git/builtin/check-ignore.c
Elijah Newren 7ec8125fba check-ignore: fix documentation and implementation to match
check-ignore has two different modes, and neither of these modes has an
implementation that matches the documentation.  These modes differ in
whether they just print paths or whether they also print the final
pattern matched by the path.  The fix is different for both modes, so
I'll discuss both separately.

=== First (default) mode ===

The first mode is documented as:

    For each pathname given via the command-line or from a file via
    --stdin, check whether the file is excluded by .gitignore (or other
    input files to the exclude mechanism) and output the path if it is
    excluded.

However, it fails to do this because it did not account for negated
patterns.  Commands other than check-ignore verify exclusion rules via
calling

   ... -> treat_one_path() -> is_excluded() -> last_matching_pattern()

while check-ignore has a call path of the form:

   ... -> check_ignore()                    -> last_matching_pattern()

The fact that the latter does not include the call to is_excluded()
means that it is susceptible to to messing up negated patterns (since
that is the only significant thing is_excluded() adds over
last_matching_pattern()).  Unfortunately, we can't make it just call
is_excluded(), because the same codepath is used by the verbose mode
which needs to know the matched pattern in question.  This brings us
to...

=== Second (verbose) mode ===

The second mode, known as verbose mode, references the first in the
documentation and says:

    Also output details about the matching pattern (if any) for each
    given pathname. For precedence rules within and between exclude
    sources, see gitignore(5).

The "Also" means it will print patterns that match the exclude rules as
noted for the first mode, and also print which pattern matches.  Unless
more information is printed than just pathname and pattern (which is not
done), this definition is somewhat ill-defined and perhaps even
self-contradictory for negated patterns: A path which matches a negated
exclude pattern is NOT excluded and thus shouldn't be printed by the
former logic, while it certainly does match one of the explicit patterns
and thus should be printed by the latter logic.

=== Resolution ==

Since the second mode exists to find out which pattern matches given
paths, and showing the user a pattern that begins with a '!' is
sufficient for them to figure out whether the pattern is excluded, the
existing behavior is desirable -- we just need to update the
documentation to match the implementation (i.e. it is about printing
which pattern is matched by paths, not about showing which paths are
excluded).

For the first or default mode, users just want to know whether a pattern
is excluded.  As such, the existing documentation is desirable; change
the implementation to match the documented behavior.

Finally, also adjust a few tests in t0008 that were caught up by this
discrepancy in how negated paths were handled.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-18 15:28:58 -08:00

