view tests/test-patch-offset.t @ 41304:76873548b051 stable

partialdiscovery: avoid `undecided` related computation sooner than necessary

Changeset 1d30be90c move the update of the `undecided` set within the
`partialdiscovery` object in order to clarify the API.

The update to the `undecided` set was unconditional in 1d30be90c and the first
access to the `self.undecided` property triggered the initial computation of
the set of undecided revisions. As a result, the set was computed much
earlier, at a time where less information is available, immediately followed
by an update of this set to remove common revisions.

To fix this regression, we ignore the `undecided` related logic in
`addcommons` when that `undecided` set has not been computed yet. Code that
actually needs to know the `undecided` set will trigger its computation later.
The change has no effects on semantic because the initial computation
`undecided` set takes all knowns `common` into account.

Example performance running `hg debugdiscovery` from a pypy repo missing 10
changesets:

870a89c6909d: 52.3ms (regression parent)
1d30be90c9dc: 72.0ms (regression)
5a5f504a7175: 64.8ms (this fix parent)
this fix:     52.6ms

  $ cat > writepatterns.py <<EOF
  > import sys
  > 
  > path = sys.argv[1]
  > patterns = sys.argv[2:]
  > 
  > fp = open(path, 'wb')
  > for pattern in patterns:
  >     count = int(pattern[0:-1])
  >     char = pattern[-1].encode('utf8') + b'\n'
  >     fp.write(char*count)
  > fp.close()
  > EOF

prepare repo

  $ hg init a
  $ cd a

These initial lines of Xs were not in the original file used to generate
the patch.  So all the patch hunks need to be applied to a constant offset
within this file.  If the offset isn't tracked then the hunks can be
applied to the wrong lines of this file.

  $ "$PYTHON" ../writepatterns.py a 34X 10A 1B 10A 1C 10A 1B 10A 1D 10A 1B 10A 1E 10A 1B 10A
  $ hg commit -Am adda
  adding a

This is a cleaner patch generated via diff
In this case it reproduces the problem when
the output of hg export does not
import patch

  $ hg import -v -m 'b' -d '2 0' - <<EOF
  > --- a/a	2009-12-08 19:26:17.000000000 -0800
  > +++ b/a	2009-12-08 19:26:17.000000000 -0800
  > @@ -9,7 +9,7 @@
  >  A
  >  A
  >  B
  > -A
  > +a
  >  A
  >  A
  >  A
  > @@ -53,7 +53,7 @@
  >  A
  >  A
  >  B
  > -A
  > +a
  >  A
  >  A
  >  A
  > @@ -75,7 +75,7 @@
  >  A
  >  A
  >  B
  > -A
  > +a
  >  A
  >  A
  >  A
  > EOF
  applying patch from stdin
  patching file a
  Hunk #1 succeeded at 43 (offset 34 lines).
  Hunk #2 succeeded at 87 (offset 34 lines).
  Hunk #3 succeeded at 109 (offset 34 lines).
  committing files:
  a
  committing manifest
  committing changelog
  created 189885cecb41

compare imported changes against reference file

  $ "$PYTHON" ../writepatterns.py aref 34X 10A 1B 1a 9A 1C 10A 1B 10A 1D 10A 1B 1a 9A 1E 10A 1B 1a 9A
  $ diff aref a

  $ cd ..