[PATCH v17 0/3] am: support --empty=(die|drop|keep) option and --allow-empty option to handle empty patches

Since that git has supported the --always option for the git-format-patch command to create a patch with an empty commit message, git-am should support applying and committing with empty patches.

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Changes since v1:

 1. add a case when not passing the --always option.
 2. rename the --always option to --allow-empty.

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Changes since v2:

 1. rename the --allow-empty option to --empty-commit.
 2. introduce three different strategies (die|skip|asis) when trying to
    record empty patches as empty commits.

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Changes since v3:

 1. generate the missed file for test cases.
 2. grep -f cannot be used under Mac OS.

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Changes since v4:

 1. rename the --empty-commit option to --empty.
 2. rename three different strategies (die|skip|asis) to die, drop and keep
    correspondingly.

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Changes since v5:

 1. throw an error when passing --empty option without value.

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Changes since v6:

 1. add i18n resources.

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Changes since v7:

 1. update code according to the seen branch.
 2. fix the wrong document of git-am.
 3. sign off commits by a real name.

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Changes since v8:

 1. update the committer's name with my real name to fix DCO of GGG.

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Changes since v9:

 1. imitate the signed name format of
    https://lore.kernel.org/git/pull.1143.git.git.1637347813367.gitgitgadget@gmail.com
    .

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Changes since v11:

 1. introduce an interactive option --allow-empty for git-am to record empty
    patches in the middle of an am session.

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Changes since v12:

 1. record the empty patch as an empty commit only when there are no
    changes.
 2. fix indentation problems.
 3. simplify "to keep recording" to "to record".
 4. add a test case for skipping empty patches via the --skip option.

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Changes since v13:

 1. add an additional description about the 'die' value.

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Changes since v14:

 1. reimplement the 'die' value and stop the whole session. (Expected a
    reroll)
 2. the --allow-empty option is a valid resume value only when: (Expected a
    reroll)
    * index has not changed
    * lacking a patch

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Changes since v15:

 1. rename "die" to "stop".

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Changes since v16:

 1. fix typo from "had" to "has" in the comment.

徐沛文 (Aleen) (3):
  doc: git-format-patch: describe the option --always
  am: support --empty=<option> to handle empty patches
  am: support --allow-empty to record specific empty patches

 Documentation/git-am.txt           |  16 ++++-
 Documentation/git-format-patch.txt |   6 +-
 builtin/am.c                       |  90 +++++++++++++++++++++----
 t/t4150-am.sh                      | 102 +++++++++++++++++++++++++++++
 t/t7512-status-help.sh             |   1 +
 wt-status.c                        |   3 +
 6 files changed, 203 insertions(+), 15 deletions(-)

base-commit: abe6bb3905392d5eb6b01fa6e54d7e784e0522aa
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1076%2Faleen42%2Fnext-v17
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1076/aleen42/next-v17
Pull-Request: https://github.com/gitgitgadget/git/pull/1076

Range-diff vs v16:

 1:  a524ca6adfa = 1:  a524ca6adfa doc: git-format-patch: describe the option --always
 2:  b9e03f2342b = 2:  b9e03f2342b am: support --empty=<option> to handle empty patches
 3:  abcdfa1b375 ! 3:  ea2dc088b37 am: support --allow-empty to record specific empty patches
     @@ builtin/am.c: next:
        * all the hard work, and we do not have to do any patch application. Just
      - * trust and commit what the user has in the index and working tree.
      + * trust and commit what the user has in the index and working tree. If `allow_empty`
     -+ * is true, commit as an empty commit when index had not changed and lacking a patch.
     ++ * is true, commit as an empty commit when index has not changed and lacking a patch.
        */
      -static void am_resolve(struct am_state *state)
      +static void am_resolve(struct am_state *state, int allow_empty)