[PATCH v2 0/5] commit-graph: usage fixes

This set of trivial fixes to commit-graph usage was submitted originally back in February as https://lore.kernel.org/git/20210215184118.11306-1-avarab@gmail.com/

I omitted the In-Reply-To in the header because this was deep in an unrelated thread.

In the meantime Taylor's similar changes to the midx code landed (the original v1 was a "hey, here's how you can do this with parse_options()" on my part to him).

I did some changes based on feedback on the v1, but didn't pick up all the suggestions, it was mostly subjective, so let's see what people think this time around.

Ævar Arnfjörð Bjarmason (5):
  commit-graph: define common usage with a macro
  commit-graph: remove redundant handling of -h
  commit-graph: use parse_options_concat()
  commit-graph: early exit to "usage" on !argc
  commit-graph: show usage on "commit-graph [write|verify] garbage"

 builtin/commit-graph.c  | 95 +++++++++++++++++++++++------------------
 t/t5318-commit-graph.sh |  7 +++
 2 files changed, 60 insertions(+), 42 deletions(-)

Range-diff against v1:
1:  742648756a5 ! 1:  0b0bb04ecf5 commit-graph: define common usage with a macro
    @@ Commit message
         information, see e.g. 809e0327f5 (builtin/commit-graph.c: introduce
         '--max-new-filters=<n>', 2020-09-18).
     
    +    See b25b727494f (builtin/multi-pack-index.c: define common usage with
    +    a macro, 2021-03-30) for another use of this pattern (but on-list this
    +    one came first).
    +
         Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
      ## builtin/commit-graph.c ##
2:  497b6cbc9a5 = 2:  6f386fc32c8 commit-graph: remove redundant handling of -h
3:  fd1deaa3c99 ! 3:  2e7d9b0b8e4 commit-graph: use parse_options_concat()
    @@ builtin/commit-graph.c: static struct opts_commit_graph {
      					 const char *obj_dir)
      {
     @@ builtin/commit-graph.c: 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"),
    @@ builtin/commit-graph.c: static int graph_verify(int argc, const char **argv)
     -		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
      		OPT_END(),
      	};
    -+	options = parse_options_dup(builtin_commit_graph_verify_options);
    ++	struct option *options = parse_options_dup(builtin_commit_graph_verify_options);
     +	options = add_common_options(options);
      
      	trace2_cmd_mode("verify");
    @@ builtin/commit-graph.c: static int graph_verify(int argc, const char **argv)
      
      	if (!opts.obj_dir)
     @@ builtin/commit-graph.c: 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"),
    @@ builtin/commit-graph.c: 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);
    ++	struct option *options = parse_options_dup(builtin_commit_graph_write_options);
     +	options = add_common_options(options);
      
      	opts.progress = isatty(2);
4:  3d4a1fb6680 ! 4:  d776424e8c8 commit-graph: refactor dispatch loop for style
    @@ Metadata
     Author: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
      ## Commit message ##
    -    commit-graph: refactor dispatch loop for style
    +    commit-graph: early exit to "usage" on !argc
     
    -    I think it's more readable to have one if/elsif/else chain here than
    -    the code this replaces.
    +    Rather than guarding all of the !argc with an additional "if" arm
    +    let's do an early goto to "usage". This also makes it clear that
    +    "save_commit_buffer" is not needed in this case.
     
         Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
     
      ## builtin/commit-graph.c ##
     @@ builtin/commit-graph.c: int cmd_commit_graph(int argc, const char **argv, const char *prefix)
    + 			     builtin_commit_graph_options,
    + 			     builtin_commit_graph_usage,
    + 			     PARSE_OPT_STOP_AT_NON_OPTION);
    ++	if (!argc)
    ++		goto usage;
      
      	save_commit_buffer = 0;
      
    @@ builtin/commit-graph.c: int cmd_commit_graph(int argc, const char **argv, const
     -		if (!strcmp(argv[0], "write"))
     -			return graph_write(argc, argv);
     -	}
    --
    --	usage_with_options(builtin_commit_graph_usage,
    --			   builtin_commit_graph_options);
    -+	if (argc && !strcmp(argv[0], "verify"))
    ++	if (!strcmp(argv[0], "verify"))
     +		return graph_verify(argc, argv);
     +	else if (argc && !strcmp(argv[0], "write"))
     +		return graph_write(argc, argv);
    -+	else
    -+		usage_with_options(builtin_commit_graph_usage,
    -+				   builtin_commit_graph_options);
    + 
    ++usage:
    + 	usage_with_options(builtin_commit_graph_usage,
    + 			   builtin_commit_graph_options);
      }
5:  e8481a0932a = 5:  57ffd5812d6 commit-graph: show usage on "commit-graph [write|verify] garbage"