On Sun, Mar 15, 2020 at 9:19 AM Derrick Stolee [off-list ref] wrote:

On 3/14/2020 3:11 AM, Elijah Newren via GitGitGadget wrote:

quoted

From: Elijah Newren <redacted>

Remove the equivalent of 'git read-tree -mu HEAD' in the sparse-checkout
codepaths for setting the SKIP_WORKTREE bits and instead use the new
update_sparsity() function.

Signed-off-by: Elijah Newren <redacted>
---
 builtin/sparse-checkout.c          | 39 +++++++-----------------------
 t/t1091-sparse-checkout-builtin.sh | 32 +++++++++++++++++-------
 2 files changed, 32 insertions(+), 39 deletions(-)

diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 740da4b6d54..5d3ec2e6be9 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c

@@ -97,47 +97,32 @@ static int update_working_directory(struct pattern_list *pl)
      int result = 0;
      struct unpack_trees_options o;
      struct lock_file lock_file = LOCK_INIT;
-     struct object_id oid;
-     struct tree *tree;
-     struct tree_desc t;
      struct repository *r = the_repository;

-     if (repo_read_index_unmerged(r))
-             die(_("you need to resolve your current index first"));
-
-     if (get_oid("HEAD", &oid))
-             return 0;
-
-     tree = parse_tree_indirect(&oid);
-     parse_tree(tree);
-     init_tree_desc(&t, tree->buffer, tree->size);
-
      memset(&o, 0, sizeof(o));
      o.verbose_update = isatty(2);
-     o.merge = 1;
      o.update = 1;
-     o.fn = oneway_merge;

I'm glad this is getting much simpler.

quoted

      o.head_idx = -1;
      o.src_index = r->index;
      o.dst_index = r->index;
      o.skip_sparse_checkout = 0;
      o.pl = pl;
-     o.keep_pattern_list = !!pl;

I'm making a mental note to see if this is necessary or not. I'm
guessing that update_sparsity() expects a pattern list as input and
will never free it, so this option is useless.

Yes, although your comment made me realize that I've got a memory leak
if we pass o->pl==NULL to update_sparsity(), which happens whenever we
pass NULL to update_working_directory().  I should fix that.

quoted

-     resolve_undo_clear_index(r->index);
      setup_work_tree();

-     cache_tree_free(&r->index->cache_tree);
-
      repo_hold_locked_index(r, &lock_file, LOCK_DIE_ON_ERROR);

-     core_apply_sparse_checkout = 1;
-     result = unpack_trees(1, &t, &o);
+     result = update_sparsity(&o);

-     if (!result) {
-             prime_cache_tree(r, r->index, tree);
+     if (result == 1)

I wonder if it is appropriate to return an enum in update_sparsity()
so this statement is clearer out-of-context. For example, I'm looking
at this patch before looking closely at the update_sparsity() patch
so I know how it will be used before I check its implementation.

Yes, that'd be better.

quoted

+             /*
+              * We don't do any special handling of warnings from untracked
+              * files in the way or dirty entries that can't be removed.
+              */
+             result = 0;
+     if (!result)
              write_locked_index(r->index, &lock_file, COMMIT_LOCK);
-     } else
+     else
              rollback_lock_file(&lock_file);

      return result;

@@ -304,8 +289,6 @@ static int sparse_checkout_init(int argc, const char **argv)
      };

      repo_read_index(the_repository);
-     require_clean_work_tree(the_repository,
-                             N_("initialize sparse-checkout"), NULL, 1, 0);

      argc = parse_options(argc, argv, NULL,
                           builtin_sparse_checkout_init_options,

@@ -560,8 +543,6 @@ static int sparse_checkout_set(int argc, const char **argv, const char *prefix,
      };

      repo_read_index(the_repository);
-     require_clean_work_tree(the_repository,
-                             N_("set sparse-checkout patterns"), NULL, 1, 0);

      argc = parse_options(argc, argv, prefix,
                           builtin_sparse_checkout_set_options,

@@ -577,8 +558,6 @@ static int sparse_checkout_disable(int argc, const char **argv)
      struct strbuf match_all = STRBUF_INIT;

      repo_read_index(the_repository);
-     require_clean_work_tree(the_repository,
-                             N_("disable sparse-checkout"), NULL, 1, 0);

