[PATCH v6 0/5] implement branch --recurse-submodules

[Glen Choo <chooglen@google.com>]

Submodule branching RFC:
https://lore.kernel.org/git/kl6lv912uvjv.fsf@chooglen-macbookpro.roam.corp.google.com/

Original Submodule UX RFC/Discussion:
https://lore.kernel.org/git/YHofmWcIAidkvJiD@google.com/

Contributor Summit submodules Notes:
https://lore.kernel.org/git/nycvar.QRO.7.76.6.2110211148060.56@tvgsbejvaqbjf.bet/

Submodule UX overhaul updates:
https://lore.kernel.org/git/?q=Submodule+UX+overhaul+update

This series implements branch --recurse-submodules as laid out in the
Submodule branching RFC (linked above). If there are concerns about the
UX/behavior, I would appreciate feedback on the RFC thread as well :)

v6 fixes v5's bad rebase; it was based off a merge commit in 'seen'
instead of js/branch-track-inherit. Since v5 is mostly a no-op, I will
also include a range-diff against v4, which is the last version that
anyone except Junio would care about.

This version is based off Josh's js/branch-track-inherit v7. Because that
is not yet in 'seen', I applied those patches onto abe6bb3905 (The first
batch to start the current cycle, 2021-11-29). The base commit can be
found at https://github.com/chooglen/git/tree/js/branch-track-inherit-v7.
I really hope I got right this time, but if not, hopefully the paper
trail is obvious.

Future work:
* `git branch -d --recurse-submodules` so that users can clean up
  extraneous branches.
* `git [checkout | switch] --recurse-submodules` +
  submodule.propagateBranches so that users can actually checkout the
  branches.
* After [1], it seems clear that --recurse-submodules parsing could
  really benefit from some standardization. It's not obvious which
  RECURSE_SUBMODULE_* enums are applicable to which commands, and there
  is no way to distinguish between an explicit --recurse-submodules from
  argv vs submodule.recurse from the config.

  I chose not to use them in this series because their usage is already
  inconsistent (grep.c doesn't use them either), and it would be _more_
  confusing to use the enum (handling RECURSE_SUBMODULES_DEFAULT = 1 is
  trickier than boolean 0 and 1).

  At this point, I think it would be too noisy to introduce the enum,
  but this would be a nice cleanup to do later.
* As documented in branch.c, we create branches using a child process
  only because install_branch_config() does not support submodules.
  It should be possible to remove the child process once we make the
  appropriate changes to config.c. I attempted this in [2] but chose to
  punt it because it was too time-consuming at the time.

Changes since v5:
* Rebase onto v7 of js/branch-track-inherit
  (https://lore.kernel.org/git/cover.1639717481.git.steadmon@google.com)

Changes since v4:
* Rebase correctly onto 'gitster/seen^{/^Merge branch .js/branch-track-inherit.}'
  (see base-commit) as suggested in [3] (thanks Junio!)
* These patches were also verified on top of 'next'.

Changes since v3:
* Split up the old patch 1. Patch 1 had a big diff because it used to
  move lines, remove dead code and introduce repo_* functions (thanks
  Jonathan!)
** repo_* functions have been dropped; they added noise and are not
   necessary for correctness.
* Use a new, harder-to-misuse function in --set-upstream-to,
  dwim_and_setup_tracking(). Now, setup_tracking() never does DWIM and
  dwim_and_setup_tracking() always does DWIM.
* Move create_branch() dry_run to its own patch.
* Fix an oversight where submodules in subtrees were ignored. This was
  because submodules_of_tree() and tree_entry() didn't recurse into
  subtrees. Test this accordingly (thanks Jonathan!).
* cmd_branch() possible actions are more consistently ordered.
* Documentation fixes (thanks Philippe!).
* Additional comments and explanation.
* Drop patch 5 (optional cleanup).
* Rebase onto js/branch-track-inherit v6.

Changes since v2:
* Rebase onto js/branch-track-inherit. This series should continue to be
  the case going forward.
* Patch 1 has a smaller diff because the introduction of
  validate_branch_start() no longer changes the function order thanks to a
  forward declaration. This artificial forward declaration is removed in a
  patch 2 (which can just be squashed into patch 1).
* Optional cleanup: fix questionable exit codes in patch 5.