197 lines
5.1 KiB
C

#define USE_THE_INDEX_COMPATIBILITY_MACROS
#include "builtin.h"
#include "cache.h"
#include "config.h"
#include "dir.h"
#include "quote.h"
#include "pathspec.h"
#include "parse-options.h"
#include "submodule.h"
static int quiet, verbose, stdin_paths, show_non_matching, no_index;
static const char * const check_ignore_usage[] = {
"git check-ignore [<options>] <pathname>...",
"git check-ignore [<options>] --stdin",
NULL
};
static int nul_term_line;
static const struct option check_ignore_options[] = {
OPT__QUIET(&quiet, N_("suppress progress reporting")),
OPT__VERBOSE(&verbose, N_("be verbose")),
OPT_GROUP(""),
OPT_BOOL(0, "stdin", &stdin_paths,
N_("read file names from stdin")),
OPT_BOOL('z', NULL, &nul_term_line,
N_("terminate input and output records by a NUL character")),
OPT_BOOL('n', "non-matching", &show_non_matching,
N_("show non-matching input paths")),
OPT_BOOL(0, "no-index", &no_index,
N_("ignore index when checking")),
OPT_END()
};
static void output_pattern(const char *path, struct path_pattern *pattern)
{
char *bang = (pattern && pattern->flags & PATTERN_FLAG_NEGATIVE) ? "!" : "";
char *slash = (pattern && pattern->flags & PATTERN_FLAG_MUSTBEDIR) ? "/" : "";
if (!nul_term_line) {
if (!verbose) {
write_name_quoted(path, stdout, '\n');
} else {
if (pattern) {
quote_c_style(pattern->pl->src, NULL, stdout, 0);
printf(":%d:%s%s%s\t",
pattern->srcpos,
bang, pattern->pattern, slash);
}
else {
printf("::\t");
}
quote_c_style(path, NULL, stdout, 0);
fputc('\n', stdout);
}
} else {
if (!verbose) {
printf("%s%c", path, '\0');
} else {
if (pattern)
printf("%s%c%d%c%s%s%s%c%s%c",
pattern->pl->src, '\0',
pattern->srcpos, '\0',
bang, pattern->pattern, slash, '\0',
path, '\0');
else
printf("%c%c%c%s%c", '\0', '\0', '\0', path, '\0');
}
}
}
static int check_ignore(struct dir_struct *dir,
const char *prefix, int argc, const char **argv)
{
const char *full_path;
char *seen;
int num_ignored = 0, i;
struct path_pattern *pattern;
struct pathspec pathspec;
if (!argc) {
if (!quiet)
fprintf(stderr, "no pathspec given.\n");
return 0;
}
/*
* check-ignore just needs paths. Magic beyond :/ is really
* irrelevant.
*/
parse_pathspec(&pathspec,
PATHSPEC_ALL_MAGIC & ~PATHSPEC_FROMTOP,
PATHSPEC_SYMLINK_LEADING_PATH |
PATHSPEC_KEEP_ORDER,
prefix, argv);
die_path_inside_submodule(&the_index, &pathspec);
/*
* look for pathspecs matching entries in the index, since these
* should not be ignored, in order to be consistent with
* 'git status', 'git add' etc.
*/
seen = find_pathspecs_matching_against_index(&pathspec, &the_index);
for (i = 0; i < pathspec.nr; i++) {
full_path = pathspec.items[i].match;
pattern = NULL;
if (!seen[i]) {
int dtype = DT_UNKNOWN;
pattern = last_matching_pattern(dir, &the_index,
full_path, &dtype);
if (!verbose && pattern &&
pattern->flags & PATTERN_FLAG_NEGATIVE)
pattern = NULL;
}
if (!quiet && (pattern || show_non_matching))
output_pattern(pathspec.items[i].original, pattern);
if (pattern)
num_ignored++;
}
free(seen);
return num_ignored;
}
static int check_ignore_stdin_paths(struct dir_struct *dir, const char *prefix)
{
struct strbuf buf = STRBUF_INIT;
struct strbuf unquoted = STRBUF_INIT;
char *pathspec[2] = { NULL, NULL };
strbuf_getline_fn getline_fn;
int num_ignored = 0;
getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
while (getline_fn(&buf, stdin) != EOF) {
if (!nul_term_line && buf.buf[0] == '"') {
strbuf_reset(&unquoted);
if (unquote_c_style(&unquoted, buf.buf, NULL))
die("line is badly quoted");
strbuf_swap(&buf, &unquoted);
}
pathspec[0] = buf.buf;
num_ignored += check_ignore(dir, prefix,
1, (const char **)pathspec);
maybe_flush_or_die(stdout, "check-ignore to stdout");
}
strbuf_release(&buf);
strbuf_release(&unquoted);
return num_ignored;
}
int cmd_check_ignore(int argc, const char **argv, const char *prefix)
{
int num_ignored;
struct dir_struct dir;
git_config(git_default_config, NULL);
argc = parse_options(argc, argv, prefix, check_ignore_options,
check_ignore_usage, 0);
if (stdin_paths) {
if (argc > 0)
die(_("cannot specify pathnames with --stdin"));
} else {
if (nul_term_line)
die(_("-z only makes sense with --stdin"));
if (argc == 0)
die(_("no path specified"));
}
if (quiet) {
if (argc > 1)
die(_("--quiet is only valid with a single pathname"));
if (verbose)
die(_("cannot have both --quiet and --verbose"));
}
if (show_non_matching && !verbose)
die(_("--non-matching is only valid with --verbose"));
/* read_cache() is only necessary so we can watch out for submodules. */
if (!no_index && read_cache() < 0)
die(_("index file corrupt"));
memset(&dir, 0, sizeof(dir));
setup_standard_excludes(&dir);
if (stdin_paths) {
num_ignored = check_ignore_stdin_paths(&dir, prefix);
} else {
num_ignored = check_ignore(&dir, prefix, argc, argv);
maybe_flush_or_die(stdout, "ignore to stdout");
}
clear_directory(&dir);
return !num_ignored;
}