for-each-ref: add --stdin option

When a user wishes to input a large list of patterns to 'git
for-each-ref' (likely a long list of exact refs) there are frequently
system limits on the number of command-line arguments.

Add a new --stdin option to instead read the patterns from standard
input. Add tests that check that any unrecognized arguments are
considered an error when --stdin is provided. Also, an empty pattern
list is interpreted as the complete ref set.

When reading from stdin, we populate the filter.name_patterns array
dynamically as opposed to pointing to the 'argv' array directly. This is
simple when using a strvec, as it is NULL-terminated in the same way. We
then free the memory directly from the strvec.

Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 6da899c62964275a97854c0b338f83f51db4bdfe..ccdc2911bb9a3384941991cdeb87a07574949d86 100644 (file)
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -9,7 +9,8 @@ SYNOPSIS
 --------
 [verse]
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
-                  [(--sort=<key>)...] [--format=<format>] [<pattern>...]
+                  [(--sort=<key>)...] [--format=<format>]
+                  [ --stdin | <pattern>... ]
                   [--points-at=<object>]
                   [--merged[=<object>]] [--no-merged[=<object>]]
                   [--contains[=<object>]] [--no-contains[=<object>]]
@@ -32,6 +33,10 @@ OPTIONS
        literally, in the latter case matching completely or from the
        beginning up to a slash.
 
+--stdin::
+       If `--stdin` is supplied, then the list of patterns is read from
+       standard input instead of from the argument list.
+
 --count=<count>::
        By default the command shows all refs that match
        `<pattern>`.  This option makes it stop after showing

diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 6f62f40d1263f44f8977125d9d54eca76f101685..9df16cfb854f586d48ed430932296cdb2ff6c70e 100644 (file)
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -5,6 +5,7 @@
 #include "object.h"
 #include "parse-options.h"
 #include "ref-filter.h"
+#include "strvec.h"
 
 static char const * const for_each_ref_usage[] = {
        N_("git for-each-ref [<options>] [<pattern>]"),
@@ -25,6 +26,8 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
        struct ref_format format = REF_FORMAT_INIT;
        struct strbuf output = STRBUF_INIT;
        struct strbuf err = STRBUF_INIT;
+       int from_stdin = 0;
+       struct strvec vec = STRVEC_INIT;
 
        struct option opts[] = {
                OPT_BIT('s', "shell", &format.quote_style,
@@ -49,6 +52,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
                OPT_CONTAINS(&filter.with_commit, N_("print only refs which contain the commit")),
                OPT_NO_CONTAINS(&filter.no_commit, N_("print only refs which don't contain the commit")),
                OPT_BOOL(0, "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
+               OPT_BOOL(0, "stdin", &from_stdin, N_("read reference patterns from stdin")),
                OPT_END(),
        };
 
@@ -75,7 +79,23 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
        ref_sorting_set_sort_flags_all(sorting, REF_SORTING_ICASE, icase);
        filter.ignore_case = icase;
 
-       filter.name_patterns = argv;
+       if (from_stdin) {
+               struct strbuf line = STRBUF_INIT;
+
+               if (argv[0])
+                       die(_("unknown arguments supplied with --stdin"));
+
+               while (strbuf_getline(&line, stdin) != EOF)
+                       strvec_push(&vec, line.buf);
+
+               strbuf_release(&line);
+
+               /* vec.v is NULL-terminated, just like 'argv'. */
+               filter.name_patterns = vec.v;
+       } else {
+               filter.name_patterns = argv;
+       }
+
        filter.match_as_path = 1;
        filter_refs(&array, &filter, FILTER_REFS_ALL);
        ref_array_sort(sorting, &array);
@@ -97,5 +117,6 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
        free_commit_list(filter.with_commit);
        free_commit_list(filter.no_commit);
        ref_sorting_release(sorting);
+       strvec_clear(&vec);
        return 0;
 }

diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index c466fd989f168b0fc696e83516474f11040a58be..a58053a54c5c37a7cd32a6d855c9512098a96027 100755 (executable)
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -1464,4 +1464,41 @@ sig_crlf="$(printf "%s" "$sig" | append_cr; echo dummy)"
 sig_crlf=${sig_crlf%dummy}
 test_atom refs/tags/fake-sig-crlf contents:signature "$sig_crlf"
 
+test_expect_success 'git for-each-ref --stdin: empty' '
+       >in &&
+       git for-each-ref --format="%(refname)" --stdin <in >actual &&
+       git for-each-ref --format="%(refname)" >expect &&
+       test_cmp expect actual
+'
+
+test_expect_success 'git for-each-ref --stdin: fails if extra args' '
+       >in &&
+       test_must_fail git for-each-ref --format="%(refname)" \
+               --stdin refs/heads/extra <in 2>err &&
+       grep "unknown arguments supplied with --stdin" err
+'
+
+test_expect_success 'git for-each-ref --stdin: matches' '
+       cat >in <<-EOF &&
+       refs/tags/multi*
+       refs/heads/amb*
+       EOF
+
+       cat >expect <<-EOF &&
+       refs/heads/ambiguous
+       refs/tags/multi-ref1-100000-user1
+       refs/tags/multi-ref1-100000-user2
+       refs/tags/multi-ref1-200000-user1
+       refs/tags/multi-ref1-200000-user2
+       refs/tags/multi-ref2-100000-user1
+       refs/tags/multi-ref2-100000-user2
+       refs/tags/multi-ref2-200000-user1
+       refs/tags/multi-ref2-200000-user2
+       refs/tags/multiline
+       EOF
+
+       git for-each-ref --format="%(refname)" --stdin <in >actual &&
+       test_cmp expect actual
+'
+
 test_done