view tests/test-missing-capability.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
author Matt Harbison <matt_harbison@yahoo.com>
date Thu, 23 May 2019 21:54:24 -0400
parents d3cc9a8df63a
children 8d72e29ad1e0
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Checking how hg behaves when one side of a pull/push doesn't support
some capability (because it's running an older hg version, usually).

  $ hg init repo1
  $ cd repo1
  $ echo a > a; hg add -q a; hg commit -q -m a
  $ hg bookmark a
  $ hg clone -q . ../repo2
  $ cd ../repo2

  $ touch $TESTTMP/disable-lookup.py
  $ disable_cap() {
  >   rm -f $TESTTMP/disable-lookup.pyc # pyc caching is buggy
  >   cat <<EOF > $TESTTMP/disable-lookup.py
  > from mercurial import extensions, wireprotov1server
  > def wcapabilities(orig, *args, **kwargs):
  >   cap = orig(*args, **kwargs)
  >   cap.remove(b'$1')
  >   return cap
  > extensions.wrapfunction(wireprotov1server, '_capabilities', wcapabilities)
  > EOF
  > }
  $ cat >> ../repo1/.hg/hgrc <<EOF
  > [extensions]
  > disable-lookup = $TESTTMP/disable-lookup.py
  > EOF
  $ cat >> .hg/hgrc <<EOF
  > [ui]
  > ssh = "$PYTHON" "$TESTDIR/dummyssh"
  > EOF

  $ hg pull ssh://user@dummy/repo1 -r tip -B a
  pulling from ssh://user@dummy/repo1
  no changes found

  $ disable_cap lookup
  $ hg pull ssh://user@dummy/repo1 -r tip -B a
  pulling from ssh://user@dummy/repo1
  abort: other repository doesn't support revision lookup, so a rev cannot be specified.
  [255]

  $ disable_cap pushkey
  $ hg pull ssh://user@dummy/repo1 -r tip -B a
  pulling from ssh://user@dummy/repo1
  abort: remote bookmark a not found!
  [255]