view tests/test-remotefilelog-bundle2.t @ 42377:0546ead39a7e stable

manifest: avoid corruption by dropping removed files with pure (issue5801)

Previously, removed files would simply be marked by overwriting the first byte
with NUL and dropping their entry in `self.position`.  But no effort was made to
ignore them when compacting the dictionary into text form.  This allowed them to
slip into the manifest revision, since the code seems to be trying to minimize
the string operations by copying as large a chunk as possible.  As part of this,
compact() walks the existing text based on entries in the `positions` list, and
consumed everything up to the next position entry.   This typically resulted in
a ValueError complaining about unsorted manifest entries.

Sometimes it seems that files do get dropped in large repos- it seems to
correspond to there being a new entry that would take the same slot.  A much
more trivial problem is that if the only changes were removals, `_compact()`
didn't even run because `__delitem__` doesn't add anything to `self.extradata`.
Now there's an explicit variable to flag this, both to allow `_compact()` to
run, and to avoid searching the manifest in cases where there are no removals.

In practice, this behavior was mostly obscured by the check in fastdelta() which
takes a different path that explicitly drops removed files if there are fewer
than 1000 changes.  However, timeless has a repo where after rebasing tens of
commits, a totally different path[1] is taken that bypasses the change count
check and hits this problem.

[1] https://www.mercurial-scm.org/repo/hg/file/2338bdea4474/mercurial/manifest.py#l1511

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ grep generaldelta master/.hg/requires
  generaldelta
  $ cd master
preferuncompressed = False so that we can make both generaldelta and non-generaldelta clones
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > [experimental]
  > bundle2-exp = True
  > [server]
  > preferuncompressed = False
  > EOF
  $ echo x > x
  $ hg commit -qAm x

  $ cd ..

  $ hgcloneshallow ssh://user@dummy/master shallow-generaldelta -q --pull --config experimental.bundle2-exp=True
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
  $ grep generaldelta shallow-generaldelta/.hg/requires
  generaldelta
  $ hgcloneshallow ssh://user@dummy/master shallow-plain -q --pull --config format.usegeneraldelta=False --config format.generaldelta=False --config experimental.bundle2-exp=True
  $ grep generaldelta shallow-plain/.hg/requires
  [1]

  $ cd master
  $ echo a > a
  $ hg commit -qAm a

pull from generaldelta to generaldelta
  $ cd ../shallow-generaldelta
  $ hg pull -u
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets 2fbb8bb2b903
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
push from generaldelta to generaldelta
  $ echo b > b
  $ hg commit -qAm b
  $ hg push
  pushing to ssh://user@dummy/master
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files
pull from generaldelta to non-generaldelta
  $ cd ../shallow-plain
  $ hg pull -u
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 0 changes to 0 files
  new changesets 2fbb8bb2b903:d6788bd632ca
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
push from non-generaldelta to generaldelta
  $ echo c > c
  $ hg commit -qAm c
  $ hg push
  pushing to ssh://user@dummy/master
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files