Add a GIT_COMPLETION_SHOW_ALL_COMMANDS=1 configuration setting to go
with the existing GIT_COMPLETION_SHOW_ALL=1 added in
c099f579b98 (completion: add GIT_COMPLETION_SHOW_ALL env var,
2020-08-19).

This will include plumbing commands such as "cat-file" in "git <TAB>"
and "git c<TAB>" completion. Without/with this I have 134 and 243
completion with git <TAB>, respectively.

It was already possible to do this by tweaking
GIT_COMPLETION_SHOW_ALL_COMMANDS from the outside, that testing
variable was added in 84a97131065 (completion: let git provide the
completable command list, 2018-05-20). Doing this before loading
git-completion.bash worked:

    export GIT_TESTING_PORCELAIN_COMMAND_LIST="$(git --list-cmds=builtins,main,list-mainporcelain,others,nohelpers,alias,list-complete,config)"

But such testing variables are not meant to be used from the outside,
and we make no guarantees that those internal won't change. So let's
expose this as a dedicated configuration knob.

1. https://lore.kernel.org/git/CAGP6POJ9gwp+t-eP3TPkivBLLbNb2+qj=61Mehcj=1BgrVOSLA@mail.gmail.com/ (local)

Reported-by: Hongyi Zhao <redacted>
Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---

n Sat, Jan 22 2022, Hongyi Zhao wrote:

On Ubuntu 20.04.3 LTS, I use the following git version installed from
its apt repository:

$ git --version
git version 2.25.1

I find that there are some  sub-commands can't be completed by TAB key
[...]

Others have explained why this happens, but as noted above an easy but
undocumented workaround for this that I use, because I'd like
e.g. "cat-file" to show up in this completion. In your ~/.bashrc or
equivalent do something like this before it loads git-completion.bash:

    export GIT_TESTING_PORCELAIN_COMMAND_LIST="$(git --list-cmds=builtins,main,others,alias)"

But it would be even nicer to turn that into a first-class feature,
this patch does so. With this you can just do:

    export GIT_COMPLETION_SHOW_ALL_COMMANDS=1

 contrib/completion/git-completion.bash | 13 ++++++++++++-
 t/t9902-completion.sh                  | 27 ++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 377d6c5494a..2436b8eb6b9 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash

@@ -49,6 +49,11 @@
 #     and git-switch completion (e.g., completing "foo" when "origin/foo"
 #     exists).
 #
+#   GIT_COMPLETION_SHOW_ALL_COMMANDS
+#
+#     When set to "1" suggest all commands, including plumbing commands
+#     which are hidden by default (e.g. "cat-file" on "git ca<TAB>").
+#
 #   GIT_COMPLETION_SHOW_ALL
 #
 #     When set to "1" suggest all options, including options which are

@@ -3455,7 +3460,13 @@ __git_main ()
 			then
 				__gitcomp "$GIT_TESTING_PORCELAIN_COMMAND_LIST"
 			else
-				__gitcomp "$(__git --list-cmds=list-mainporcelain,others,nohelpers,alias,list-complete,config)"
+				local list_cmds=list-mainporcelain,others,nohelpers,alias,list-complete,config
+
+				if test "${GIT_COMPLETION_SHOW_ALL_COMMANDS-}" = "1"
+				then
+					list_cmds=builtins,$list_cmds
+				fi
+				__gitcomp "$(__git --list-cmds=$list_cmds)"
 			fi
 			;;
 		esac

diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 98c62806328..e3ea6a41b00 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh

@@ -2432,6 +2432,33 @@ test_expect_success 'option aliases are shown with GIT_COMPLETION_SHOW_ALL' '
 	EOF
 '
 
+test_expect_success 'plumbing commands are excluded without GIT_COMPLETION_SHOW_ALL_COMMANDS' '
+	. "$GIT_BUILD_DIR/contrib/completion/git-completion.bash" &&
+	sane_unset GIT_TESTING_PORCELAIN_COMMAND_LIST &&
+
+	# Just mainporcelain, not plumbing commands
+	run_completion "git c" &&
+	grep checkout out &&
+	! grep cat-file out
+'
+
+test_expect_success 'all commands are shown with GIT_COMPLETION_SHOW_ALL_COMMANDS (also main non-builtin)' '
+	. "$GIT_BUILD_DIR/contrib/completion/git-completion.bash" &&
+	GIT_COMPLETION_SHOW_ALL_COMMANDS=1 &&
+	export GIT_COMPLETION_SHOW_ALL_COMMANDS &&
+	sane_unset GIT_TESTING_PORCELAIN_COMMAND_LIST &&
+
+	# Both mainporcelain and plumbing commands
+	run_completion "git c" &&
+	grep checkout out &&
+	grep cat-file out &&
+
+	# Check "gitk", a "main" command, but not a built-in + more plumbing
+	run_completion "git g" &&
+	grep gitk out &&
+	grep get-tar-commit-id out
+'
+
 test_expect_success '__git_complete' '
 	unset -f __git_wrap__git_main &&
 

-- 
2.35.0.rc2.886.ga87834885e8