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[PATCH v5 23/34] merge-recursive: check for directory level conflicts

From
Elijah Newren <newren@gmail.com>
Date
Dec 28, 2017, 04:13 UTC
Message-ID
<20171228041352.27880-24-newren@gmail.com>
In-Reply-To
<20171228041352.27880-1-newren@gmail.com>

Before trying to apply directory renames to paths within the given directories, we want to make sure that there aren't conflicts at the directory level. There will be additional checks at the individual file level too, which will be added later.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-recursive.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
diff --git a/merge-recursive.c b/merge-recursive.c
index 6aef357e7..d92fba277 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1384,6 +1384,15 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 	return ret;
 }
 
+static int tree_has_path(struct tree *tree, const char *path)
+{
+	unsigned char hashy[20];
+	unsigned int mode_o;
+
+	return !get_tree_entry(tree->object.oid.hash, path,
+			       hashy, &mode_o);
+}
+
 static void get_renamed_dir_portion(const char *old_path, const char *new_path,
 				    char **old_dir, char **new_dir)
 {
@@ -1438,6 +1447,112 @@ static void get_renamed_dir_portion(const char *old_path, const char *new_path,
 	}
 }
 
+static void remove_hashmap_entries(struct hashmap *dir_renames,
+				   struct string_list *items_to_remove)
+{
+	int i;
+	struct dir_rename_entry *entry;
+
+	for (i = 0; i < items_to_remove->nr; i++) {
+		entry = items_to_remove->items[i].util;
+		hashmap_remove(dir_renames, entry, NULL);
+	}
+	string_list_clear(items_to_remove, 0);
+}
+
+/*
+ * There are a couple things we want to do at the directory level:
+ *   1. Check for both sides renaming to the same thing, in order to avoid
+ *      implicit renaming of files that should be left in place.  (See
+ *      testcase 6b in t6043 for details.)
+ *   2. Prune directory renames if there are still files left in the
+ *      the original directory.  These represent a partial directory rename,
+ *      i.e. a rename where only some of the files within the directory
+ *      were renamed elsewhere.  (Technically, this could be done earlier
+ *      in get_directory_renames(), except that would prevent us from
+ *      doing the previous check and thus failing testcase 6b.)
+ *   3. Check for rename/rename(1to2) conflicts (at the directory level).
+ *      In the future, we could potentially record this info as well and
+ *      omit reporting rename/rename(1to2) conflicts for each path within
+ *      the affected directories, thus cleaning up the merge output.
+ *   NOTE: We do NOT check for rename/rename(2to1) conflicts at the
+ *         directory level, because merging directories is fine.  If it
+ *         causes conflicts for files within those merged directories, then
+ *         that should be detected at the individual path level.
+ */
+static void handle_directory_level_conflicts(struct merge_options *o,
+					     struct hashmap *dir_re_head,
+					     struct tree *head,
+					     struct hashmap *dir_re_merge,
+					     struct tree *merge)
+{
+	struct hashmap_iter iter;
+	struct dir_rename_entry *head_ent;
+	struct dir_rename_entry *merge_ent;
+
+	struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
+	struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;
+
+	hashmap_iter_init(dir_re_head, &iter);
+	while ((head_ent = hashmap_iter_next(&iter))) {
+		merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
+		if (merge_ent &&
+		    !head_ent->non_unique_new_dir &&
+		    !merge_ent->non_unique_new_dir &&
+		    !strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
+			/* 1. Renamed identically; remove it from both sides */
+			string_list_append(&remove_from_head,
+					   head_ent->dir)->util = head_ent;
+			strbuf_release(&head_ent->new_dir);
+			string_list_append(&remove_from_merge,
+					   merge_ent->dir)->util = merge_ent;
+			strbuf_release(&merge_ent->new_dir);
+		} else if (tree_has_path(head, head_ent->dir)) {
+			/* 2. This wasn't a directory rename after all */
+			string_list_append(&remove_from_head,
+					   head_ent->dir)->util = head_ent;
+			strbuf_release(&head_ent->new_dir);
+		}
+	}
+
+	remove_hashmap_entries(dir_re_head, &remove_from_head);
+	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
+
+	hashmap_iter_init(dir_re_merge, &iter);
+	while ((merge_ent = hashmap_iter_next(&iter))) {
+		head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
+		if (tree_has_path(merge, merge_ent->dir)) {
+			/* 2. This wasn't a directory rename after all */
+			string_list_append(&remove_from_merge,
+					   merge_ent->dir)->util = merge_ent;
+		} else if (head_ent &&
+			   !head_ent->non_unique_new_dir &&
+			   !merge_ent->non_unique_new_dir) {
+			/* 3. rename/rename(1to2) */
+			/*
+			 * We can assume it's not rename/rename(1to1) because
+			 * that was case (1), already checked above.  So we
+			 * know that head_ent->new_dir and merge_ent->new_dir
+			 * are different strings.
+			 */
+			output(o, 1, _("CONFLICT (rename/rename): "
+				       "Rename directory %s->%s in %s. "
+				       "Rename directory %s->%s in %s"),
+			       head_ent->dir, head_ent->new_dir.buf, o->branch1,
+			       head_ent->dir, merge_ent->new_dir.buf, o->branch2);
+			string_list_append(&remove_from_head,
+					   head_ent->dir)->util = head_ent;
+			strbuf_release(&head_ent->new_dir);
+			string_list_append(&remove_from_merge,
+					   merge_ent->dir)->util = merge_ent;
+			strbuf_release(&merge_ent->new_dir);
+		}
+	}
+
+	remove_hashmap_entries(dir_re_head, &remove_from_head);
+	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
+}
+
 static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs,
 					     struct tree *tree)
 {
@@ -1869,6 +1984,10 @@ static int handle_renames(struct merge_options *o,
 	dir_re_head = get_directory_renames(head_pairs, head);
 	dir_re_merge = get_directory_renames(merge_pairs, merge);
 
