Re: [PATCH 3/5] commit-graph: use parse_options_concat()

On Mon, Feb 15 2021, Taylor Blau wrote:

On Mon, Feb 15, 2021 at 07:41:16PM +0100, Ævar Arnfjörð Bjarmason wrote:

quoted

Make use of the parse_options_concat() so we don't need to copy/paste
common options like --object-dir. This is inspired by a similar change
to "checkout" in 2087182272
(checkout: split options[] array in three pieces, 2019-03-29).

A minor behavior change here is that now we're going to list both
--object-dir and --progress first, before we'd list --progress along
with other options.

"Behavior change" referring only to the output of `git commit-graph -h`,
no?

Looking at the code (and understanding this whole situation a little bit
better), I'd think that this wouldn't cause us to parse anything
differently before or after this change, right?

Indeed, I just mean the "-h" or "--invalid-opt" output changed in the
order we show the options in.

quoted

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 builtin/commit-graph.c | 43 ++++++++++++++++++++++++------------------
 1 file changed, 25 insertions(+), 18 deletions(-)

diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index baead04a03..a7718b2025 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c

@@ -44,6 +44,21 @@ static struct opts_commit_graph {
 	int enable_changed_paths;
 } opts;

+static struct option *add_common_options(struct option *prevopts)
+{
+	struct option options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			   N_("dir"),
+			   N_("the object directory to store the graph")),
+		OPT_BOOL(0, "progress", &opts.progress,
+			 N_("force progress reporting")),
+		OPT_END()
+	};

I'm nitpicking, but I wouldn't be sad to see this called "common"
instead".

Can't this also be declared statically?

It happens to work now to do that, but try it in builtin/checkout.c and
you'll see it blows up with a wall of "initializer element is not
constant".

Probably better to be consistent in parse_options() usage than make it
safe for that sort of use...

quoted

+	struct option *newopts = parse_options_concat(options, prevopts);
+	free(prevopts);
+	return newopts;
+}
+
 static struct object_directory *find_odb(struct repository *r,
 					 const char *obj_dir)
 {

@@ -75,22 +90,20 @@ static int graph_verify(int argc, const char **argv)
 	int fd;
 	struct stat st;
 	int flags = 0;
-
+	struct option *options = NULL;
 	static struct option builtin_commit_graph_verify_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			   N_("dir"),
-			   N_("the object directory to store the graph")),
 		OPT_BOOL(0, "shallow", &opts.shallow,
 			 N_("if the commit-graph is split, only verify the tip file")),
-		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
 		OPT_END(),
 	};
+	options = parse_options_dup(builtin_commit_graph_verify_options);

Another nitpick, but I'd rather see the initialization of "options" and
its declaration be on the same line, after declaring
builtin_commit_graph_verify_options.

As you noted in your own reply "the NULL initialization is important",
or more specifically: We're doing this dance here (and in other existing
code, e.g. checkout.c) to trampoline from the stack ot the heap.

quoted

+	options = add_common_options(options);

 	trace2_cmd_mode("verify");

 	opts.progress = isatty(2);
 	argc = parse_options(argc, argv, NULL,
-			     builtin_commit_graph_verify_options,
+			     options,
 			     builtin_commit_graph_verify_usage, 0);

 	if (!opts.obj_dir)

@@ -205,11 +218,8 @@ static int graph_write(int argc, const char **argv)
 	int result = 0;
 	enum commit_graph_write_flags flags = 0;
 	struct progress *progress = NULL;
-
+	struct option *options = NULL;
 	static struct option builtin_commit_graph_write_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			N_("dir"),
-			N_("the object directory to store the graph")),
 		OPT_BOOL(0, "reachable", &opts.reachable,
 			N_("start walk at all refs")),
 		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,

@@ -220,7 +230,6 @@ static int graph_write(int argc, const char **argv)
 			N_("include all commits already in the commit-graph file")),
 		OPT_BOOL(0, "changed-paths", &opts.enable_changed_paths,
 			N_("enable computation for changed paths")),
-		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
 		OPT_CALLBACK_F(0, "split", &write_opts.split_flags, NULL,
 			N_("allow writing an incremental commit-graph file"),
 			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,

@@ -236,6 +245,8 @@ static int graph_write(int argc, const char **argv)
 			0, write_option_max_new_filters),
 		OPT_END(),
 	};
+	options = parse_options_dup(builtin_commit_graph_write_options);
+	options = add_common_options(options);

 	opts.progress = isatty(2);
 	opts.enable_changed_paths = -1;

@@ -249,7 +260,7 @@ static int graph_write(int argc, const char **argv)
 	git_config(git_commit_graph_write_config, &opts);

 	argc = parse_options(argc, argv, NULL,
-			     builtin_commit_graph_write_options,
+			     options,
 			     builtin_commit_graph_write_usage, 0);

 	if (opts.reachable + opts.stdin_packs + opts.stdin_commits > 1)

@@ -312,12 +323,8 @@ static int graph_write(int argc, const char **argv)

 int cmd_commit_graph(int argc, const char **argv, const char *prefix)
 {
-	static struct option builtin_commit_graph_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			N_("dir"),
-			N_("the object directory to store the graph")),
-		OPT_END(),
-	};
+	struct option *no_options = parse_options_dup(NULL);

Hmm. Why bother calling add_common_options at all here?

I assume you mean in this line just below what you quoted:

    struct option *builtin_commit_graph_options = add_common_options(no_options);

Do you mean why not do the whole thing in graph_{verify,write}() and
only show the usage if we fail here?

Yeah arguably that makes more sense, but I wanted to just focus on
refactoring existing behavior & get rid of the copy/pasted options
rather than start a bigger rewrite of "maybe we shouldn't show this
rather useless help info if we die here....".