[GSoC][RFC PATCH v4 0/5] Add refs list subcommand

[Meet Soni <meetsoni3017@gmail.com>]

Hello everyone,

This is the fourth version of the patch series that introduces the git
refs list subcommand.

Changes in v4:

  - Implemented architectural refactoring. The core logic of
    for-each-ref now resides in a shared helper function, and both
    for-each-ref and refs list have been simplified to thin wrappers
    around it.

  - The usage strings have also been refactored. The common options
    are now defined in a shared macro in a new for-each-ref.h header.

  - The patch series has been further split to cleanly separate the
    preparatory refactoring commits (for both the C code and the
    AsciiDoc documentation) from the commit that introduces the new
    feature.

  - As a beneficial side-effect of unifying the usage strings, this
    series now fixes a pre-existing inconsistency between the --help
    output and the man page for for-each-ref. This allows a known
    breakage for it in the t0450 documentation test to be removed.

---

(v1 cover-letter text)

This patch series introduces `git refs list` as a modern replacement for
`git for-each-ref`, as part of an effort to consolidate ref-related
functionality under a unified `git refs` command.

Git's ref-related operations are currently handled by several distinct
commands, such as `git show-ref`, `git for-each-ref`, `git update-ref`,
`git pack-refs`, etc. This distribution has a few practical drawbacks:

- Users need to rely on multiple commands for related tasks involving
  refs.

- The commands may differ slightly in behavior and option syntax,
  leading to inconsistency.

We propose a long-term consolidation effort to bring ref-related
subcommands under the umbrella of a single command: `git refs`.

The implementation of `git refs list` is functionally identical to `git
for-each-ref`. It reuses the same internal logic (cmd_for_each_ref) to
ensure complete backward compatibility. The purpose of this patch is not
to introduce new behavior but to provide an alternate entry point under
the consolidated `git refs` namespace.

The motivation behind this change is twofold:

- Consolidation: Centralizing ref-related operations makes them easier
  to discover, use, and maintain.

- Evolution: While the initial goal is parity with existing commands,
  this consolidation allows for careful reconsideration of which
  features are essential. Over time, we can:

  - Remove legacy or obscure options that are no longer needed.
  - Add improvements that wouldn't make sense to bolt onto legacy
    commands.
  - Offering a more consistent and user-friendly surface.

To verify backward compatibility, this patch also includes a test
`t/t1461-refs-list.sh`, which runs the full `t6300-for-each-ref.sh` test
using `git refs list`. The test uses ${GIT_REFS_LIST_CMD:-for-each-ref}
to allow substitution without duplicating tests.

This patch is deliberately conservative: it introduces no behavioral
changes and leaves `for-each-ref` untouched. The goal is to lay
groundwork and demonstrate viability of ref consolidation within `git
refs`.

Going forward, I'd like to initiate a discussion on what the ideal
surface of `git refs list` should look like. Which options and features
from `for-each-ref` should be carried over? Are there any that are
obsolete or overly niche? What improvements might be worth considering
now that we have a new, consolidated interface?

Feedback on this, especially from those who rely on `for-each-ref` in
scripts or tooling would be very helpful.

Meet Soni (5):
  doc: factor out common option
  builtin/for-each-ref: factor out core logic into a helper
  builtin/refs: add list subcommand
  t6300: refactor tests to be shareable
  t: add test for git refs list subcommand

 Documentation/for-each-ref-options.adoc |   79 +
 Documentation/git-for-each-ref.adoc     |   80 +-
 Documentation/git-refs.adoc             |   16 +
 builtin/for-each-ref.c                  |   35 +-
 builtin/refs.c                          |   14 +
 for-each-ref.h                          |   24 +
 t/for-each-ref-tests.sh                 | 2141 +++++++++++++++++++++++
 t/meson.build                           |    1 +
 t/t0450/adoc-help-mismatches            |    1 -
 t/t1461-refs-list.sh                    |    8 +
 t/t6300-for-each-ref.sh                 | 2140 +---------------------
 11 files changed, 2305 insertions(+), 2234 deletions(-)
 create mode 100644 Documentation/for-each-ref-options.adoc
 create mode 100644 for-each-ref.h
 create mode 100644 t/for-each-ref-tests.sh
 create mode 100755 t/t1461-refs-list.sh

Range-diff against v3:
1:  547b0bbf8f < -:  ---------- builtin/refs: add list subcommand
-:  ---------- > 1:  d2fa47a2b9 doc: factor out common option
-:  ---------- > 2:  5084db4d14 builtin/for-each-ref: factor out core logic into a helper
-:  ---------- > 3:  1a15cd454b builtin/refs: add list subcommand
2:  5d5057ff98 = 4:  29c41d682b t6300: refactor tests to be shareable
3:  b9cb9cdf48 = 5:  0fd1f714c9 t: add test for git refs list subcommand
-- 
2.34.1