> >   $ cd subdir
> >   $ git show -Osub-order
> >   fatal: failed to read orderfile 'sub-order': No such file or directory
> >   $ git show -Omain-order
> >   [shows diff]
> 
> Good.
> 
> Then 2/7 can be rerolled and advertised as "make -O to work from
> subdirectories", and can gradulate regardless of the remainder of
> the series.  Even if the rest needs rerolls to get it right (or
> takes until 2019 to mature ;-), we will have one less change to
> re-review in the process as we can push these early and obviously
> correct part out separately.
> 

I didn't know there was already an option that takes a path. I read
through the function and found another one. So here's the standalone
patch that fixes both.

-- 8< --
Subject: [PATCH] diff: make -O and --output work in subdirectory

Signed-off-by: Nguyễn Thái Ngọc Duy <[email-masked]>
---
 builtin/am.c          |  2 +-
 diff-no-index.c       |  3 ++-
 diff.c                | 14 ++++++++++----
 diff.h                |  2 +-
 revision.c            |  2 +-
 t/t4056-diff-order.sh |  6 ++++++
 6 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/builtin/am.c b/builtin/am.c
index 9fb42fd..f009b6c 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -1657,7 +1657,7 @@ static int fall_back_threeway(const struct am_state *state, const char *index_pa
 
 		init_revisions(&rev_info, NULL);
 		rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
-		diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1);
+		diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
 		add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
 		diff_setup_done(&rev_info.diffopt);
 		run_diff_index(&rev_info, 1);
diff --git a/diff-no-index.c b/diff-no-index.c
index 8e0fd27..aa81a15 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -252,7 +252,8 @@ void diff_no_index(struct rev_info *revs,
 		else if (!strcmp(argv[i], "--"))
 			i++;
 		else {
-			j = diff_opt_parse(&revs->diffopt, argv + i, argc - i);
+			j = diff_opt_parse(&revs->diffopt, argv + i, argc - i,
+					   revs->prefix);
 			if (j <= 0)
 				die("invalid diff option/value: %s", argv[i]);
 			i += j;
diff --git a/diff.c b/diff.c
index 80eb0c2..2136b69 100644
--- a/diff.c
+++ b/diff.c
@@ -3693,12 +3693,16 @@ static int parse_ws_error_highlight(struct diff_options *opt, const char *arg)
 	return 1;
 }
 
-int diff_opt_parse(struct diff_options *options, const char **av, int ac)
+int diff_opt_parse(struct diff_options *options,
+		   const char **av, int ac, const char *prefix)
 {
 	const char *arg = av[0];
 	const char *optarg;
 	int argcount;
 
+	if (!prefix)
+		prefix = "";
+
 	/* Output format options */
 	if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
 	    || opt_arg(arg, 'U', "unified", &options->context))
@@ -3915,7 +3919,8 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	else if (!strcmp(arg, "--pickaxe-regex"))
 		options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
 	else if ((argcount = short_opt('O', av, &optarg))) {
-		options->orderfile = optarg;
+		const char *path = prefix_filename(prefix, strlen(prefix), optarg);
+		options->orderfile = xstrdup(path);
 		return argcount;
 	}
 	else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
@@ -3954,9 +3959,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 	else if (!strcmp(arg, "--no-function-context"))
 		DIFF_OPT_CLR(options, FUNCCONTEXT);
 	else if ((argcount = parse_long_opt("output", av, &optarg))) {
-		options->file = fopen(optarg, "w");
+		const char *path = prefix_filename(prefix, strlen(prefix), optarg);
+		options->file = fopen(path, "w");
 		if (!options->file)
-			die_errno("Could not open '%s'", optarg);
+			die_errno("Could not open '%s'", path);
 		options->close_file = 1;
 		return argcount;
 	} else
diff --git a/diff.h b/diff.h
index 893f446..4537e38 100644
--- a/diff.h
+++ b/diff.h
@@ -268,7 +268,7 @@ extern int parse_long_opt(const char *opt, const char **argv,
 extern int git_diff_basic_config(const char *var, const char *value, void *cb);
 extern int git_diff_ui_config(const char *var, const char *value, void *cb);
 extern void diff_setup(struct diff_options *);
-extern int diff_opt_parse(struct diff_options *, const char **, int);
+extern int diff_opt_parse(struct diff_options *, const char **, int, const char *);
 extern void diff_setup_done(struct diff_options *);
 
 #define DIFF_DETECT_RENAME	1
diff --git a/revision.c b/revision.c
index 0a282f5..14daefb 100644
--- a/revision.c
+++ b/revision.c
@@ -2049,7 +2049,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	} else if (!strcmp(arg, "--ignore-missing")) {
 		revs->ignore_missing = 1;
 	} else {
-		int opts = diff_opt_parse(&revs->diffopt, argv, argc);
+		int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
 		if (!opts)
 			unkv[(*unkc)++] = arg;
 		return opts;
diff --git a/t/t4056-diff-order.sh b/t/t4056-diff-order.sh
index c0460bb..43dd474 100755
--- a/t/t4056-diff-order.sh
+++ b/t/t4056-diff-order.sh
@@ -68,6 +68,12 @@ test_expect_success POSIXPERM,SANITY 'unreadable orderfile' '
 	test_must_fail git diff -Ounreadable_file --name-only HEAD^..HEAD
 '
 
+test_expect_success "orderfile using option from subdir with --output" '
+	mkdir subdir &&
+	git -C subdir diff -O../order_file_1 --output ../actual --name-only HEAD^..HEAD &&
+	test_cmp expect_1 actual
+'
+
 for i in 1 2
 do
 	test_expect_success "orderfile using option ($i)" '
-- 
2.7.0.125.g9eec362

-- 8< --