+	handle_directory_level_conflicts(o,
+					 dir_re_head, head,
+					 dir_re_merge, merge);
+
 	ri->head_renames  = get_renames(o, head_pairs, head,
 					 common, head, merge, entries);
 	ri->merge_renames = get_renames(o, merge_pairs, merge,

-- 
2.15.0.408.g8e199d483
Previous: Elijah NewrenNext: Elijah Newren
Message 20 of 46 in “Add directory rename detection to git”
  1. 00/34 Add directory rename detection to gitElijah Newren, Dec 28, 2017
  2. 03/34 merge-recursive: add explanation for src_entry and dst_entryElijah Newren, Dec 28, 2017
  3. 04/34 directory rename detection: basic testcasesElijah Newren, Dec 28, 2017
  4. SZEDER GáborJan 3, 2018
  5. Elijah NewrenJan 3, 2018
  6. 07/34 directory rename detection: partially renamed directory testcase/discussionElijah Newren, Dec 28, 2017
  7. 08/34 directory rename detection: files/directories in the way of some renamesElijah Newren, Dec 28, 2017
  8. 14/34 directory rename detection: tests for handling overwriting dirty filesElijah Newren, Dec 28, 2017
  9. 10/34 directory rename detection: more involved edge/corner testcasesElijah Newren, Dec 28, 2017
  10. 11/34 directory rename detection: testcases exploring possibly suboptimal mergesElijah Newren, Dec 28, 2017
  11. 19/34 merge-recursive: split out code for determining diff_filepairsElijah Newren, Dec 28, 2017
  12. 22/34 merge-recursive: add get_directory_renames()Elijah Newren, Dec 28, 2017
  13. 28/34 merge-recursive: apply necessary modifications for directory renamesElijah Newren, Dec 28, 2017
  14. 29/34 merge-recursive: avoid clobbering untracked files with directory renamesElijah Newren, Dec 28, 2017
  15. 32/34 directory rename detection: new testcases showcasing a pair of bugsElijah Newren, Dec 28, 2017
  16. 30/34 merge-recursive: fix overwriting dirty files involved in renamesElijah Newren, Dec 28, 2017
  17. 31/34 merge-recursive: fix remaining directory rename + dirty overwrite casesElijah Newren, Dec 28, 2017
  18. 34/34 merge-recursive: ensure we write updates for directory-renamed fileElijah Newren, Dec 28, 2017
  19. 33/34 merge-recursive: avoid spurious rename/rename conflict from dir renamesElijah Newren, Dec 28, 2017
  20. 23/34 merge-recursive: check for directory level conflictsElijah Newren, Dec 28, 2017
  21. 26/34 merge-recursive: check for file level conflicts then get new nameElijah Newren, Dec 28, 2017
  22. 25/34 merge-recursive: add computation of collisions due to dir rename & mergingElijah Newren, Dec 28, 2017
  23. 21/34 merge-recursive: make a helper function for cleanup for handle_renamesElijah Newren, Dec 28, 2017
  24. 20/34 merge-recursive: add a new hashmap for storing directory renamesElijah Newren, Dec 28, 2017
  25. 24/34 merge-recursive: add a new hashmap for storing file collisionsElijah Newren, Dec 28, 2017
  26. 27/34 merge-recursive: when comparing files, don't include treesElijah Newren, Dec 28, 2017
  27. 12/34 directory rename detection: miscellaneous testcases to complete coverageElijah Newren, Dec 28, 2017
  28. 18/34 merge-recursive: make !o->detect_rename codepath more obviousElijah Newren, Dec 28, 2017
  29. 16/34 merge-recursive: introduce new functions to handle rename logicElijah Newren, Dec 28, 2017
  30. 17/34 merge-recursive: fix leaks of allocated renames and diff_filepairsElijah Newren, Dec 28, 2017
  31. 13/34 directory rename detection: tests for handling overwriting untracked filesElijah Newren, Dec 28, 2017
  32. SZEDER GáborJan 4, 2018
  33. Elijah NewrenJan 4, 2018
  34. SZEDER GáborJan 5, 2018
  35. Thomas GummererJan 5, 2018
  36. Elijah NewrenJan 5, 2018
  37. 15/34 merge-recursive: move the get_renames() functionElijah Newren, Dec 28, 2017
  38. 09/34 directory rename detection: testcases checking which side did the renameElijah Newren, Dec 28, 2017
  39. 02/34 merge-recursive: fix logic ordering issueElijah Newren, Dec 28, 2017
  40. 06/34 directory rename detection: testcases to avoid taking detection too farElijah Newren, Dec 28, 2017
  41. 01/34 Tighten and correct a few testcases for merging and cherry-pickingElijah Newren, Dec 28, 2017
  42. 05/34 directory rename detection: directory splitting testcasesElijah Newren, Dec 28, 2017
  43. Elijah NewrenJan 3, 2018
  44. Johannes SixtJan 3, 2018
  45. Elijah NewrenJan 3, 2018
  46. Johannes SixtJan 3, 2018

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