[PATCH v4 07/10] parseopt: autocorrect mistyped subcommands
From: Jiamu Sun <hidden>
Date: 2026-03-16 15:36:51
Subsystem:
the rest · Maintainer:
Linus Torvalds
Try to autocorrect the mistyped mandatory subcommand before showing an error and exiting. Subcommands parsed with PARSE_OPT_SUBCOMMAND_OPTIONAL are skipped. Use standard Damerau-Levenshtein distance (weights 1, 1, 1, 1) to establish a predictable, mathematically sound baseline. Scale the allowed edit distance based on input length to prevent false positives on short commands, following common practice for fuzziness thresholds (e.g., Elasticsearch's AUTO fuzziness): - Length 0-2: 0 edits allowed - Length 3-5: 1 edit allowed - Length 6+: 2 edits allowed Signed-off-by: Jiamu Sun <redacted> --- parse-options.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 78 insertions(+), 3 deletions(-)
diff --git a/parse-options.c b/parse-options.c
index 02a4f00919f6..1f1b72762790 100644
--- a/parse-options.c
+++ b/parse-options.c@@ -6,6 +6,8 @@ #include "strbuf.h" #include "string-list.h" #include "utf8.h" +#include "autocorrect.h" +#include "levenshtein.h" static int disallow_abbreviated_options;
@@ -622,13 +624,77 @@ static int parse_subcommand(const char *arg, const struct option *options) return -1; } +static void find_subcommands(struct string_list *list, + const struct option *options) +{ + for (; options->type != OPTION_END; options++) { + if (options->type == OPTION_SUBCOMMAND) + string_list_append(list, options->long_name); + } +} + +static int similar_enough(const char *cmd, unsigned int edit) +{ + size_t len = strlen(cmd); + unsigned int allowed = len < 3 ? 0 : len < 6 ? 1 : 2; + + return edit <= allowed; +} + +static const char *autocorrect_subcommand(const char *cmd, + struct string_list *cmds) +{ + struct autocorrect autocorrect = { 0 }; + unsigned int min = UINT_MAX; + unsigned int ties = 0; + struct string_list_item *cand; + struct string_list_item *best = NULL; + + autocorrect_resolve(&autocorrect); + + /* + * Builtin subcommands are small enough that printing them all via + * usage_with_options() is sufficient. Therefore, AUTOCORRECT_HINT + * acts like AUTOCORRECT_NEVER. + */ + if (autocorrect.mode == AUTOCORRECT_HINT || + autocorrect.mode == AUTOCORRECT_NEVER) + return NULL; + + for_each_string_list_item(cand, cmds) { + unsigned int edit = levenshtein(cmd, cand->string, 1, 1, 1, 1); + + if (edit < min) { + min = edit; + best = cand; + ties = 0; + } else if (edit == min) { + ties++; + } + } + + if (!ties && similar_enough(cmd, min)) { + fprintf_ln(stderr, + _("WARNING: You called a subcommand named '%s', which does not exist."), + cmd); + + autocorrect_confirm(&autocorrect, best->string); + return best->string; + } + + return NULL; +} + static enum parse_opt_result handle_subcommand(struct parse_opt_ctx_t *ctx, const char *arg, const struct option *options, const char * const usagestr[]) { - int err = parse_subcommand(arg, options); + int err; + const char *assumed; + struct string_list cmds = STRING_LIST_INIT_NODUP; + err = parse_subcommand(arg, options); if (!err) return PARSE_OPT_SUBCOMMAND;
@@ -641,8 +707,17 @@ static enum parse_opt_result handle_subcommand(struct parse_opt_ctx_t *ctx, if (ctx->flags & PARSE_OPT_SUBCOMMAND_OPTIONAL) return PARSE_OPT_DONE; - error(_("unknown subcommand: `%s'"), arg); - usage_with_options(usagestr, options); + find_subcommands(&cmds, options); + assumed = autocorrect_subcommand(arg, &cmds); + + if (!assumed) { + error(_("unknown subcommand: `%s'"), arg); + usage_with_options(usagestr, options); + } + + string_list_clear(&cmds, 0); + parse_subcommand(assumed, options); + return PARSE_OPT_SUBCOMMAND; } static void check_typos(const char *arg, const struct option *options)
--
2.53.0