annotate tests/test-rename-merge1.t @ 17616:9535a0dc41f2

store: implement fncache basic path encoding in C

(This is not yet enabled; it will be turned on in a followup patch.)

The path encoding performed by fncache is complex and (perhaps
surprisingly) slow enough to negatively affect the overall performance
of Mercurial.

For a short path (< 120 bytes), the Python code can be reduced to a fairly
tractable state machine that either determines that nothing needs to be
done in a single pass, or performs the encoding in a second pass.

For longer paths, we avoid the more complicated hashed encoding scheme
for now, and fall back to Python.

Raw performance: I measured in a repo containing 150,000 files in its tip
manifest, with a median path name length of 57 bytes, and 95th percentile
of 96 bytes.

In this repo, the Python code takes 3.1 seconds to encode all path
names, while the hybrid C-and-Python code (called from Python) takes
0.21 seconds, for a speedup of about 14.

Across several other large repositories, I've measured the speedup from
the C code at between 26x and 40x.

For path names above 120 bytes where we must fall back to Python for
hashed encoding, the speedup is about 1.7x.  Thus absolute performance
will depend strongly on the characteristics of a particular repository.

  $ hg init

  $ echo "[merge]" >> .hg/hgrc
  $ echo "followcopies = 1" >> .hg/hgrc

  $ echo foo > a
  $ echo foo > a2
  $ hg add a a2
  $ hg ci -m "start"

  $ hg mv a b
  $ hg mv a2 b2
  $ hg ci -m "rename"

  $ hg co 0
  2 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ echo blahblah > a
  $ echo blahblah > a2
  $ hg mv a2 c2
  $ hg ci -m "modify"
  created new head

  $ hg merge -y --debug
    searching for copies back to rev 1
    unmatched files in local:
     c2
    unmatched files in other:
     b
     b2
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     c2 -> a2 !
     b -> a *
     b2 -> a2 !
    checking for directory renames
   a2: divergent renames -> dr
  resolving manifests
   overwrite: False, partial: False
   ancestor: af1939970a1c, local: 044f8520aeeb+, remote: 85c198ef2f6c
   a: remote moved to b -> m
   b2: remote created -> g
  preserving a for resolve of b
  removing a
  updating: a 1/3 files (33.33%)
  picked tool 'internal:merge' for b (binary False symlink False)
  merging a and b to b
  my b@044f8520aeeb+ other b@85c198ef2f6c ancestor a@af1939970a1c
   premerge successful
  updating: a2 2/3 files (66.67%)
  note: possible conflict - a2 was renamed multiple times to:
   c2
   b2
  updating: b2 3/3 files (100.00%)
  getting b2
  1 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status -AC
  M b
    a
  M b2
  R a
  C c2

  $ cat b
  blahblah

  $ hg ci -m "merge"

  $ hg debugindex b
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0      67  .....       1 57eacc201a7f 000000000000 000000000000 (re)
       1        67      72  .....       3 4727ba907962 000000000000 57eacc201a7f (re)

  $ hg debugrename b
  b renamed from a:dd03b83622e78778b403775d0d074b9ac7387a66

This used to trigger a "divergent renames" warning, despite no renames

  $ hg cp b b3
  $ hg cp b b4
  $ hg ci -A -m 'copy b twice'
  $ hg up eb92d88a9712
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg up
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg rm b3 b4
  $ hg ci -m 'clean up a bit of our mess'

We'd rather not warn on divergent renames done in the same changeset (issue2113)

  $ hg cp b b3
  $ hg mv b b4
  $ hg ci -A -m 'divergent renames in same changeset'
  $ hg up c761c6948de0
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg up
  2 files updated, 0 files merged, 1 files removed, 0 files unresolved

Check for issue2642

  $ hg init t
  $ cd t

  $ echo c0 > f1
  $ hg ci -Aqm0

  $ hg up null -q
  $ echo c1 > f1 # backport
  $ hg ci -Aqm1
  $ hg mv f1 f2
  $ hg ci -qm2

  $ hg up 0 -q
  $ hg merge 1 -q --tool internal:local
  $ hg ci -qm3

  $ hg merge 2
  merging f1 and f2 to f2
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f2
  c0

  $ cd ..

Check for issue2089

  $ hg init repo2089
  $ cd repo2089

  $ echo c0 > f1
  $ hg ci -Aqm0

  $ hg up null -q
  $ echo c1 > f1
  $ hg ci -Aqm1

  $ hg up 0 -q
  $ hg merge 1 -q --tool internal:local
  $ echo c2 > f1
  $ hg ci -qm2

  $ hg up 1 -q
  $ hg mv f1 f2
  $ hg ci -Aqm3

  $ hg up 2 -q
  $ hg merge 3
  merging f1 and f2 to f2
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cat f2
  c2

  $ cd ..

Check for issue3074

  $ hg init repo3074
  $ cd repo3074
  $ echo foo > file
  $ hg add file
  $ hg commit -m "added file"
  $ hg mv file newfile
  $ hg commit -m "renamed file"
  $ hg update 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg rm file
  $ hg commit -m "deleted file"
  created new head
  $ hg merge --debug
    searching for copies back to rev 1
    unmatched files in other:
     newfile
    all copies found (* = to merge, ! = divergent, % = renamed and deleted):
     newfile -> file %
    checking for directory renames
   file: rename and delete -> rd
  resolving manifests
   overwrite: False, partial: False
   ancestor: 19d7f95df299, local: 0084274f6b67+, remote: 5d32493049f0
   newfile: remote created -> g
  updating: file 1/2 files (50.00%)
  note: possible conflict - file was deleted and renamed to:
   newfile
  updating: newfile 2/2 files (100.00%)
  getting newfile
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg status
  M newfile
  $ cd ..