On Tue, Oct 24, 2023 at 02:48:14PM -0400, Eric Sunshine wrote:

On Tue, Oct 24, 2023 at 9:11 AM Patrick Steinhardt [off-list ref] wrote:

quoted

It's not immediately obvious options which options are applicable to
what subcommand ni git-show-ref(1) because all options exist as global

s/ni/in/

quoted

state. This can easily cause confusion for the reader.

Refactor options for the `--exclude-existing` subcommand to be contained
in a separate structure. This structure is stored on the stack and
passed down as required. Consequentially, it clearly delimits the scope

s/Consequentially/Consequently/

quoted

of those options and requires the reader to worry less about global
state.

Signed-off-by: Patrick Steinhardt <redacted>
---

diff --git a/builtin/show-ref.c b/builtin/show-ref.c

@@ -95,6 +94,11 @@ static int add_existing(const char *refname,
+struct exclude_existing_options {
+       int enabled;
+       const char *pattern;
+};

Do we need this `enabled` flag? Can't the same be achieved by checking
whether `pattern` is NULL or not (see below)?

Yeah, we do. It's perfectly valid to pass `--exclude-existing` without
the optional pattern argument. We still want to use this mode in that
case, but don't populate the pattern.

An alternative would be to assign something like a sentinel value in
here. But I'd think that it's clearer to instead have an explicit
separate field for this.

quoted

@@ -104,11 +108,11 @@ static int add_existing(const char *refname,
-static int cmd_show_ref__exclude_existing(const char *match)
+static int cmd_show_ref__exclude_existing(const struct exclude_existing_options *opts)

Since you're renaming `match` to `opts->pattern`...

quoted

 {
-       int matchlen = match ? strlen(match) : 0;
+       int matchlen = opts->pattern ? strlen(opts->pattern) : 0;

... and since you're touching this line anyway, maybe it makes sense
to rename `matchlen` to `patternlen`?

Yes, let's do it. It's been more of an oversight rather than
intentional to keep the previous name.

quoted

@@ -124,11 +128,11 @@ static int cmd_show_ref__exclude_existing(const char *match)
-                       if (strncmp(ref, match, matchlen))
+                       if (strncmp(ref, opts->pattern, matchlen))

Especially since, as shown in this context, `matchlen` is really the
length of the _pattern_, not the length of the resulting _match_.

quoted

@@ -200,44 +204,46 @@ static int hash_callback(const struct option *opt, const char *arg, int unset)
 int cmd_show_ref(int argc, const char **argv, const char *prefix)
 {
        [...]
-       if (exclude_arg)
-               return cmd_show_ref__exclude_existing(exclude_existing_arg);
+       if (exclude_existing_opts.enabled)
+               return cmd_show_ref__exclude_existing(&exclude_existing_opts);

(continued from above) Can't this be handled without a separate `enabled` flag?

    if (exclude_existing_opts.pattern)
        ...

See the explanation above.

Patrick