Tay Ray Chuan <rcta...@gmail.com> writes:
> If suggestions are available (based on Levenshtein distance) and if the
> terminal isatty(), present a prompt to the user to select one of the
> computed suggestions.
>
> In the case where there is a single suggestion, present the prompt
> "[Y/n]", such that "" (ie. the default), "y" and "Y" as input leads git
> to proceed executing the suggestion, while everything else (possibly
> "n") leads git to terminate.
>
> In the case where there are multiple suggestions, number the suggestions
> 1 to <n> (the number of suggestions), and accept an integer as input,
> while everything else (possibly "n") leads git to terminate. In this
> case there is no default; an empty input leads git to terminate. A
> sample run:
>
> $ git sh --pretty=oneline
> git: 'sh' is not a git command. See 'git --help'.
>
> Did you mean one of these?
> 1: show
> 2: push
> [N/1/2/...]
>
> This prompt is enabled only if help.autocorrect is set to ask; if unset,
> advise the user about this ability.
>
> Helped-by: Thomas Rast <tr...@student.ethz.ch>
> Signed-off-by: Tay Ray Chuan <rcta...@gmail.com>
> ---
>
> Changed in v3:
> - say do_* instead of shall_*
> - use new terminal interface
>
> Documentation/config.txt | 30 ++++++++++++++++-----
> advice.c | 2 ++
> advice.h | 1 +
> help.c | 68
> +++++++++++++++++++++++++++++++++++++++++++++---
> 4 files changed, 90 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/config.txt b/Documentation/config.txt
> index 0bcea8a..0bb175a 100644
> --- a/Documentation/config.txt
> +++ b/Documentation/config.txt
> @@ -177,6 +177,10 @@ advice.*::
> Advice shown when you used linkgit:git-checkout[1] to
> move to the detach HEAD state, to instruct how to create
> a local branch after the fact.
> + typoPrompt::
> + Upon a mistyped command, if 'help.autocorrect' is unset
> + advise that an interactive prompt can be displayed to
> + recover from the typo.
> --
I have a moderately strong reaction against this; "advice" is for
helping users out of common pitfalls, and we generally do not use
the "advise" mechanism to advertise random shiny features.
> @@ -1323,13 +1327,25 @@ help.format::
> ...
> help.autocorrect::
> + Specifies behaviour to recover from mistyped commands.
> ++
> +When set to `ask`, an interactive prompt is displayed, allowing the user
> +to select a suggested command for execution.
> ++
> +When set to `off`, no attempt to recover is made.
I notice that with the current code, even if help.autocorrect is set
to 0 to decline the guessing, we still get "did you mean one of
these" as long as the typo is similar enough to existing command.
I am guessing that this new value `off` is a way to remedy the
situation so that users can choose to decline any guessing, and just
get "no such subcommand". If that is the case, I think it is a vast
improvement.
> +If a number is given, it will be interpreted as the deciseconds (0.1
> +sec) to wait before automatically correcting and executing the mistyped
> +command, with the following behaviour:
> ++
> +* If more than one command can be deduced from the entered text, nothing
> + will be executed.
The above is from the original text, but I've always found the "can
be deduced" part hard to understand. It is a quite roundabout way
to say we cannot guess with confidence what the user meant and avoid
committing to a wrong guess. We may want to think a better way to
phrase the whole thing. Perhaps something along this line:
help.autocorrect::
When you mistype the name of a subcommand during an
interactive session, Git can try to guess which one
of available subcommands you meant (Git does not
waste cycles in a non-interactive session). This
configuration variable specifies what happens when
there are one or more subcommands that you are
likely to have meant.
- when set to 'ask', the choices are presented and
you can pick one to execute. If the command is
used non-interactively,
- when set to `off`, ...
This can be done after this patch series settles, of course.
> +* If the value of this option is negative, the corrected command will be
> + executed immediately.
> +* If the value is 0 - the command will be just shown but not executed.
> ++
> +The default is to display a message suggesting that this option be set
> +to `ask`, without attempting to recover (see `advice.typoPrompt`).
My comment to 'advice.typoPrompt' leads me to suggest not to change
the default to `ask`, but leave it to 0, and remove the change to
the following two files.
