[PATCH v6 00/10] parseopt: add subcommand autocorrection

Git currently provides auto-correction for builtins and aliases, but lacks this functionality for subcommands parsed via the parse-options API. Subcommands are also commands, and typos will occur, too. Like:

	git remote add-rul

So, this series introduces subcommand auto-correction.

By default, this implementation enables autocorrection for builtins with mandatory subcommands. However, for those using PARSE_OPT_SUBCOMMAND_OPTIONAL, autocorrection is skipped to avoid misinterpreting legitimate unknown arguments as mistyped subcommands.

To allow builtins with optional subcommands to explicitly opt in, this series adds the PARSE_OPT_SUBCOMMAND_AUTOCORRECT flag, and enables it for git-remote and git-notes.

Additionally, the existing autocorrection logic is extracted from help.c so subcommand handling can reuse the same config parsing and prompt/delay logic.

Some string literals are also combined so the full text is easier to grep for.

Changes in v6:
  - Adjust existing tests to fit subcommand autocorrection behavior
  - Change the similar subcommand hint exit code to 129

Changes in v5:
  - Make subcommand autocorrection behave the same as command
    autocorrection
  - Rename PARSE_OPT_SUBCOMMAND_AUTOCORR to
    PARSE_OPT_SUBCOMMAND_AUTOCORRECT
  - Adjust subcommand autocorrection tests to fit new behavior

Changes in v4:
  - Add missing files to Meson build
  - Change API prefix from autocorr to autocorrect
  - Split the commit that moves tty code
  - Add API documentation
  - Use standard Damerau-Levenshtein distance and common practice
    fuzziness thresholds
  - Rename AUTOCORRECT_HINTONLY to AUTOCORRECT_HINT
  - Change commit subject prefix for tests from "help:" to "parseopt:"
  - Fix coding style issues

Changes in v3:
  - Align with the coding guildline
  - Split patch so diffs don't get hidden by code movement
  - Improve commit messages

Changes in v2:
  - Reword the explanation of default autocorrection behavior

Jiamu Sun (10):
  parseopt: extract subcommand handling from parse_options_step()
  help: make autocorrect handling reusable
  help: move tty check for autocorrection to autocorrect.c
  autocorrect: use mode and delay instead of magic numbers
  autocorrect: rename AUTOCORRECT_SHOW to AUTOCORRECT_HINT
  autocorrect: provide config resolution API
  parseopt: autocorrect mistyped subcommands
  parseopt: enable subcommand autocorrection for git-remote and
    git-notes
  parseopt: add tests for subcommand autocorrection
  doc: document autocorrect API

 Makefile                          |   1 +
 autocorrect.c                     |  89 +++++++++++++++
 autocorrect.h                     |  36 ++++++
 builtin/notes.c                   |  10 +-
 builtin/remote.c                  |  12 +-
 help.c                            | 120 ++++----------------
 meson.build                       |   1 +
 parse-options.c                   | 183 +++++++++++++++++++++++-------
 parse-options.h                   |   1 +
 t/meson.build                     |   1 +
 t/t0040-parse-options.sh          |   5 +-
 t/t7900-maintenance.sh            |   4 +-
 t/t9004-autocorrect-subcommand.sh |  58 ++++++++++
 13 files changed, 366 insertions(+), 155 deletions(-)
 create mode 100644 autocorrect.c
 create mode 100644 autocorrect.h
 create mode 100755 t/t9004-autocorrect-subcommand.sh

base-commit: f65aba1e87db64413b6d1ed5ae5a45b5a84a0997