[PATCH v3 3/3] sparse-checkout: limit tab completion to a single level

["Lessley Dennington via GitGitGadget" <gitgitgadget@gmail.com>]

From: Lessley Dennington <lessleydennington@gmail.com>

Ensure only directories at the current level will be tab-completed with
the sparse-checkout command. For example, if paths a/b/c/ and a/d/ exist
in the current directory, running a/<TAB> will result in:

        a/b/
        a/d/

The 'sparse-checkout completes directory names' test has also been
updated/extended according to these changes.

Co-authored-by: Elijah Newren <newren@gmail.com>
Co-authored-by: Lessley Dennington <lessleydennington@gmail.com>
Signed-off-by: Lessley Dennington <lessleydennington@gmail.com>
---
 contrib/completion/git-completion.bash | 34 ++++++++++++++++++++++++--
 t/t9902-completion.sh                  | 29 ++++++++++++++--------
 2 files changed, 51 insertions(+), 12 deletions(-)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index f478883f51c..21875d08d03 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -2986,6 +2986,36 @@ _git_show_branch ()
 	__git_complete_revlist
 }
 
+__gitcomp_directories ()
+{
+     local _tmp_dir _tmp_completions
+
+     # Get the directory of the current token; this differs from dirname
+     # in that it keeps up to the final trailing slash.  If no slash found
+     # that's fine too.
+     [[ "$cur" =~ .*/ ]]
+     _tmp_dir=$BASH_REMATCH
+
+     # Find possible directory completions, adding trailing '/' characters
+     _tmp_completions="$(git ls-tree -d --name-only HEAD $_tmp_dir |
+         sed -e s%$%/%)"
+
+     if [[ -n "$_tmp_completions" ]]; then
+         # There were some directory completions, so find ones that
+         # start with "$cur", the current token, and put those in COMPREPLY
+         local i=0 c IFS=$' \t\n'
+         for c in $_tmp_completions; do
+             if [[ $c == "$cur"* ]]; then
+                 COMPREPLY+=("$c")
+             fi
+         done
+     elif [[ "$cur" =~ /$ ]]; then
+         # No possible further completions any deeper, so assume we're at
+         # a leaf directory and just consider it complete
+         __gitcomp_direct_append "$cur "
+     fi
+}
+
 __git_sparse_checkout_subcommand_opts="--cone --no-cone --sparse-index --no-sparse-index"
 
 _git_sparse_checkout ()
@@ -3007,11 +3037,11 @@ _git_sparse_checkout ()
 	case "$subcommand" in
 		set)
 			__gitcomp "$__git_sparse_checkout_subcommand_opts --stdin"
-			__gitcomp "$(git ls-tree -d -r HEAD --name-only)"
+			__gitcomp_directories
 			;;
 		add)
 			__gitcomp "--stdin"
-			__gitcomp "$(git ls-tree -d -r HEAD --name-only)"
+			__gitcomp_directories
 			;;
 		init|reapply)
 			__gitcomp "$__git_sparse_checkout_subcommand_opts"
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 4dc93ee0595..e11ff0c2efe 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -1513,21 +1513,30 @@ test_expect_success 'sparse-checkout completes directory names' '
 	(
 		cd sparse-checkout &&
 		test_completion "git sparse-checkout set f" <<-\EOF
-		folder1 Z
-		folder1/0 Z
-		folder1/0/1 Z
-		folder2 Z
-		folder2/0 Z
-		folder3 Z
+		folder1/
+		folder2/
+		folder3/
+		EOF
+	) &&
+
+	(
+		cd sparse-checkout &&
+		test_completion "git sparse-checkout set folder1/" <<-\EOF
+		folder1/0/
+		EOF
+	) &&
+
+	(
+		cd sparse-checkout &&
+		test_completion "git sparse-checkout set folder1/0/" <<-\EOF
+		folder1/0/1/
 		EOF
 	) &&
 
 	(
 		cd sparse-checkout/folder1 &&
-		test_completion "git sparse-checkout add " <<-\EOF
-		./ Z
-		0 Z
-		0/1 Z
+		test_completion "git sparse-checkout add 0" <<-\EOF
+		0/
 		EOF
 	)
 '
-- 
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