In the three hunks above, do we still need repo_read_index()?

quoted

      memset(&pl, 0, sizeof(pl));
      hashmap_init(&pl.recursive_hashmap, pl_hashmap_cmp, NULL, 0);

diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index 8607a8e6d1a..0d93d3983e0 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh

@@ -277,16 +277,23 @@ test_expect_success 'cone mode: add parent path' '
      check_files repo a deep folder1
 '

-test_expect_success 'revert to old sparse-checkout on bad update' '
+test_expect_success 'not-up-to-date does not block rest of sparsification' '
      test_when_finished git -C repo sparse-checkout disable &&
      test_when_finished git -C repo reset --hard &&
      git -C repo sparse-checkout set deep &&
+
      echo update >repo/deep/deeper2/a &&
      cp repo/.git/info/sparse-checkout expect &&
-     test_must_fail git -C repo sparse-checkout set deep/deeper1 2>err &&
-     test_i18ngrep "cannot set sparse-checkout patterns" err &&
-     test_cmp repo/.git/info/sparse-checkout expect &&
-     check_files repo/deep a deeper1 deeper2
+     test_write_lines "!/deep/*/" "/deep/deeper1/" >>expect &&
+
+     git -C repo sparse-checkout set deep/deeper1 2>err &&
+
+     test_i18ngrep "Cannot update sparse checkout" err &&
+     test_cmp expect repo/.git/info/sparse-checkout &&
+     check_files repo/deep a deeper1 deeper2 &&
+     check_files repo/deep/deeper1 a deepest &&
+     check_files repo/deep/deeper1/deepest a &&
+     check_files repo/deep/deeper2 a
 '

 test_expect_success 'revert to old sparse-checkout on empty update' '

@@ -316,12 +323,19 @@ test_expect_success '.gitignore should not warn about cone mode' '
      test_i18ngrep ! "disabling cone patterns" err
 '

-test_expect_success 'sparse-checkout (init|set|disable) fails with dirty status' '
+test_expect_success 'sparse-checkout (init|set|disable) warns with dirty status' '
      git clone repo dirty &&
      echo dirty >dirty/folder1/a &&
-     test_must_fail git -C dirty sparse-checkout init &&
-     test_must_fail git -C dirty sparse-checkout set /folder2/* /deep/deeper1/* &&
-     test_must_fail git -C dirty sparse-checkout disable &&
+
+     git -C dirty sparse-checkout init 2>err &&
+     test_i18ngrep "warning.*Cannot update sparse checkout" err &&
+
+     git -C dirty sparse-checkout set /folder2/* /deep/deeper1/* &&
+     test_i18ngrep "warning.*Cannot update sparse checkout" err &&
+
+     git -C dirty sparse-checkout disable &&
+     test_i18ngrep "warning.*Cannot update sparse checkout" err &&
+
      git -C dirty reset --hard &&
      git -C dirty sparse-checkout init &&
      git -C dirty sparse-checkout set /folder2/* /deep/deeper1/* &&

I like that the test changes here are limited to updating existing
tests. You mentioned adding more tests, which I would also like, but
those can come in a follow-up patch that is dedicated to all the fun
situations we can get into, and how we should respond.

Here are a few that I've tested manually:

1. Start: no sparse-checkout
  a. Get into rebase conflict in a directory.
  b. "git sparse-checkout init --cone"
  c. See that the file is on-disk with conflict markers.
  d. Resolve conflict and "git add"
  e. "git sparse-checkout set <dir-without-conflict>"
  f. Sparse-checkout is set as expected, file is not on disk, but still staged.
  g. "git rebase --continue" succeeds.

2. Start: sparse-checkout set to "dir1"
  a. Get into merge conflict in "dir2"
  b. Resolve conflict, "git add"
  c. "git sparse-checkout update" (available after next patch)
  d. dir1 gone, dir1/file staged.
  e. git merge --continue succeeds

Those are the really big ones to me, but I'm sure we will find others.
I'm really happy that this is working as we expect.

Thanks for taking a look.