read-tree: integrate with sparse index

Enable use of sparse index in 'git read-tree'. The integration in this patch
is limited only to usage of 'read-tree' that does not need additional
functional changes for the sparse index to behave as expected (i.e., produce
the same user-facing results as a non-sparse index sparse-checkout). To
ensure no unexpected behavior occurs, the index is explicitly expanded when:

* '--no-sparse-checkout' is specified (because it disables sparse-checkout)
* '--prefix' is specified (if the prefix is inside a sparse directory, the
  prefixed tree cannot be properly traversed)
* two or more <tree-ish> arguments are specified ('twoway_merge' and
  'threeway_merge' do not yet support merging sparse directories)

Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index c1a401971c2d4b170a69e381207c43ec38dfc85d..0a52cab77522e21550e8c9a73ca271a43b3caa52 100644 (file)
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -160,8 +160,6 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
        argc = parse_options(argc, argv, cmd_prefix, read_tree_options,
                             read_tree_usage, 0);
 
-       hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
-
        prefix_set = opts.prefix ? 1 : 0;
        if (1 < opts.merge + opts.reset + prefix_set)
                die("Which one? -m, --reset, or --prefix?");
@@ -173,6 +171,11 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
        if (opts.reset)
                opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;
 
+       prepare_repo_settings(the_repository);
+       the_repository->settings.command_requires_full_index = 0;
+
+       hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
+
        /*
         * NEEDSWORK
         *
@@ -214,6 +217,10 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
        if (opts.merge && !opts.index_only)
                setup_work_tree();
 
+       /* TODO: audit sparse index behavior in unpack_trees */
+       if (opts.skip_sparse_checkout || opts.prefix)
+               ensure_full_index(&the_index);
+
        if (opts.merge) {
                switch (stage - 1) {
                case 0:
@@ -223,11 +230,21 @@ int cmd_read_tree(int argc, const char **argv, const char *cmd_prefix)
                        opts.fn = opts.prefix ? bind_merge : oneway_merge;
                        break;
                case 2:
+                       /*
+                        * TODO: update twoway_merge to handle edit/edit conflicts in
+                        * sparse directories.
+                        */
+                       ensure_full_index(&the_index);
                        opts.fn = twoway_merge;
                        opts.initial_checkout = is_cache_unborn();
                        break;
                case 3:
                default:
+                       /*
+                        * TODO: update threeway_merge to handle edit/edit conflicts in
+                        * sparse directories.
+                        */
+                       ensure_full_index(&the_index);
                        opts.fn = threeway_merge;
                        break;
                }

diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index 9bb5aeb979c3ec38c874a550a15799bcab7e7a82..86241b01a59a923106aaad15fba5f2e404fd1a3b 100755 (executable)
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -1409,6 +1409,17 @@ test_expect_success 'sparse index is not expanded: fetch/pull' '
        ensure_not_expanded pull full base
 '
 
+test_expect_success 'sparse index is not expanded: read-tree' '
+       init_repos &&
+
+       ensure_not_expanded checkout -b test-branch update-folder1 &&
+       for MERGE_TREES in "update-folder2"
+       do
+               ensure_not_expanded read-tree -mu $MERGE_TREES &&
+               ensure_not_expanded reset --hard || return 1
+       done
+'
+
 test_expect_success 'ls-files' '
        init_repos &&