checkout-index: add --sparse option

Change the default behavior of `checkout-index --all` for sparse checkouts
to no longer refresh files outside the sparse checkout definition. The
newly-added `--sparse` option, when used with `--all`, maintains the "old"
behavior and checks out files outside the sparse checkout definition.

Signed-off-by: Victoria Dye <vdye@github.com>

Documentation/git-checkout-index.txt

@@ -12,6 +12,7 @@ SYNOPSIS
 'git checkout-index' [-u] [-q] [-a] [-f] [-n] [--prefix=<string>]
 		   [--stage=<number>|all]
 		   [--temp]
+		   [--sparse]
 		   [-z] [--stdin]
 		   [--] [<file>...]
 
@@ -37,8 +38,9 @@ OPTIONS
 
 -a::
 --all::
-	checks out all files in the index.  Cannot be used
-	together with explicit filenames.
+	checks out all files in the index, excluding those outside
+	any specified sparse checkout patterns (see `--sparse`).
+	Cannot be used together with explicit filenames.
 
 -n::
 --no-create::
@@ -59,6 +61,10 @@ OPTIONS
 	write the content to temporary files.  The temporary name
 	associations will be written to stdout.
 
+--sparse::
+	Refresh files outside of the sparse checkout boundary. May
+	only be used in conjunction with `--all`.
+
 --stdin::
 	Instead of taking list of paths from the command line,
 	read list of paths from the standard input.  Paths are

builtin/checkout-index.c

@@ -7,6 +7,7 @@
 #define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "builtin.h"
 #include "config.h"
+#include "dir.h"
 #include "lockfile.h"
 #include "quote.h"
 #include "cache-tree.h"
@@ -116,7 +117,7 @@ static int checkout_file(const char *name, const char *prefix)
 	return -1;
 }
 
-static int checkout_all(const char *prefix, int prefix_length)
+static int checkout_all(const char *prefix, int prefix_length, int include_sparse)
 {
 	int i, errs = 0;
 	struct cache_entry *last_ce = NULL;
@@ -125,6 +126,8 @@ static int checkout_all(const char *prefix, int prefix_length)
 	ensure_full_index(&the_index);
 	for (i = 0; i < active_nr ; i++) {
 		struct cache_entry *ce = active_cache[i];
+		if (!include_sparse && !path_in_sparse_checkout(ce->name, &the_index))
+			continue;
 		if (ce_stage(ce) != checkout_stage
 		    && (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
 			continue;
@@ -176,6 +179,7 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 	int i;
 	struct lock_file lock_file = LOCK_INIT;
 	int all = 0;
+	int include_sparse = 0;
 	int read_from_stdin = 0;
 	int prefix_length;
 	int force = 0, quiet = 0, not_new = 0;
@@ -185,6 +189,8 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 	struct option builtin_checkout_index_options[] = {
 		OPT_BOOL('a', "all", &all,
 			N_("check out all files in the index")),
+		OPT_BOOL(0, "sparse", &include_sparse,
+			N_("do not skip files outside the sparse checkout boundary")),
 		OPT__FORCE(&force, N_("force overwrite of existing files"), 0),
 		OPT__QUIET(&quiet,
 			N_("no warning for existing files and files not in index")),
@@ -247,6 +253,8 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 
 		if (all)
 			die("git checkout-index: don't mix '--all' and explicit filenames");
+		if (include_sparse)
+			die("git checkout-index: don't mix '--sparse' and explicit filenames");
 		if (read_from_stdin)
 			die("git checkout-index: don't mix '--stdin' and explicit filenames");
 		p = prefix_path(prefix, prefix_length, arg);
@@ -280,7 +288,7 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 	}
 
 	if (all)
-		err |= checkout_all(prefix, prefix_length);
+		err |= checkout_all(prefix, prefix_length, include_sparse);
 
 	if (pc_workers > 1)
 		err |= run_parallel_checkout(&state, pc_workers, pc_threshold,

builtin/stash.c

@@ -365,7 +365,7 @@ static int restore_untracked(struct object_id *u_tree)
 
 	child_process_init(&cp);
 	cp.git_cmd = 1;
-	strvec_pushl(&cp.args, "checkout-index", "--all", NULL);
+	strvec_pushl(&cp.args, "checkout-index", "--all", "--sparse", NULL);
 	strvec_pushf(&cp.env_array, "GIT_INDEX_FILE=%s",
 		     stash_index_path.buf);
 

t/t1092-sparse-checkout-compatibility.sh

@@ -1093,14 +1093,14 @@ test_expect_success 'checkout-index with folders' '
 	test_all_match test_must_fail git checkout-index -f -- folder1/
 '
 
-# NEEDSWORK: even in sparse checkouts, checkout-index --all will create all
-# files (even those outside the sparse definition) on disk. However, these files
-# don't appear in the percentage of tracked files in git status.
-test_expect_failure 'checkout-index --all' '
+test_expect_success 'checkout-index --all' '
 	init_repos &&
 
 	test_all_match git checkout-index --all &&
-	test_sparse_match test_path_is_missing folder1
+	test_sparse_match test_path_is_missing folder1 &&
+
+	test_all_match git checkout-index --sparse --all &&
+	test_all_match test_path_exists folder1
 '
 
 test_expect_success 'clean' '