> diff --git a/advice.c b/advice.c
> diff --git a/advice.h b/advice.h
> diff --git a/help.c b/help.c
> index c4285a5..cc13b92 100644
> --- a/help.c
> +++ b/help.c
> @@ -7,6 +7,7 @@
> #include "string-list.h"
> #include "column.h"
> #include "version.h"
> +#include "compat/terminal.h"
>
> void add_cmdname(struct cmdnames *cmds, const char *name, int len)
> {
> @@ -233,12 +234,30 @@ int is_in_cmdlist(struct cmdnames *c, const char *s)
> }
>
> static int autocorrect;
> +static int do_advise = 1;
> +static int do_prompt;
> +static const char message_advice_prompt_ability[] =
> + N_("I can display an interactive prompt to proceed with one of the
> above\n"
> + "suggestions; if you wish me to do so, use\n"
> + "\n"
> + " git config --global help.autocorrect ask\n"
> + "\n"
> + "See 'git help config' and search for 'help.autocorrect' for
> further\n"
> + "information.\n");
> static struct cmdnames aliases;
Nah. No unsolicited advertisement, please.
> static int git_unknown_cmd_config(const char *var, const char *value, void
> *cb)
> {
> - if (!strcmp(var, "help.autocorrect"))
> - autocorrect = git_config_int(var,value);
> + if (!strcmp(var, "help.autocorrect") && value) {
> + do_advise = 0;
> + if (!strcasecmp(value, "off"))
> + ;
> + else if (!strcasecmp(value, "ask"))
> + do_prompt = 1;
> + else
> + autocorrect = git_config_int(var, value);
> + }
I think the current code diagnoses
[help]
autocorrect
that tries to say "true" as a syntax error. The above simply
ignores such an entry, no?
I was hoping "off" would be usable to bypass the whole levenstein
thing, but the above code does not suggest that the remainder of
this patch would be doing that X-<.
> @@ -366,13 +385,54 @@ const char *help_unknown_cmd(const char *cmd)
> fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git
> --help'."), cmd);
>
> if (SIMILAR_ENOUGH(best_similarity)) {
> + term_t term;
> +
> fprintf_ln(stderr,
> Q_("\nDid you mean this?",
> "\nDid you mean one of these?",
> n));
>
> - for (i = 0; i < n; i++)
> - fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
> + term = terminal_open();
> + if (!term || !do_prompt) {
> + for (i = 0; i < n; i++)
> + fprintf(stderr, "\t%s\n",
> main_cmds.names[i]->name);
It is the same as what is done with the current code, but if there
is no terminal available, do we even want to give this list?
> + if (isatty(2) && do_advise && advice_typo_prompt) {
> + fprintf(stderr, "\n");
> + advise(_(message_advice_prompt_ability));
> + }
Nah. No unsolicited advertisement, please.
> + } else if (n == 1) {
> + char *in;
> + const char *ret;
> + fprintf(stderr, "\t%s\n", main_cmds.names[0]->name);
> + in = terminal_prompt(term, "[Y/n] ", 1);
> + terminal_close(term);
> + switch (in[0]) {
> + case 'y': case 'Y': case 0:
> + ret = xstrdup(main_cmds.names[0]->name);
> + clean_cmdnames(&main_cmds);
> + return ret;
OK.
> + /* otherwise, don't do anything */
> + }
Indent the comment one level deeper?
> + } else {
> + char *in;
> + const char *ret;
> + int opt;
> + for (i = 0; i < n; i++)
Can we have too many choices for this "prompt" codepath to be
practical?
> + fprintf(stderr, "%d:\t%s\n", i + 1,
> main_cmds.names[i]->name);
> + in = terminal_prompt(term, "[N/1/2/...] ", 1);
Would it be too much trouble to spell the actual choices out here,
instead of the ugly "/..."?
> + terminal_close(term);
> + switch (in[0]) {
> + case 'n': case 'N': case 0:
> + ;
> + default:
> + opt = atoi(in);
> + if (0 < opt && opt <= n) {
> + ret = xstrdup(main_cmds.names[opt -
> 1]->name);
> + clean_cmdnames(&main_cmds);
> + return ret;
> + }
When the user mistypes the choice (perhaps say '8' when there are
only 7 choices available), it might be more helpful to loop here to
give him another chance. Would such an enhancement be worth it?
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