Subject: [GSoC][RFC PATCH v4 2/5] builtin/for-each-ref: factor out core logic into a helper

From: Meet Soni <[email-masked]>
Date: Thu, 31 Jul 2025 14:30:37 +0530

The implementation of `git for-each-ref` is monolithic within
`cmd_for_each_ref()`, making it impossible to share its logic with other
commands. To enable code reuse for the upcoming `git refs list`
subcommand, refactor the core logic into a shared helper function.

Introduce a new `for-each-ref.h` header to define the public interface
for this shared logic. It contains the declaration for a new helper
function, `for_each_ref_core()`, and a macro for the common usage
options.

Move the option parsing, filtering, and formatting logic from
`cmd_for_each_ref()` into a new helper function named
`for_each_ref_core()`. This helper is made generic by accepting the
command's usage string as a parameter.

The original `cmd_for_each_ref()` is simplified to a thin wrapper that
is only responsible for defining its specific usage array and calling
the shared helper.

Mentored-by: Patrick Steinhardt <[email-masked]>
Mentored-by: shejialuo <[email-masked]>
Mentored-by: Karthik Nayak <[email-masked]>
Signed-off-by: Meet Soni <[email-masked]>
---
 builtin/for-each-ref.c       | 35 +++++++++++++++++++----------------
 for-each-ref.h               | 24 ++++++++++++++++++++++++
 t/t0450/adoc-help-mismatches |  1 -
 3 files changed, 43 insertions(+), 17 deletions(-)
 create mode 100644 for-each-ref.h

diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 3d2207ec77..bbc0e5ad1c 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -7,19 +7,9 @@
 #include "ref-filter.h"
 #include "strbuf.h"
 #include "strvec.h"
+#include "for-each-ref.h"
 
-static char const * const for_each_ref_usage[] = {
-	N_("git for-each-ref [<options>] [<pattern>]"),
-	N_("git for-each-ref [--points-at <object>]"),
-	N_("git for-each-ref [--merged [<commit>]] [--no-merged [<commit>]]"),
-	N_("git for-each-ref [--contains [<commit>]] [--no-contains [<commit>]]"),
-	NULL
-};
-
-int cmd_for_each_ref(int argc,
-		     const char **argv,
-		     const char *prefix,
-		     struct repository *repo)
+int for_each_ref_core(int argc, const char **argv, const char *prefix, struct repository *repo, const char *const *usage)
 {
 	struct ref_sorting *sorting;
 	struct string_list sorting_options = STRING_LIST_INIT_DUP;
@@ -67,17 +57,17 @@ int cmd_for_each_ref(int argc,
 	/* Set default (refname) sorting */
 	string_list_append(&sorting_options, "refname");
 
-	parse_options(argc, argv, prefix, opts, for_each_ref_usage, 0);
+	parse_options(argc, argv, prefix, opts, usage, 0);
 	if (format.array_opts.max_count < 0) {
 		error("invalid --count argument: `%d'", format.array_opts.max_count);
-		usage_with_options(for_each_ref_usage, opts);
+		usage_with_options(usage, opts);
 	}
 	if (HAS_MULTI_BITS(format.quote_style)) {
 		error("more than one quoting style?");
-		usage_with_options(for_each_ref_usage, opts);
+		usage_with_options(usage, opts);
 	}
 	if (verify_ref_format(&format))
-		usage_with_options(for_each_ref_usage, opts);
+		usage_with_options(usage, opts);
 
 	sorting = ref_sorting_options(&sorting_options);
 	ref_sorting_set_sort_flags_all(sorting, REF_SORTING_ICASE, icase);
@@ -111,3 +101,16 @@ int cmd_for_each_ref(int argc,
 	strvec_clear(&vec);
 	return 0;
 }
+
+int cmd_for_each_ref(int argc,
+		     const char **argv,
+		     const char *prefix,
+		     struct repository *repo)
+{
+	static char const * const for_each_ref_usage[] = {
+		N_("git for-each-ref " COMMON_USAGE_FOR_EACH_REF),
+		NULL
+	};
+
+	return for_each_ref_core(argc, argv, prefix, repo, for_each_ref_usage);
+}
diff --git a/for-each-ref.h b/for-each-ref.h
new file mode 100644
index 0000000000..06d5b123b3
--- /dev/null
+++ b/for-each-ref.h
@@ -0,0 +1,24 @@
+#ifndef FOR_EACH_REF_H
+#define FOR_EACH_REF_H
+
+/*
+ * Shared usage string for options common to git-for-each-ref(1)
+ * and git-refs-list(1). The command-specific part (e.g., "git refs list ")
+ * must be prepended by the caller.
+ */
+#define COMMON_USAGE_FOR_EACH_REF \
+	"[--count=<count>] [--shell|--perl|--python|--tcl]\n" \
+	"                         [(--sort=<key>)...] [--format=<format>]\n" \
+	"                         [--include-root-refs] [ --stdin | <pattern>... ]\n" \
+	"                         [--points-at=<object>]\n" \
+	"                         [--merged[=<object>]] [--no-merged[=<object>]]\n" \
+	"                         [--contains[=<object>]] [--no-contains[=<object>]]\n" \
+	"                         [--exclude=<pattern> ...]"
+
+/*
+ * The core logic for for-each-ref and its clones.
+ */
+int for_each_ref_core(int argc, const char **argv, const char *prefix,
+		      struct repository *repo, const char *const *usage);
+
+#endif /* FOR_EACH_REF_H */
diff --git a/t/t0450/adoc-help-mismatches b/t/t0450/adoc-help-mismatches
index 06b469bdee..2c6ecd5fc8 100644
--- a/t/t0450/adoc-help-mismatches
+++ b/t/t0450/adoc-help-mismatches
@@ -17,7 +17,6 @@ fast-export
 fast-import
 fetch-pack
 fmt-merge-msg
-for-each-ref
 format-patch
 fsck-objects
 fsmonitor--daemon
-- 
2.34.1