[PATCH v2 07/11] merge-ort: add implementation of both sides renaming differently

From: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>
Date: Dec 14, 2020, 16:21 UTC
Message-ID: <d00e26be784d7915b2d476b0c86f37aa366a4274.1607962900.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.812.v2.git.1607962900.gitgitgadget@gmail.com>

From: Elijah Newren <newren@gmail.com>

Implement rename/rename(1to2) handling, i.e. both sides of history renaming a file and rename it differently. This code replaces the following from merge-recurisve.c:

  * all the 1to2 code in process_renames()
  * the RENAME_ONE_FILE_TO_TWO case of process_entry()
  * handle_rename_rename_1to2()

Also, there is some shared code from merge-recursive.c for multiple different rename cases which we will no longer need for this case (or other rename cases):

  * handle_file_collision()
  * setup_rename_conflict_info()

The consolidation of five separate codepaths into one is made possible by a change in design: process_renames() tweaks the conflict_info entries within opt->priv->paths such that process_entry() can then handle all the non-rename conflict types (directory/file, modify/delete, etc.) orthogonally. This means we're much less likely to miss special implementation of some kind of combination of conflict types (see commits brought in by 66c62eaec6 ("Merge branch 'en/merge-tests'", 2020-11-18), especially commit ef52778708 ("merge tests: expect improved directory/file conflict handling in ort", 2020-10-26) for more details). That, together with letting worktree/index updating be handled orthogonally in the merge_switch_to_result() function, dramatically simplifies the code for various special rename cases.

To be fair, there is a _slight_ tweak to process_entry() here to make sure that the two different paths aren't marked as clean but are left in a conflicted state. So process_renames() and process_entry() aren't quite entirely orthogonal, but they are pretty close.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 merge-ort.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 3 deletions(-)

diff --git a/merge-ort.c b/merge-ort.c
index 4034ffcf501..19477cfae60 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -707,7 +707,58 @@ static int process_renames(struct merge_options *opt,
 			}
 
 			/* This is a rename/rename(1to2) */
-			die("Not yet implemented");
+			clean_merge = handle_content_merge(opt,
+							   pair->one->path,
+							   &base->stages[0],
+							   &side1->stages[1],
+							   &side2->stages[2],
+							   pathnames,
+							   1 + 2 * opt->priv->call_depth,
+							   &merged);
+			if (!clean_merge &&
+			    merged.mode == side1->stages[1].mode &&
+			    oideq(&merged.oid, &side1->stages[1].oid))
+				was_binary_blob = 1;
+			memcpy(&side1->stages[1], &merged, sizeof(merged));
+			if (was_binary_blob) {
+				/*
+				 * Getting here means we were attempting to
+				 * merge a binary blob.
+				 *
+				 * Since we can't merge binaries,
+				 * handle_content_merge() just takes one
+				 * side.  But we don't want to copy the
+				 * contents of one side to both paths.  We
+				 * used the contents of side1 above for
+				 * side1->stages, let's use the contents of
+				 * side2 for side2->stages below.
+				 */
+				oidcpy(&merged.oid, &side2->stages[2].oid);
+				merged.mode = side2->stages[2].mode;
+			}
+			memcpy(&side2->stages[2], &merged, sizeof(merged));
+
+			side1->path_conflict = 1;
+			side2->path_conflict = 1;
+			/*
+			 * TODO: For renames we normally remove the path at the
+			 * old name.  It would thus seem consistent to do the
+			 * same for rename/rename(1to2) cases, but we haven't
+			 * done so traditionally and a number of the regression
+			 * tests now encode an expectation that the file is
+			 * left there at stage 1.  If we ever decide to change
+			 * this, add the following two lines here:
+			 *    base->merged.is_null = 1;
+			 *    base->merged.clean = 1;
+			 * and remove the setting of base->path_conflict to 1.
+			 */
+			base->path_conflict = 1;
+			path_msg(opt, oldpath, 0,
+				 _("CONFLICT (rename/rename): %s renamed to "
+				   "%s in %s and to %s in %s."),
+				 pathnames[0],
+				 pathnames[1], opt->branch1,
+				 pathnames[2], opt->branch2);
 
 			i++; /* We handled both renames, i.e. i+1 handled */
 			continue;
@@ -1292,13 +1343,13 @@ static void process_entry(struct merge_options *opt,
 		int side = (ci->filemask == 4) ? 2 : 1;
 		ci->merged.result.mode = ci->stages[side].mode;
 		oidcpy(&ci->merged.result.oid, &ci->stages[side].oid);
-		ci->merged.clean = !ci->df_conflict;
+		ci->merged.clean = !ci->df_conflict && !ci->path_conflict;
 	} else if (ci->filemask == 1) {
 		/* Deleted on both sides */
 		ci->merged.is_null = 1;
 		ci->merged.result.mode = 0;
 		oidcpy(&ci->merged.result.oid, &null_oid);
-		ci->merged.clean = 1;
+		ci->merged.clean = !ci->path_conflict;
 	}
 
 	/*

-- 
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