narrow: fix commits of empty files


narrow: fix commits of empty files

The problem is that when committing a new file with empty contents (or
in general empty file with filelog p1 = -1), hg commit with narrow
doesn't create a filelog revision at all, which causes failures in
further commands.

The problem seems to be that:

  • hg thinks that instead of creating a new filelog revision, it can use the filelog's p1 (the nullrev)
  • because it thinks the file contents is the same in that revision and in p1
  • because narrowfilelog.cmp(nullrev, b'') is True (unlike with filelog.cmp)

It's not clear to me which cmp behaves better. But I think it makes
sense to change the commit code to not to "reuse" the null rev when
adding an empty file with filelog p1 == filelog p2 == -1. This is
consistent with never writing the null rev in the manifest, which `hg
verify` claims is an invariant:

inside/c@4: manifest refers to unknown revision 000000000000

Differential Revision: https://phab.mercurial-scm.org/D11400


valentin.gatienbaronSep 10 2021, 2:57 PM
Differential Revision
D11400: narrow: fix commits of empty files
rHGcc33deae66a1: narrow: show repo corruption when commiting empty files