Re: [PATCH 3/3] completion: match ctags symbol names in grep patterns

Jeff King [off-list ref] writes:

A common thing to grep for is the name of a symbol. This
patch teaches the completion for "git grep" to look in
a 'tags' file, if present, to complete a pattern. For
example, in git.git:

  $ make tags
  $ git grep get_sha1<Tab><Tab>
  get_sha1                 get_sha1_oneline
  get_sha1_1               get_sha1_with_context
  get_sha1_basic           get_sha1_with_context_1
  get_sha1_hex             get_sha1_with_mode
  get_sha1_hex_segment     get_sha1_with_mode_1
  get_sha1_mb

Signed-off-by: Jeff King <redacted>
---
It's debatable whether this belongs in the generic completion code, as
it really only works if your project uses ctags. But I find it to be a
huge timesaver for finding callsites of functions, especially when
coupled with "git jump grep" from the previous patch.

Could you elaborate a bit more on how this would help for finding
callsites? You are looking at a function and do not want to break its
callers, so at that point presumably you already know the name of the
function, no?

Ahh, Ok, you do not necessarily want to type the long function name.

By the way, I notice that "make tags" runs "find ." looking for any files
and directories that match "*.[hcS]" (so do $(ETAGS_TARGET) and cscope),
without even excluding .git metadirectory.

Perhaps something like this is in order?

 Makefile |   14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 17404c4..b38f55b 100644
--- a/Makefile
+++ b/Makefile

@@ -2127,17 +2127,25 @@ po/git.pot: $(LOCALIZED_C)
 
 pot: po/git.pot
 
+git_check = $(shell git ls-files >/dev/null 2>&1; echo $$?)
+ifeq ($(git_check),0)
+FIND_SOURCE_FILES = git ls-files '*.[hcS]'
+else
+FIND_SOURCE_FILES = $(FIND) . \( -name .git -type d -prune \) \
+		-o \( -name '*.[hcS]' -type f -print \)
+endif
+
 $(ETAGS_TARGET): FORCE
 	$(RM) $(ETAGS_TARGET)
-	$(FIND) . -name '*.[hcS]' -print | xargs etags -a -o $(ETAGS_TARGET)
+	$(FIND_SOURCE_FILES) | xargs etags -a -o $(ETAGS_TARGET)
 
 tags: FORCE
 	$(RM) tags
-	$(FIND) . -name '*.[hcS]' -print | xargs ctags -a
+	$(FIND_SOURCE_FILES) | xargs ctags -a
 
 cscope:
 	$(RM) cscope*
-	$(FIND) . -name '*.[hcS]' -print | xargs cscope -b
+	$(FIND_SOURCE_FILES) | xargs cscope -b
 
 ### Detect prefix changes
 TRACK_CFLAGS = $(CC):$(subst ','\'',$(ALL_CFLAGS)):\

Junio C Hamano wrote:

Perhaps something like this is in order?

[...]

Neat.  I'd prefer something like

	FIND_SOURCE_FILES = \
		git ls-files '*.[hcS]' 2>/dev/null || \
		$(FIND) . -name .git -prune -o -name '*.[hcS]' -type f -print

that avoid punishing people who were using the makefile for some
purpose unrelated to tags and cscope, though. ;)

On Tue, Oct 18, 2011 at 12:15:23AM -0700, Junio C Hamano wrote:

quoted

It's debatable whether this belongs in the generic completion code, as
it really only works if your project uses ctags. But I find it to be a
huge timesaver for finding callsites of functions, especially when
coupled with "git jump grep" from the previous patch.

Could you elaborate a bit more on how this would help for finding
callsites? You are looking at a function and do not want to break its
callers, so at that point presumably you already know the name of the
function, no?

Ahh, Ok, you do not necessarily want to type the long function name.

Exactly. Actually, it is often not so much "do not want to type" as
"cannot remember the exact name", but the effect is the same. :)

I use the same completion for "vim -t" which will jump to the
definition.

By the way, I notice that "make tags" runs "find ." looking for any files
and directories that match "*.[hcS]" (so do $(ETAGS_TARGET) and cscope),
without even excluding .git metadirectory.

Perhaps something like this is in order?
[...]
+FIND_SOURCE_FILES = git ls-files '*.[hcS]'

Makes sense to me. I doubt it matters much in practice, though, as we
don't tend to have random untracked source files lying around.

My version of ctags will actually do the recursion itself with "ctags
-R", picking out any files with with languages it knows about. But maybe
not all versions do that.

Also, I have often found myself trying to do completion on shell
functions. I wonder if it's worth adding them to the list (again, my
version of ctags understands bourne shell just fine, but I don't know if
all do).

-Peff