[PATCH v2 16/18] unpack-trees: provide warnings on sparse updates for unmerged paths too

["Elijah Newren via GitGitGadget" <gitgitgadget@xxxxxxxxx>]

From: Elijah Newren <newren@xxxxxxxxx>

When sparse-checkout runs to update the list of sparsity patterns, it
gives warnings if it can't remove paths from the working tree because
those files have dirty changes.  Add a similar warning for unmerged
paths as well.

Signed-off-by: Elijah Newren <newren@xxxxxxxxx>
---
 t/t1091-sparse-checkout-builtin.sh | 24 ++++++++++++++++++++++++
 unpack-trees.c                     | 30 ++++++++++++++++++++++++++++++
 unpack-trees.h                     |  1 +
 3 files changed, 55 insertions(+)

diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index 11eb567f3fb..39093bcd5ec 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -342,6 +342,30 @@ test_expect_success 'sparse-checkout (init|set|disable) warns with dirty status'
 	git -C dirty sparse-checkout disable
 '
 
+test_expect_success 'sparse-checkout (init|set|disable) warns with unmerged status' '
+	git clone repo unmerged &&
+
+	cat >input <<-EOF &&
+	0 0000000000000000000000000000000000000000	folder1/a
+	100644 $(git -C unmerged rev-parse HEAD:folder1/a) 1	folder1/a
+	EOF
+	git -C unmerged update-index --index-info <input &&
+
+	git -C unmerged sparse-checkout init 2>err &&
+	test_i18ngrep "warning.*The following paths are unmerged" err &&
+
+	git -C unmerged sparse-checkout set /folder2/* /deep/deeper1/* &&
+	test_i18ngrep "warning.*The following paths are unmerged" err &&
+
+	git -C unmerged sparse-checkout disable &&
+	test_i18ngrep "warning.*The following paths are unmerged" err &&
+
+	git -C unmerged reset --hard &&
+	git -C unmerged sparse-checkout init &&
+	git -C unmerged sparse-checkout set /folder2/* /deep/deeper1/* &&
+	git -C unmerged sparse-checkout disable
+'
+
 test_expect_success 'cone mode: set with core.ignoreCase=true' '
 	rm repo/.git/info/sparse-checkout &&
 	git -C repo sparse-checkout init --cone &&
diff --git a/unpack-trees.c b/unpack-trees.c
index 7c24933016b..298241a5e0e 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -52,6 +52,9 @@ static const char *unpack_plumbing_errors[NB_UNPACK_TREES_WARNING_TYPES] = {
 	/* WARNING_SPARSE_NOT_UPTODATE_FILE */
 	"Path '%s' not uptodate; will not remove from working tree.",
 
+	/* WARNING_SPARSE_UNMERGED_FILE */
+	"Path '%s' unmerged; will not remove from working tree.",
+
 	/* WARNING_SPARSE_ORPHANED_NOT_OVERWRITTEN */
 	"Path '%s' already present; will not overwrite with sparse update.",
 };
@@ -173,6 +176,8 @@ void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
 
 	msgs[WARNING_SPARSE_NOT_UPTODATE_FILE] =
 		_("The following paths are not up to date and were left despite sparse patterns:\n%s");
+	msgs[WARNING_SPARSE_UNMERGED_FILE] =
+		_("The following paths are unmerged and were left despite sparse patterns:\n%s");
 	msgs[WARNING_SPARSE_ORPHANED_NOT_OVERWRITTEN] =
 		_("The following paths were already present and thus not updated despite sparse patterns:\n%s");
 
@@ -548,6 +553,23 @@ static int apply_sparse_checkout(struct index_state *istate,
 	return 0;
 }
 
+static int warn_conflicted_path(struct index_state *istate,
+				int i,
+				struct unpack_trees_options *o)
+{
+	char *conflicting_path = istate->cache[i]->name;
+	int count = 0;
+
+	add_rejected_path(o, WARNING_SPARSE_UNMERGED_FILE, conflicting_path);
+
+	/* Find out how many higher stage entries at same path */
+	while (++count < istate->cache_nr &&
+	       !strcmp(conflicting_path,
+		       istate->cache[i+count]->name))
+		/* do nothing */;
+	return count;
+}
+
 static inline int call_unpack_fn(const struct cache_entry * const *src,
 				 struct unpack_trees_options *o)
 {
@@ -1793,6 +1815,14 @@ enum update_sparsity_result update_sparsity(struct unpack_trees_options *o)
 	for (i = 0; i < o->src_index->cache_nr; i++) {
 		struct cache_entry *ce = o->src_index->cache[i];
 
+
+		if (ce_stage(ce)) {
+			/* -1 because for loop will increment by 1 */
+			i += warn_conflicted_path(o->src_index, i, o) - 1;
+			ret = UPDATE_SPARSITY_WARNINGS;
+			continue;
+		}
+
 		if (apply_sparse_checkout(o->src_index, ce, o))
 			ret = UPDATE_SPARSITY_WARNINGS;
 
diff --git a/unpack-trees.h b/unpack-trees.h
index d91c65ae453..f970fd6c2f4 100644
--- a/unpack-trees.h
+++ b/unpack-trees.h
@@ -27,6 +27,7 @@ enum unpack_trees_error_types {
 	NB_UNPACK_TREES_ERROR_TYPES,
 
 	WARNING_SPARSE_NOT_UPTODATE_FILE,
+	WARNING_SPARSE_UNMERGED_FILE,
 	WARNING_SPARSE_ORPHANED_NOT_OVERWRITTEN,
 
 	NB_UNPACK_TREES_WARNING_TYPES,
-- 
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