Re: [PATCH 8/7] grep: treat revs the same for --untracked as for --no-index

[Junio C Hamano]

Jeff King  writes:

> ...
> The rationale for doing this with --no-index is that it is
> meant to be used outside a repository, and so parsing revs
> at all does not make sense.
>
> This patch gives --untracked the same treatment. While it
> _is_ meant to be used in a repository, it is explicitly
> about grepping the non-repository contents. Telling the user
> "we found a rev, but you are not allowed to use revs" is
> not really helpful compared to "we treated your argument as
> a path, and could not find it".

Yup, both sounds very sensible.  Thanks.

[PATCH 8/7] grep: treat revs the same for --untracked as for --no-index

[Jeff King]

On Tue, Feb 14, 2017 at 10:19:56AM -0800, Jonathan Tan wrote:

> > I wasn't sure if we wanted to treat "untracked" in the same way.
> > Certainly we can catch the error here for the seen_dashdash case, but is
> > it also the case that:
> > 
> >   echo content >master
> >   git grep --untracked pattern master
> > 
> > should treat "master" as a path?
> 
> It is already the case that it cannot be treated as a rev:
> 
>   $ git grep --untracked pattern master
>   fatal: --no-index or --untracked cannot be used with revs.
> 
> So I think it would be better if it was treated as a path, for consistency
> with --no-index. I'm OK either way, though.

Right, it's always been disallowed. But the early detection changes a
few user-visible behaviors like the exact error message, and how
disambiguation works (see below). I think the arguments for making that
change for --no-index are stronger than for --untracked. But it probably
makes sense for --untracked, too.

Here's a patch on top of my series that lumps the two together again. It
_could_ be squashed into the earlier patch, but I think I prefer keeping
it separate.

-- >8 --
Subject: [PATCH] grep: treat revs the same for --untracked as for --no-index

git-grep has always disallowed grepping in a tree (as
opposed to the working directory) with both --untracked
and --no-index. But we traditionally did so by first
collecting the revs, and then complaining when any were
provided.

The --no-index option recently learned to detect revs
much earlier. This has two user-visible effects:

  - we don't bother to resolve revision names at all. So
when there's a rev/path ambiguity, we always choose to
treat it as a path.

  - likewise, when you do specify a revision without "--",
the error you get is "no such path" and not "--untracked
cannot be used with revs".

The rationale for doing this with --no-index is that it is
meant to be used outside a repository, and so parsing revs
at all does not make sense.

This patch gives --untracked the same treatment. While it
_is_ meant to be used in a repository, it is explicitly
about grepping the non-repository contents. Telling the user
"we found a rev, but you are not allowed to use revs" is
not really helpful compared to "we treated your argument as
a path, and could not find it".

Signed-off-by: Jeff King 
---
 builtin/grep.c  | 10 +-
 t/t7810-grep.sh |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/builtin/grep.c b/builtin/grep.c
index 1454bef49..9304c33e7 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -967,6 +967,7 @@ int cmd_grep(int argc, const char **argv, const char 
*prefix)
int dummy;
int use_index = 1;
int pattern_type_arg = GREP_PATTERN_TYPE_UNSPECIFIED;
+   int allow_revs;
 
struct option options[] = {
OPT_BOOL(0, "cached", ,
@@ -1165,6 +1166,7 @@ int cmd_grep(int argc, const char **argv, const char 
*prefix)
 * to it must resolve as a rev. If not, then we stop at the first
 * non-rev and assume everything else is a path.
 */
+   allow_revs = use_index && !untracked;
for (i = 0; i < argc; i++) {
const char *arg = argv[i];
unsigned char sha1[20];
@@ -1176,9 +1178,9 @@ int cmd_grep(int argc, const char **argv, const char 
*prefix)
break;
}
 
-   if (!use_index) {
+   if (!allow_revs) {
if (seen_dashdash)
-   die(_("--no-index cannot be used with revs"));
+   die(_("--no-index or --untracked cannot be used 
with revs"));
break;
}
 
@@ -1201,7 +1203,7 @@ int cmd_grep(int argc, const char **argv, const char 
*prefix)
if (!seen_dashdash) {
int j;
for (j = i; j < argc; j++)
-   verify_filename(prefix, argv[j], j == i && use_index);
+   verify_filename(prefix, argv[j], j == i && allow_revs);
}
 
parse_pathspec(, 0,
@@ -1273,8 +1275,6 @@ int cmd_grep(int argc, const char **argv, const char 
*prefix)
 
if (!use_index || untracked) {
int use_exclude = (opt_exclude < 0) ? use_index : !!opt_exclude;
-   if (list.nr)
-   die(_("--no-index or --untracked cannot be used with 
revs."));
hit = grep_directory(, , use_exclude, use_index);
} else if (0 <= opt_exclude) {
die(_("--[no-]exclude-standard cannot be used for tracked 
contents."));
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 0ff9f6cae..cee42097b 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -1032,7 +1032,7 @@ test_expect_success 'grep --no-index pattern -- path' '
 
 test_expect_success 'grep --no-index complains of revs' '
test_must_fail git grep --no-index o master -- 2>err &&
-   test_i18ngrep