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parse-options: don't emit "ambiguous option" for aliases

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Change the option parsing machinery so that e.g. "clone --recurs ..."
doesn't error out because "clone" understands both "--recursive" and
"--recurse-submodules" to mean the same thing.

Initially "clone" just understood --recursive until the
--recurses-submodules alias was added in ccdd3da652 ("clone: Add the
--recurse-submodules option as alias for --recursive",
2010-11-04). Since bb62e0a99f ("clone: teach --recurse-submodules to
optionally take a pathspec", 2017-03-17) the longer form has been
promoted to the default.

But due to the way the options parsing machinery works this resulted
in the rather absurd situation of:

    $ git clone --recurs [...]
    error: ambiguous option: recurs (could be --recursive or --recurse-submodules)

Add OPT_ALIAS() to express this link between two or more options and use
it in git-clone. Multiple aliases of an option could be written as

    OPT_ALIAS(0, "alias1", "original-name"),
    OPT_ALIAS(0, "alias2", "original-name"),
    ...

The current implementation is not exactly optimal in this case. But we
can optimize it when it becomes a problem. So far we don't even have two
aliases of any option.

A big chunk of code is actually from Junio C Hamano.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nguyễn Thái Ngọc Duy
2019-04-29 17:05:25 +07:00
committed by Junio C Hamano
parent 83232e3864
commit 5c387428f1
5 changed files with 164 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

