sparse-revlog: only refine delta candidates in the sparse case (
issue6006)
Starting with
5aef5afa8654, a valid delta parent might be "refined". This
allows repository using sparse-revlog to produce better delta chain by using
better intermediate snapshot base.
However, this refining step was performed in all cases, including for
repository not using sparse-revlog. This could produce a strange chain in the
general delta case and corrupted repository in the non-general delta case.
We now skip this step unless sparse-revlog is in use.
In issue 6006, Yuya Nishihara provided a test case using an external
repository, so we did not include it. Finding "laboratory" condition to
reproduce this case and implementing an efficient test reproducing it is a bit
tricky. We do not foresee to have the time to provide one by the release date.
Differential Revision: https://phab.mercurial-scm.org/D5197
--- a/mercurial/revlogutils/deltas.py Mon Oct 29 16:23:42 2018 -0400
+++ b/mercurial/revlogutils/deltas.py Wed Oct 31 11:02:08 2018 +0100
@@ -646,6 +646,11 @@
if good is not None:
break
+ # If sparse revlog is enabled, we can try to refine the available deltas
+ if not revlog._sparserevlog:
+ yield None
+ return
+
# if we have a refinable value, try to refine it
if good is not None and good not in (p1, p2) and revlog.issnapshot(good):
# refine snapshot down