completion: complete 'submodule.*' config variables

In the Bash completion script, function
__git_complete_config_variable_name completes config variables and has
special logic to deal with config variables involving user-defined
names, like branch.<name>.* and remote.<name>.*.

This special logic is missing for submodule-related config variables.
Add the appropriate branches to the case statement, making use of the
in-tree '.gitmodules' to list relevant submodules.

Add corresponding tests in t9902-completion.sh, making sure we complete
both first level submodule config variables as well as second level
variables involving submodule names.

Signed-off-by: Philippe Blain <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: phil-blain

contrib/completion/git-completion.bash

@@ -2803,6 +2803,19 @@ __git_complete_config_variable_name ()
 		__gitcomp_nl_append "pushDefault" "$pfx" "$cur_" "${sfx:- }"
 		return
 		;;
+	submodule.*.*)
+		local pfx="${cur_%.*}."
+		cur_="${cur_##*.}"
+		__gitcomp "url update branch fetchRecurseSubmodules ignore active" "$pfx" "$cur_" "$sfx"
+		return
+		;;
+	submodule.*)
+		local pfx="${cur_%.*}."
+		cur_="${cur_#*.}"
+		__gitcomp_nl "$(__git config -f "$(__git rev-parse --show-toplevel)/.gitmodules" --get-regexp 'submodule.*.path' | awk -F. '{print $2}')" "$pfx" "$cur_" "."
+		__gitcomp_nl_append $'alternateErrorStrategy\nfetchJobs\nactive\nalternateLocation\nrecurse\npropagateBranches' "$pfx" "$cur_" "${sfx:- }"
+		return
+		;;
 	url.*.*)
 		local pfx="${cur_%.*}."
 		cur_="${cur_##*.}"

t/t9902-completion.sh

@@ -2583,6 +2583,35 @@ test_expect_success 'git config - variable name include' '
 	EOF
 '
 
+test_expect_success 'setup for git config submodule tests' '
+	test_create_repo sub &&
+	test_commit -C sub initial &&
+	git submodule add ./sub
+'
+
+test_expect_success 'git config - variable name - submodule' '
+	test_completion "git config submodule." <<-\EOF
+	submodule.active Z
+	submodule.alternateErrorStrategy Z
+	submodule.alternateLocation Z
+	submodule.fetchJobs Z
+	submodule.propagateBranches Z
+	submodule.recurse Z
+	submodule.sub.Z
+	EOF
+'
+
+test_expect_success 'git config - variable name - submodule names' '
+	test_completion "git config submodule.sub." <<-\EOF
+	submodule.sub.url Z
+	submodule.sub.update Z
+	submodule.sub.branch Z
+	submodule.sub.fetchRecurseSubmodules Z
+	submodule.sub.ignore Z
+	submodule.sub.active Z
+	EOF
+'
+
 test_expect_success 'git config - value' '
 	test_completion "git config color.pager " <<-\EOF
 	false Z