143
parse-options.c
View File

@ -261,6 +261,35 @@ static enum parse_opt_result parse_short_opt(struct parse_opt_ctx_t *p,
return PARSE_OPT_UNKNOWN;
}
static int has_string(const char *it, const char **array)
{
while (*array)
if (!strcmp(it, *(array++)))
return 1;
return 0;
}
static int is_alias(struct parse_opt_ctx_t *ctx,
const struct option *one_opt,
const struct option *another_opt)
{
const char **group;
if (!ctx->alias_groups)
return 0;
if (!one_opt->long_name || !another_opt->long_name)
return 0;
for (group = ctx->alias_groups; *group; group += 3) {
/* it and other are from the same family? */
if (has_string(one_opt->long_name, group) &&
has_string(another_opt->long_name, group))
return 1;
}
return 0;
}
static enum parse_opt_result parse_long_opt(
struct parse_opt_ctx_t *p, const char *arg,
const struct option *options)
@ -298,7 +327,8 @@ again:
if (!(p->flags & PARSE_OPT_KEEP_UNKNOWN) &&
!strncmp(long_name, arg, arg_end - arg)) {
is_abbreviated:
if (abbrev_option) {
if (abbrev_option &&
!is_alias(p, abbrev_option, options)) {
/*
* If this is abbreviated, it is
* ambiguous. So when there is no
@ -447,6 +477,10 @@ static void parse_options_check(const struct option *opts)
if (opts->callback)
BUG("OPTION_LOWLEVEL_CALLBACK needs no high level callback");
break;
case OPTION_ALIAS:
BUG("OPT_ALIAS() should not remain at this point. "
"Are you using parse_options_step() directly?\n"
"That case is not supported yet.");
default:
; /* ok. (usually accepts an argument) */
}
@ -458,11 +492,10 @@ static void parse_options_check(const struct option *opts)
exit(128);
}
void parse_options_start(struct parse_opt_ctx_t *ctx,
int argc, const char **argv, const char *prefix,
const struct option *options, int flags)
static void parse_options_start_1(struct parse_opt_ctx_t *ctx,
int argc, const char **argv, const char *prefix,
const struct option *options, int flags)
{
memset(ctx, 0, sizeof(*ctx));
ctx->argc = argc;
ctx->argv = argv;
if (!(flags & PARSE_OPT_ONE_SHOT)) {
@ -484,6 +517,14 @@ void parse_options_start(struct parse_opt_ctx_t *ctx,
parse_options_check(options);
}
void parse_options_start(struct parse_opt_ctx_t *ctx,
int argc, const char **argv, const char *prefix,
const struct option *options, int flags)
{
memset(ctx, 0, sizeof(*ctx));
parse_options_start_1(ctx, argc, argv, prefix, options, flags);
}
static void show_negated_gitcomp(const struct option *opts, int nr_noopts)
{
int printed_dashdash = 0;
@ -575,6 +616,83 @@ static int show_gitcomp(const struct option *opts)
return PARSE_OPT_COMPLETE;
}
/*
* Scan and may produce a new option[] array, which should be used
* instead of the original 'options'.
*
* Right now this is only used to preprocess and substitue
* OPTION_ALIAS.
*/
static struct option *preprocess_options(struct parse_opt_ctx_t *ctx,
const struct option *options)
{
struct option *newopt;
int i, nr, alias;
int nr_aliases = 0;
for (nr = 0; options[nr].type != OPTION_END; nr++) {
if (options[nr].type == OPTION_ALIAS)
nr_aliases++;
}
if (!nr_aliases)
return NULL;
ALLOC_ARRAY(newopt, nr + 1);
COPY_ARRAY(newopt, options, nr + 1);
/* each alias has two string pointers and NULL */
CALLOC_ARRAY(ctx->alias_groups, 3 * (nr_aliases + 1));
for (alias = 0, i = 0; i < nr; i++) {
int short_name;
const char *long_name;
const char *source;
int j;
if (newopt[i].type != OPTION_ALIAS)
continue;
short_name = newopt[i].short_name;
long_name = newopt[i].long_name;
source = newopt[i].value;
if (!long_name)
BUG("An alias must have long option name");
for (j = 0; j < nr; j++) {
const char *name = options[j].long_name;
if (!name || strcmp(name, source))
continue;
if (options[j].type == OPTION_ALIAS)
BUG("No please. Nested aliases are not supported.");
/*
* NEEDSWORK: this is a bit inconsistent because
* usage_with_options() on the original options[] will print
* help string as "alias of %s" but "git cmd -h" will
* print the original help string.
*/
memcpy(newopt + i, options + j, sizeof(*newopt));
newopt[i].short_name = short_name;
newopt[i].long_name = long_name;
break;
}
if (j == nr)
BUG("could not find source option '%s' of alias '%s'",
source, newopt[i].long_name);
ctx->alias_groups[alias * 3 + 0] = newopt[i].long_name;
ctx->alias_groups[alias * 3 + 1] = options[j].long_name;
ctx->alias_groups[alias * 3 + 2] = NULL;
alias++;
}
return newopt;
}
static int usage_with_options_internal(struct parse_opt_ctx_t *,
const char * const *,
const struct option *, int, int);
@ -714,11 +832,16 @@ int parse_options(int argc, const char **argv, const char *prefix,
int flags)
{
struct parse_opt_ctx_t ctx;
struct option *real_options;
disallow_abbreviated_options =
git_env_bool("GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS", 0);
parse_options_start(&ctx, argc, argv, prefix, options, flags);
memset(&ctx, 0, sizeof(ctx));
real_options = preprocess_options(&ctx, options);
if (real_options)
options = real_options;
parse_options_start_1(&ctx, argc, argv, prefix, options, flags);
switch (parse_options_step(&ctx, options, usagestr)) {
case PARSE_OPT_HELP:
case PARSE_OPT_ERROR:
@ -741,6 +864,8 @@ int parse_options(int argc, const char **argv, const char *prefix,
}
precompose_argv(argc, argv);
free(real_options);
free(ctx.alias_groups);
return parse_options_end(&ctx);
}
@ -835,6 +960,12 @@ static int usage_with_options_internal(struct parse_opt_ctx_t *ctx,
fputc('\n', outfile);
pad = USAGE_OPTS_WIDTH;
}
if (opts->type == OPTION_ALIAS) {
fprintf(outfile, "%*s", pad + USAGE_GAP, "");
fprintf_ln(outfile, _("alias of --%s"),
(const char *)opts->value);
continue;
}
fprintf(outfile, "%*s%s\n", pad + USAGE_GAP, "", _(opts->help));
}
fputc('\n', outfile);