Allow disabling advice shown after merge conflicts

This series introduces a new config 'advice.mergeConflict' and uses it to allow disabling the advice shown when 'git rebase', 'git cherry-pick', 'git revert', 'git rebase --apply' and 'git am' stop because of conflicts.

Thanks everyone for the reviews!

Changes since v2:

* expanded the commit messages to explain why the tests for 'git rebase' do not need to be adjusted
* adjusted the wording of the new 'advice.mergeConflict' in the doc, as suggested by Kristoffer for uniformity with his series which is already merged to 'master' (b09a8839a4 (Merge branch 'kh/branch-ref-syntax-advice', 2024-03-15)).
* checked all new output manually and consequently adjusted the code in 1/2 to avoid a lonely 'hint: ' line.
* adjusted the addition in advice.h in 1/2 to put the new enum alphabetically, as noticed by Rubén.
* added misssing newlines in 2/2 as noticed by Phillip and tweaked by Junio.
* rebased on master (2953d95d40 (The eighth batch, 2024-03-15)), to avoid conflicts in 'Documentation/config/advice.txt' due to Kristoffer's merged series

Changes since v1:

* renamed the new advice to 'advice.mergeConflict' to make it non-sequencer specific
* added 2/2 which uses the advice in builtin/am, which covers 'git rebase --apply' and 'git am'

Note that the code path where 'git rebase --apply' stops because of conflicts is not covered by the tests but I tested it manually using this diff:

index 47534f1062..34eac2e6f4 100755
@@ -374,7 +374,7 @@ test_pull_autostash_fail ()
     echo conflicting >>seq.txt &&
     test_tick &&
     git commit -m "Create conflict" seq.txt &&
-	test_must_fail git pull --rebase . seq 2>err >out &&
+	test_must_fail git -c rebase.backend=apply pull --rebase . seq 2>err >out &&
     test_grep "Resolve all conflicts manually" err
 '
 

Philippe Blain (2):
sequencer: allow disabling conflict advice
builtin/am: allow disabling conflict advice

 Documentation/config/advice.txt |  2 ++
 advice.c                        |  1 +
 advice.h                        |  1 +
 builtin/am.c                    | 14 +++++++++-----
 sequencer.c                     | 33 ++++++++++++++++++---------------
 t/t3501-revert-cherry-pick.sh   |  1 +
 t/t3507-cherry-pick-conflict.sh |  2 ++
 t/t4150-am.sh                   |  8 ++++----
 t/t4254-am-corrupt.sh           |  2 +-
 9 files changed, 39 insertions(+), 25 deletions(-)

base-commit: 2953d95d402b6bff1a59c4712f4d46f1b9ea137f
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1682%2Fphil-blain%2Fsequencer-conflict-advice-v3
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1682/phil-blain/sequencer-conflict-advice-v3
Pull-Request: https://github.com/gitgitgadget/git/pull/1682

Range-diff vs v2:

1: a2ce6fd24c2 ! 1: 6005c1e9890 sequencer: allow disabling conflict advice
@@ Commit message
merge conflict through a new config 'advice.mergeConflict', which is named generically such that it can be used by other commands eventually.

+ Remove that final '\n' in the first hunk in sequencer.c to avoid an
+ otherwise empty 'hint: ' line before the line 'hint: Disable this
+ message with "git config advice.mergeConflict false"' which is
+ automatically added by 'advise_if_enabled'.
+
Note that we use 'advise_if_enabled' for each message in the second hunk in sequencer.c, instead of using 'if (show_hints && advice_enabled(...)', because the former instructs the user how to
@@ Commit message

Update the tests accordingly. Note that the body of the second test in t3507-cherry-pick-conflict.sh is enclosed in double quotes, so we must
- escape them in the added line.
+ escape them in the added line. Note that t5520-pull.sh, which checks
+ that we display the advice for 'git rebase' (via 'git pull --rebase')
+ does not have to be updated because it only greps for a specific line in
+ the advice message.

## Documentation/config/advice.txt ##
@@ Documentation/config/advice.txt: advice.*::
- Advice on how to set your identity configuration when
- your information is guessed from the system username and
- domain name.
+ Shown when the user's information is guessed from the
+ system username and domain name, to tell the user how to
+ set their identity configuration.
+ mergeConflict::
-+ Advice shown when various commands stop because of conflicts.
++ Shown when various commands stop because of conflicts.
nestedTag::
- Advice shown if a user attempts to recursively tag a tag object.
+ Shown when a user attempts to recursively tag a tag object.
pushAlreadyExists::

## advice.c ##
@@ advice.c: static struct {

## advice.h ##
@@ advice.h: enum advice_type {
+ ADVICE_GRAFT_FILE_DEPRECATED,
ADVICE_IGNORED_HOOK,
ADVICE_IMPLICIT_IDENTITY,
- ADVICE_NESTED_TAG,
+ ADVICE_MERGE_CONFLICT,
+ ADVICE_NESTED_TAG,
ADVICE_OBJECT_NAME_WARNING,
ADVICE_PUSH_ALREADY_EXISTS,
- ADVICE_PUSH_FETCH_FIRST,

## sequencer.c ##
@@ sequencer.c: static void print_advice(struct repository *r, int show_hint,
@@ sequencer.c: static void print_advice(struct repository *r, int show_hint,

if (msg) {
- advise("%s\n", msg);
-+ advise_if_enabled(ADVICE_MERGE_CONFLICT, "%s\n", msg);
++ advise_if_enabled(ADVICE_MERGE_CONFLICT, "%s", msg);
/*
* A conflict has occurred but the porcelain
* (typically rebase --interactive) wants to take care
2: 3235542cc6f ! 2: 73d07c8b6a7 builtin/am: allow disabling conflict advice

     @@ Commit message
          on stderr instead of stdout. In t4150, redirect stdout to 'out' and
          stderr to 'err', since this is less confusing. In t4254, as we are
          testing a specific failure mode of 'git am', simply disable the advice.
     +    Note that we are not testing that this advice is shown in 'git rebase'
     +    for the apply backend since 2ac0d6273f (rebase: change the default
     +    backend from "am" to "merge", 2020-02-15).
      
     +    Helped-by: Phillip Wood <[email protected]>
     +    Helped-by: Junio C Hamano <[email protected]>
          Signed-off-by: Philippe Blain <[email protected]>
      
       ## builtin/am.c ##
     @@ builtin/am.c: static const char *msgnum(const struct am_state *state)
       
      -		printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
      -		printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
     -+		strbuf_addf(&sb, _("When you have resolved this problem, run \"%s --continue\"."), cmdline);
     -+		strbuf_addf(&sb, _("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
     ++		strbuf_addf(&sb, _("When you have resolved this problem, run \"%s --continue\".\n"), cmdline);
     ++		strbuf_addf(&sb, _("If you prefer to skip this patch, run \"%s --skip\" instead.\n"), cmdline);
       
       		if (advice_enabled(ADVICE_AM_WORK_DIR) &&
       		    is_empty_or_missing_file(am_path(state, "patch")) &&
       		    !repo_index_has_changes(the_repository, NULL, NULL))
      -			printf_ln(_("To record the empty patch as an empty commit, run \"%s --allow-empty\"."), cmdline);
     -+			strbuf_addf(&sb, _("To record the empty patch as an empty commit, run \"%s --allow-empty\"."), cmdline);
     ++			strbuf_addf(&sb, _("To record the empty patch as an empty commit, run \"%s --allow-empty\".\n"), cmdline);
       
      -		printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
      +		strbuf_addf(&sb, _("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);

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