[PATCH v2] help.c: help.autocorrect=prompt waits for user action

From: Azeem Bande-Ali <me@azeemba.com>

If help.autocorrect is set to 'prompt', the user is prompted before the suggested action is executed.

Based on original patch by David Barr https://lore.kernel.org/git/1283758030-13345-1-git-send-email-david.barr@cordelta.com/

Signed-off-by: Azeem Bande-Ali <me@azeemba.com>
---
    New config for help.autocorrect to prompt user before action
    
    Changes since v1:
    
     * Use bullet lists for documenting the various settings now supported
       by help.autoCorrect
     * Add a check for an interactive terminal early to bail if the user has
       the "prompt" setting
     * Make the output more compact so the user can see the suggestion and
       the prompt in one line.

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1012%2Fazeemba%2Fautoprompt-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1012/azeemba/autoprompt-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1012

Range-diff vs v1:

 1:  7f72819b805 ! 1:  5819b872356 help.c: help.autocorrect=prompt waits for user action
     @@ Documentation/config/help.txt: help.format::
      -	is run immediately. If "never", suggestions are not shown at all. The
      -	default value is zero.
      +	to the error, git will try to suggest the correct command or even
     -+	run the intended command.
     -+	If this config value is 0, then the suggested command will be shown.
     -+	If it is positive, the suggested command will automatically
     -+	run after waiting for that many deciseconds (0.1 sec).
     -+	If it is "immediate", the suggested command will be
     -+	run immediately.
     -+	If it is "prompt", then the user will be shown the
     -+	suggestion and will be prompted for confirmation before the command
     -+	is run.
     -+	If it is "never", then no suggestion will be shown and no command
     -+	will be run.
     -+	0 is the default value for this config.
     ++	run the suggestion automatically. Possible config values are:
     ++	 - 0 (default): show the suggested command.
     ++	 - positive number: run the suggested command after specified
     ++deciseconds (0.1 sec).
     ++	 - "immediate": run the suggested command immediately.
     ++	 - "prompt": show the suggestion and prompt for confirmation to run
     ++the command.
     ++	 - "never": don't run or show any suggested command.
       
       help.htmlPath::
       	Specify the path where the HTML documentation resides. File system paths
     @@ help.c: static int git_unknown_cmd_config(const char *var, const char *value, vo
       			int v = git_config_int(var, value);
       			autocorrect = (v < 0)
      @@ help.c: const char *help_unknown_cmd(const char *cmd)
     + 
     + 	read_early_config(git_unknown_cmd_config, NULL);
     + 
     ++	/*
     ++	 * Disable autocorrection prompt in a non-interactive session
     ++	 */
     ++	if ((autocorrect == AUTOCORRECT_PROMPT) && (!isatty(0) || !isatty(2)))
     ++		autocorrect = AUTOCORRECT_NEVER;
     ++
     + 	if (autocorrect == AUTOCORRECT_NEVER) {
     + 		fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
     + 		exit(1);
     +@@ help.c: const char *help_unknown_cmd(const char *cmd)
       				   _("Continuing under the assumption that "
       				     "you meant '%s'."),
       				   assumed);
      -		else {
      +		else if (autocorrect == AUTOCORRECT_PROMPT) {
     -+			if (!isatty(STDIN_FILENO) | !isatty(STDERR_FILENO))
     -+				exit(1);
     -+
     -+			char *answer;
     -+			fprintf_ln(stderr, _("Assuming you meant: '%s'."),
     -+				   assumed);
     -+			answer = git_prompt(_("Continue? (y/N)"), PROMPT_ECHO);
     ++			char* answer;
     ++			struct strbuf msg = STRBUF_INIT;
     ++			strbuf_addf(&msg, _("Run '%s' instead? (y/N)"),
     ++				    assumed);
     ++			answer = git_prompt(msg.buf, PROMPT_ECHO);
     ++			strbuf_release(&msg);
      +			if (!(starts_with(answer, "y") ||
      +			      starts_with(answer, "Y")))
      +				exit(1);

 Documentation/config/help.txt | 16 +++++++++-------
 help.c                        | 22 +++++++++++++++++++++-
 2 files changed, 30 insertions(+), 8 deletions(-)