Subject: Re: [PATCH/RFC 0/2] Automate updating git-completion.bash a bit

From: Duy Nguyen <[email-masked]>
Date: Wed, 17 Jan 2018 16:34:32 +0700

Actually I forgot another option. What if we automate updating the
script at "compile" time instead of calling git at run time? E.g. with
something like below, a contributor could just run

    make update-completion

then add git-completion.bash changes to the same patch that introduces
new options. If they forget, Junio could always run this near -rc0.

I know this output is a bit ugly. I probably could try to make the
update work with wrapped __gitcomp lines to be friendlier to human
eyes.

-- 8< --
diff --git a/Makefile b/Makefile
index 1a9b23b679..05eb7c8742 100644
--- a/Makefile
+++ b/Makefile
@@ -2834,3 +2834,5 @@ cover_db: coverage-report
 cover_db_html: cover_db
 	cover -report html -outputdir cover_db_html cover_db
 
+update-completion:
+	contrib/completion/update.sh contrib/completion/git-completion.bash ./git
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 3683c772c5..e8c224f486 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1585,21 +1585,7 @@ _git_grep ()
 
 	case "$cur" in
 	--*)
-		__gitcomp "
-			--cached
-			--text --ignore-case --word-regexp --invert-match
-			--full-name --line-number
-			--extended-regexp --basic-regexp --fixed-strings
-			--perl-regexp
-			--threads
-			--files-with-matches --name-only
-			--files-without-match
-			--max-depth
-			--count
-			--and --or --not --all-match
-			--break --heading --show-function --function-context
-			--untracked --no-index
-			"
+		__gitcomp_auto grep "--cached --text --ignore-case --word-regexp --invert-match --full-name --line-number --extended-regexp --basic-regexp --fixed-strings --perl-regexp --threads --files-with-matches --name-only --files-without-match --max-depth --count --and --or --not --all-match --break --heading --show-function --function-context --untracked --no-index"
 		return
 		;;
 	esac
diff --git a/contrib/completion/update.sh b/contrib/completion/update.sh
new file mode 100755
index 0000000000..99c4841152
--- /dev/null
+++ b/contrib/completion/update.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+file="$1"
+git="$2"
+
+grep __gitcomp_auto "$file" | while read a cmd b; do
+    sed -i "s/\\(.*$a $cmd \).*/\\1$("$git" $cmd --git-completion-helper)/" "$file"
+done
-- 8< --

On Wed, Jan 17, 2018 at 04:16:22PM +0700, Duy Nguyen wrote:
> On Wed, Jan 17, 2018 at 7:51 AM, SZEDER Gábor <[email-masked]> wrote:
> > On Tue, Jan 16, 2018 at 11:36 AM, Nguyễn Thái Ngọc Duy
> > <[email-masked]> wrote:
> >> I noticed --recurse-submodules was missing from git-grep complete
> >> list. Then I found a couple more should be on the list as well and
> >> many more in future may face the same faith. Perhaps this helps remedy
> >> this situation?
> >>
> >> This lets us extract certain information from git commands and feed it
> >> directly to git-completion.bash. Now long options by default will
> >> be complete-able (which also means it's the reviewer's and coder's
> >> responsibility to add "no complete" flag appropriately) but I think
> >> the number of new dangerous options will be much fewer than
> >> completeable ones.
> >>
> >> This is not really a new idea. Python has argcomplete that does more
> >> or less the same thing.
> >
> > This has come up before for Git as well, see:
> >
> >   https://public-inbox.org/git/[email-masked]/T/#u
> 
> Thanks! I did search the archive but couldn't find this one.
> 
> >
> > I see that your approach solves one of the shortcomings of those older
> > patches, namely it makes possible to omit dangerous options from
> > completion.  Great.
> >
> > I also see that you want to invoke git in a subshell every time the user
> > attempts to complete an --option.  Not so great, at least for Windows
> > users.  That older thread contains a few ideas about how to do it only
> > once by lazy-initializing a variable for each command to hold its
> > options.
> 
> Noted.
> 
> I see you also pointed out the problem with running commands like
> "git-status" without a repository. I'll try to address this too if
> possible (I'm thinking about making struct options[] available outside
> cmd_*(); then we could handle it more like "git --version" which
> always works)
> -- 
> Duy