From 7d3b6308fc2e44e8ae462d56fb2f1aa61012fb35 Mon Sep 17 00:00:00 2001 From: Ivan Frade Date: Tue, 17 Mar 2020 22:29:59 -0700 Subject: [PATCH] ResolveMerger: Ignore merge conflicts if asked so The recursive merge strategy builds a virtual ancestor merging recursively the common bases (when more than one) between the want-to-merge commits. While building this virtual ancestor, content conflicts are ignored, but current code doesn't do so when a file is removed. This was spotted in [1], for example. Merging two commits to build the virtual ancestor bumped into a conflict (modified in one side, deleted in the other) that stopped the process. Follow the "spec" and in case of conflict leave the unmerged content in the index and working trees. [1] https://android-review.googlesource.com/c/kernel/common/+/1228962 Change-Id: Ife9c32ae3ac3a87d3660fa1242e07854b65169d5 Signed-off-by: Ivan Frade --- .../org/eclipse/jgit/merge/MergerTest.java | 88 +++++++++++++++++++ .../org/eclipse/jgit/merge/ResolveMerger.java | 42 +++++---- 2 files changed, 114 insertions(+), 16 deletions(-) diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/MergerTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/MergerTest.java index 032349d5f8..7a244e1d8b 100644 --- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/MergerTest.java +++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/MergerTest.java @@ -1254,6 +1254,94 @@ public class MergerTest extends RepositoryTestCase { } } + /** + * Merging two commits with a conflict in the virtual ancestor. + * + * Content conflicts while merging the virtual ancestor must be ignored. + * + * In the following tree, while merging A and B, the recursive algorithm + * finds as base commits X and Y and tries to merge them: X deletes file "a" + * and Y modifies it. + * + * Note: we delete "a" in (master) and (second-branch) to make avoid manual + * merges. The situation is the same without those deletions and fixing + * manually the merge of (merge-both-sides) on both branches. + * + * 
+	 * A  (second-branch) Merge branch 'merge-both-sides' into second-branch
+	 * |\
+	 * o | Delete modified a
+	 * | |
+	 * | | B (master) Merge branch 'merge-both-sides' (into master)
+	 * | |/|
+	 * | X | (merge-both-sides) Delete original a
+	 * | | |
+	 * | | o Delete modified a
+	 * | |/
+	 * |/|
+	 * Y | Modify a
+	 * |/
+	 * o Initial commit
+	 *
+ * + * @param strategy + * @throws Exception + */ + @Theory + public void checkMergeConflictInVirtualAncestor( + MergeStrategy strategy) throws Exception { + if (!strategy.equals(MergeStrategy.RECURSIVE)) { + return; + } + + Git git = Git.wrap(db); + + // master + writeTrashFile("a", "aaaaaaaa"); + writeTrashFile("b", "bbbbbbbb"); + git.add().addFilepattern("a").addFilepattern("b").call(); + RevCommit first = git.commit().setMessage("Initial commit").call(); + + writeTrashFile("a", "aaaaaaaaaaaaaaa"); + git.add().addFilepattern("a").call(); + RevCommit commitY = git.commit().setMessage("Modify a").call(); + + git.rm().addFilepattern("a").call(); + // Do more in this commits, so it is not identical to the deletion in + // second-branch + writeTrashFile("c", "cccccccc"); + git.add().addFilepattern("c").call(); + git.commit().setMessage("Delete modified a").call(); + + // merge-both-sides: starts before "a" is modified and deletes it + git.checkout().setCreateBranch(true).setStartPoint(first) + .setName("merge-both-sides").call(); + git.rm().addFilepattern("a").call(); + RevCommit commitX = git.commit().setMessage("Delete original a").call(); + + // second branch + git.checkout().setCreateBranch(true).setStartPoint(commitY) + .setName("second-branch").call(); + git.rm().addFilepattern("a").call(); + git.commit().setMessage("Delete modified a").call(); + + // Merge merge-both-sides into second-branch + MergeResult mergeResult = git.merge().include(commitX) + .setStrategy(strategy) + .call(); + ObjectId commitB = mergeResult.getNewHead(); + + // Merge merge-both-sides into master + git.checkout().setName("master").call(); + mergeResult = git.merge().include(commitX).setStrategy(strategy) + .call(); + + // Now, merge commit A and B (i.e. "master" and "second-branch"). + // None of them have the file "a", so there is no conflict, BUT while + // building the virtual ancestor it will find a conflict between Y and X + git.merge().include(commitB).call(); + } + private void writeSubmodule(String path, ObjectId commit) throws IOException, ConfigInvalidException { addSubmoduleToIndex(path, commit); diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java b/org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java index 575e7bd285..506d333120 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/merge/ResolveMerger.java @@ -789,27 +789,37 @@ public class ResolveMerger extends ThreeWayMerger { MergeResult result = contentMerge(base, ours, theirs, attributes); - add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0); - add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0); - DirCacheEntry e = add(tw.getRawPath(), theirs, - DirCacheEntry.STAGE_3, EPOCH, 0); + if (ignoreConflicts) { + // In case a conflict is detected the working tree file is + // again filled with new content (containing conflict + // markers). But also stage 0 of the index is filled with + // that content. + result.setContainsConflicts(false); + updateIndex(base, ours, theirs, result, attributes); + } else { + add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, EPOCH, 0); + add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, EPOCH, 0); + DirCacheEntry e = add(tw.getRawPath(), theirs, + DirCacheEntry.STAGE_3, EPOCH, 0); - // OURS was deleted checkout THEIRS - if (modeO == 0) { - // Check worktree before checking out THEIRS - if (isWorktreeDirty(work, ourDce)) - return false; - if (nonTree(modeT)) { - if (e != null) { - addToCheckout(tw.getPathString(), e, attributes); + // OURS was deleted checkout THEIRS + if (modeO == 0) { + // Check worktree before checking out THEIRS + if (isWorktreeDirty(work, ourDce)) { + return false; + } + if (nonTree(modeT)) { + if (e != null) { + addToCheckout(tw.getPathString(), e, attributes); + } } } - } - unmergedPaths.add(tw.getPathString()); + unmergedPaths.add(tw.getPathString()); - // generate a MergeResult for the deleted file - mergeResults.put(tw.getPathString(), result); + // generate a MergeResult for the deleted file + mergeResults.put(tw.getPathString(), result); + } } } return true; -- 2.39.5