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
--- a/mercurial/commit.py Fri Sep 10 14:37:03 2021 -0400
+++ b/mercurial/commit.py Fri Sep 10 14:57:00 2021 -0400
@@ -389,6 +389,7 @@
text = fctx.data()
if (
fparent2 != repo.nullid
+ or fparent1 == repo.nullid
or meta
or flog.cmp(fparent1, text)
or force_new_node
--- a/tests/test-narrow-commit.t Fri Sep 10 14:37:03 2021 -0400
+++ b/tests/test-narrow-commit.t Fri Sep 10 14:57:00 2021 -0400
@@ -105,14 +105,7 @@
$ hg debugdirstate --no-dates
n 644 10 set inside/f1
-Can't commit empty files
+Can commit empty files
$ touch inside/c; hg add inside/c; hg commit -qm _; hg verify -q
- warning: revlog 'data/inside/c.i' not in fncache!
- 4: empty or missing inside/c
- inside/c@4: manifest refers to unknown revision 000000000000
- 1 warnings encountered!
- hint: run "hg debugrebuildfncache" to recover from corrupt fncache
- 2 integrity errors encountered!
- (first damaged changeset appears to be 4)
- [1]
+ $ hg cat -r . inside/c