Fix long-standing excessive file merges Since switching to the multihead approach, we've been creating excessive file-level merges where files are marked as merged with their ancestors. This explicitly checks at commit time whether the two parent versions are linearly related, and if so, reduces the file check-in to a non-merge. Then the file is compared against the remaining parent, and, if equal, skips check-in of that file (as it's not changed). Since we're not checking in all files that were different between versions, we no longer need to mark so many files for merge. This removes most of the 'm' state marking as well. Finally, it is possible to do a tree-level merge with no file-level changes. This will happen if one user changes file A and another changes file B. Thus, if we have have two parents, we allow commit to proceed even if there are no file-level changes.

A b
b
 b: copy a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
changeset:   1:3b5b84850bbe
tag:         tip
user:        test
date:        Thu Jan  1 00:00:00 1970 +0000
summary:     2

changeset:   0:c19d34741b0a
user:        test
date:        Thu Jan  1 00:00:00 1970 +0000
summary:     1

changeset:   0:c19d34741b0a
user:        test
date:        Thu Jan  1 00:00:00 1970 +0000
summary:     1

566e338d09a089ba737c21e0d3759980  .hg/data/b.d
60b725f10c9c85c70d97880dfe8191b3  bsum
60b725f10c9c85c70d97880dfe8191b3  asum
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
2 files, 2 changesets, 2 total revisions