[SVN-4847] Automatic merge gets confused if merges are performed in parallel

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: all
• Component/s: libsvn_client
• Assignee: Unassigned
• Reporter: Stefan Sperling
• Created: 08/Feb/20 09:08
• Updated: 08/Feb/20 09:13

Description

The automatic merge heuristic will pick the wrong merge strategy if merges and commits are interleaved like this:

1. Create trunk and branch1
2. Commit an edit to file mu in trunk
3. Commit an edit to file iota in branch1
4. Merge trunk -> branch1
5. Merge branch1 -> trunk
6. Commit trunk
7. Commit branch1
8. Commit further edits to mu in trunk
9. Attempt to merge trunk into branch

At step 9 Subversion performs a reintegrate merge which results in a spurious merge conflict. If a sync merge is forced instead the merge completes without conflicts. If there was a way to extend the heuristic to detect this case the
merge conflict could be avoided.

This problem was reported by Daniel Dickison and discussed in detail in the users@ list thread: "False conflict with interleaved merge commits":

https://svn.haxx.se/users/archive-2020-02/0002.shtml
https://svn.haxx.se/users/archive-2020-02/0004.shtml
https://svn.haxx.se/users/archive-2020-02/0006.shtml
https://svn.haxx.se/users/archive-2020-02/0007.shtml