Changes since v1:
* Move the functionality of "git branch --dry-run" into "git submodule-helper create-branch --dry-run"
* Add more fields to the submodules_of_tree() struct to reduce the
  number of allocations made by the caller. Move this functionality
  to patch 3 (formerly patch 4) and drop patch 1.
* Make submodules_of_tree() ignore inactive submodules
* Structure the output of the submodules a bit better by adding prefixes
  to the child process' output (instead of inconsistently indenting the
  output).
** I wasn't able to find a good way to interleave stdout/stderr
   correctly, so a less-than-desirable workaround was to route the child
   process output to stdout/stderr depending on the exit code.
** Eventually, I would like to structure the output of submodules in a
   report, as Ævar suggested. But at this stage, I think that it's
   better to spend time getting user feedback on the submodules
   branching UX and it'll be easier to standardize the output when we've
   implemented more of the UX :)

[1] https://lore.kernel.org/git/kl6lbl1p9zjf.fsf@chooglen-macbookpro.roam.corp.google.com/
[2] https://lore.kernel.org/git/kl6lv90ytd4v.fsf@chooglen-macbookpro.roam.corp.google.com/
[3] https://lore.kernel.org/git/xmqqlf0lz6os.fsf@gitster.g 

Glen Choo (5):
  branch: move --set-upstream-to behavior to dwim_and_setup_tracking()
  branch: make create_branch() always create a branch
  branch: add a dry_run parameter to create_branch()
  builtin/branch: clean up action-picking logic in cmd_branch()
  branch: add --recurse-submodules option for branch creation

 Documentation/config/advice.txt    |   3 +
 Documentation/config/submodule.txt |  24 ++-
 Documentation/git-branch.txt       |  11 +-
 advice.c                           |   1 +
 advice.h                           |   1 +
 branch.c                           | 257 ++++++++++++++++++++-----
 branch.h                           |  57 +++++-
 builtin/branch.c                   |  70 +++++--
 builtin/checkout.c                 |   3 +-
 builtin/submodule--helper.c        |  38 ++++
 submodule-config.c                 |  60 ++++++
 submodule-config.h                 |  34 ++++
 submodule.c                        |  11 +-
 submodule.h                        |   3 +
 t/t3200-branch.sh                  |  17 ++
 t/t3207-branch-submodule.sh        | 291 +++++++++++++++++++++++++++++
 16 files changed, 805 insertions(+), 76 deletions(-)
 create mode 100755 t/t3207-branch-submodule.sh

Range-diff against v5:
1:  a9d1108b3e ! 1:  29669c57b4 branch: move --set-upstream-to behavior to dwim_and_setup_tracking()
    @@ branch.c: static void setup_tracking(const char *new_ref, const char *orig_ref,
      
      	if (tracking.matches > 1)
     @@ branch.c: static void setup_tracking(const char *new_ref, const char *orig_ref,
    - 			      tracking.srcs) < 0)
    + 				tracking.remote, tracking.srcs) < 0)
      		exit(-1);
      
     +cleanup:
    @@ branch.c: N_("\n"
     @@ branch.c: void create_branch(struct repository *r,
      
      	if ((commit = lookup_commit_reference(r, &oid)) == NULL)
    - 		die(_("not a valid branch point: '%s'"), start_name);
    + 		die(_("Not a valid branch point: '%s'."), start_name);
     -	oidcpy(&oid, &commit->object.oid);
     +	if (out_real_ref)
     +		*out_real_ref = real_ref ? xstrdup(real_ref) : NULL;
2:  c543c1412a = 2:  ac2532a953 branch: make create_branch() always create a branch
3:  dddd434d7a = 3:  a0ed3fa438 branch: add a dry_run parameter to create_branch()
4:  41cca3bd52 = 4:  ebded31c96 builtin/branch: clean up action-picking logic in cmd_branch()
5:  540eeab183 ! 5:  0a7ec6ee75 branch: add --recurse-submodules option for branch creation
    @@ t/t3207-branch-submodule.sh (new)
     +		test_must_fail git rev-parse branch-a &&
     +
     +		cat >expected <<-EOF &&
    -+		submodule ${SQ}sub${SQ}: fatal: a branch named ${SQ}branch-a${SQ} already exists
    ++		submodule ${SQ}sub${SQ}: fatal: A branch named ${SQ}branch-a${SQ} already exists.
     +		fatal: submodule ${SQ}sub${SQ}: cannot create branch ${SQ}branch-a${SQ}
     +		EOF
     +		test_cmp expected actual

base-commit: e1c6879cf24f90693ca108542ec1db970764e1dc
-- 
2.33.GIT