[PATCH 3/8] merge-ort: record the reason that we want a rename for a directory

From

Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>

Date

Mar 13, 2021, 22:22 UTC

Message-ID

<05850cb49823ea9c6d6c7cfd3b4adbbc1c47abc6.1615674128.git.gitgitgadget@gmail.com>

In-Reply-To

<pull.853.git.1615674128.gitgitgadget@gmail.com>

From: Elijah Newren <newren@gmail.com>

This sets up three different types of directories:
  * directories that had new files added to them
  * directories underneath a directory that had new files added to them
  * directories where no new files were added to it or any leading path

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 diffcore-rename.c |  2 +-
 diffcore.h        |  7 +++++++
 merge-ort.c       | 41 ++++++++++++++++++++++++++++++++++++++---
 3 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/diffcore-rename.c b/diffcore-rename.c
index 6487825317ff..fafec66b29e9 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -667,7 +667,7 @@ static void cleanup_dir_rename_info(struct dir_rename_info *info,
 		const char *source_dir = entry->key;
 		struct strintmap *counts = entry->value;
 
-		if (!strintmap_contains(dirs_removed, source_dir)) {
+		if (!strintmap_get(dirs_removed, source_dir)) {
 			string_list_append(&to_remove, source_dir);
 			strintmap_clear(counts);
 			continue;
diff --git a/diffcore.h b/diffcore.h
index 4f168b385fde..d5a497b7a162 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -161,6 +161,13 @@ struct diff_filepair *diff_queue(struct diff_queue_struct *,
 				 struct diff_filespec *);
 void diff_q(struct diff_queue_struct *, struct diff_filepair *);
 
+/* dir_rename_relevance: the reason we want rename information for a dir */
+enum dir_rename_relevance {
+	NOT_RELEVANT = 0,
+	RELEVANT_FOR_ANCESTOR = 1,
+	RELEVANT_FOR_SELF = 2
+};
+
 void partial_clear_dir_rename_count(struct strmap *dir_rename_count);
 
 void diffcore_break(struct repository *, int);
diff --git a/merge-ort.c b/merge-ort.c
index 6fa670396ce4..e2606c73ad88 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -73,6 +73,10 @@ struct rename_info {
 
 	/*
 	 * dirs_removed: directories removed on a given side of history.
+	 *
+	 * The keys of dirs_removed[side] are the directories that were removed
+	 * on the given side of history.  The value of the strintmap for each
+	 * directory is a value from enum dir_rename_relevance.
 	 */
 	struct strintmap dirs_removed[3];
 
@@ -729,10 +733,41 @@ static void collect_rename_info(struct merge_options *opt,
 	if (dirmask == 1 || dirmask == 3 || dirmask == 5) {
 		/* absent_mask = 0x07 - dirmask; sides = absent_mask/2 */
 		unsigned sides = (0x07 - dirmask)/2;
+		unsigned relevance = (renames->dir_rename_mask == 0x07) ?
+					RELEVANT_FOR_ANCESTOR : NOT_RELEVANT;
+		/*
+		 * Record relevance of this directory.  However, note that
+		 * when collect_merge_info_callback() recurses into this
+		 * directory and calls collect_rename_info() on paths
+		 * within that directory, if we find a path that was added
+		 * to this directory on the other side of history, we will
+		 * upgrade this value to RELEVANT_FOR_SELF; see below.
+		 */
 		if (sides & 1)
-			strintmap_set(&renames->dirs_removed[1], fullname, 1);
+			strintmap_set(&renames->dirs_removed[1], fullname,
+				      relevance);
 		if (sides & 2)
-			strintmap_set(&renames->dirs_removed[2], fullname, 1);
+			strintmap_set(&renames->dirs_removed[2], fullname,
+				      relevance);
+	}
+
+	/*
+	 * Here's the block that potentially upgrades to RELEVANT_FOR_SELF.
+	 * When we run across a file added to a directory.  In such a case,
+	 * find the directory of the file and upgrade its relevance.
+	 */
+	if (renames->dir_rename_mask == 0x07 &&
+	    (filemask == 2 || filemask == 4)) {
+		/*
+		 * Need directory rename for parent directory on other side
+		 * of history from added file.  Thus
+		 *    side = (~filemask & 0x06) >> 1
+		 * or
+		 *    side = 3 - (filemask/2).
+		 */
+		unsigned side = 3 - (filemask >> 1);
+		strintmap_set(&renames->dirs_removed[side], dirname,
+			      RELEVANT_FOR_SELF);
 	}
 
 	if (filemask == 0 || filemask == 7)
@@ -3446,7 +3481,7 @@ static void merge_start(struct merge_options *opt, struct merge_result *result)
 	renames = &opt->priv->renames;
 	for (i = MERGE_SIDE1; i <= MERGE_SIDE2; i++) {
 		strintmap_init_with_options(&renames->dirs_removed[i],
-					    0, NULL, 0);
+					    NOT_RELEVANT, NULL, 0);
 		strmap_init_with_options(&renames->dir_rename_count[i],
 					 NULL, 1);
 		strmap_init_with_options(&renames->dir_renames[i],

-- 
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