view tests/test-bisect3.t @ 23702:c48924787eaa

filectx.parents: enforce changeid of parent to be in own changectx ancestors

Because of the way filenodes are computed, you can have multiple changesets
"introducing" the same file revision. For example, in the changeset graph
below, changeset 2 and 3 both change a file -to- and -from- the same content.

  o 3: content = new
  |
  | o 2: content = new
  |/
  o 1: content = old

In such cases, the file revision is create once, when 2 is added, and just reused
for 3. So the file change in '3' (from "old" to "new)" has no linkrev pointing
to it).  We'll call this situation "linkrev-shadowing". As the linkrev is used for
optimization purposes when walking a file history, the linkrev-shadowing
results in an unexpected jump to another branch during such a walk.. This leads to
multiple bugs with log, annotate and rename detection.

One element to fix such bugs is to ensure that walking the file history sticks on
the same topology as the changeset's history. For this purpose, we extend the
logic in 'basefilectx.parents' so that it always defines the proper changeset
to associate the parent file revision with. This "proper" changeset has to be an
ancestor of the changeset associated with the child file revision.

This logic is performed in the '_adjustlinkrev' function. This function is
given the starting changeset and all the information regarding the parent file
revision. If the linkrev for the file revision is an ancestor of the starting
changeset, the linkrev is valid and will be used. If it is not, we detected a
topological jump caused by linkrev shadowing, we are going to walk the
ancestors of the starting changeset until we find one setting the file to the
revision we are trying to create.

The performance impact appears acceptable:

- We are walking the changelog once for each filelog traversal (as there should
  be no overlap between searches),

- changelog traversal itself is fairly cheap, compared to what is likely going
  to be perform on the result on the filelog traversal,

- We only touch the manifest for ancestors touching the file, And such
  changesets are likely to be the one introducing the file. (except in
  pathological cases involving merge),

- We use manifest diff instead of full manifest unpacking to check manifest
  content, so it does not involve applying multiple diffs in most case.

- linkrev shadowing is not the common case.

Tests for fixed issues in log, annotate and rename detection have been
added.

But this changeset does not solve all problems. It fixes -ancestry-
computation, but if the linkrev-shadowed changesets is the starting one, we'll
still get things wrong. We'll have to fix the bootstrapping of such operations
in a later changeset. Also, the usage of `hg log FILE`  without --follow still
has issues with linkrev pointing to hidden changesets, because it relies on the
`filelog` revset which implement its own traversal logic that is still to be
fixed.

Thanks goes to:
- Matt Mackall: for nudging me in the right direction
- Julien Cristau and Rémi Cardona: for keep telling me linkrev bug were an
  evolution show stopper for 3 years.
- Durham Goode: for finding a new linkrev issue every few weeks
- Mads Kiilerich: for that last rename bug who raise this topic over my
  anoyance limit.

# Here we create a simple DAG which has just enough of the required
# topology to test all the bisection status labels:
#
#           13--14
#          /
#   0--1--2--3---------9--10--11--12
#       \             /
#        4--5--6--7--8


  $ hg init

  $ echo '0' >a
  $ hg add a
  $ hg ci -u test -d '0 0' -m '0'
  $ echo '1' >a
  $ hg ci -u test -d '1 0' -m '1'

branch 2-3

  $ echo '2' >b
  $ hg add b
  $ hg ci -u test -d '2 0' -m '2'
  $ echo '3' >b
  $ hg ci -u test -d '3 0' -m '3'

branch 4-8

  $ hg up -r 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '4' >c
  $ hg add c
  $ hg ci -u test -d '4 0' -m '4'
  created new head
  $ echo '5' >c
  $ hg ci -u test -d '5 0' -m '5'
  $ echo '6' >c
  $ hg ci -u test -d '6 0' -m '6'
  $ echo '7' >c
  $ hg ci -u test -d '7 0' -m '7'
  $ echo '8' >c
  $ hg ci -u test -d '8 0' -m '8'

merge

  $ hg merge -r 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -u test -d '9 0' -m '9=8+3'

  $ echo '10' >a
  $ hg ci -u test -d '10 0' -m '10'
  $ echo '11' >a
  $ hg ci -u test -d '11 0' -m '11'
  $ echo '12' >a
  $ hg ci -u test -d '12 0' -m '12'

unrelated branch

  $ hg up -r 3
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo '13' >d
  $ hg add d
  $ hg ci -u test -d '13 0' -m '13'
  created new head
  $ echo '14' >d
  $ hg ci -u test -d '14 0' -m '14'

mark changesets

  $ hg bisect --reset
  $ hg bisect --good 4
  $ hg bisect --good 6
  $ hg bisect --bad 12
  Testing changeset 9:2197c557e14c (6 changesets remaining, ~2 tests)
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect --bad 10
  Testing changeset 8:e74a86251f58 (4 changesets remaining, ~2 tests)
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg bisect --skip 7
  Testing changeset 8:e74a86251f58 (4 changesets remaining, ~2 tests)
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

test template

  $ hg log --template '{rev}:{node|short} {bisect}\n'
  14:cbf2f3105bbf 
  13:e07efca37c43 
  12:98c6b56349c0 bad
  11:03f491376e63 bad (implicit)
  10:c012b15e2409 bad
  9:2197c557e14c untested
  8:e74a86251f58 untested
  7:a5f87041c899 skipped
  6:7d997bedcd8d good
  5:2dd1875f1028 good (implicit)
  4:2a1daef14cd4 good
  3:8417d459b90c ignored
  2:e1355ee1f23e ignored
  1:ce7c85e06a9f good (implicit)
  0:b4e73ffab476 good (implicit)
  $ hg log --template '{bisect|shortbisect} {rev}:{node|short}\n'
    14:cbf2f3105bbf
    13:e07efca37c43
  B 12:98c6b56349c0
  B 11:03f491376e63
  B 10:c012b15e2409
  U 9:2197c557e14c
  U 8:e74a86251f58
  S 7:a5f87041c899
  G 6:7d997bedcd8d
  G 5:2dd1875f1028
  G 4:2a1daef14cd4
  I 3:8417d459b90c
  I 2:e1355ee1f23e
  G 1:ce7c85e06a9f
  G 0:b4e73ffab476

test style

  $ hg log --style bisect
  changeset:   14:cbf2f3105bbf
  bisect:      
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:14 1970 +0000
  summary:     14
  
  changeset:   13:e07efca37c43
  bisect:      
  parent:      3:8417d459b90c
  user:        test
  date:        Thu Jan 01 00:00:13 1970 +0000
  summary:     13
  
  changeset:   12:98c6b56349c0
  bisect:      bad
  user:        test
  date:        Thu Jan 01 00:00:12 1970 +0000
  summary:     12
  
  changeset:   11:03f491376e63
  bisect:      bad (implicit)
  user:        test
  date:        Thu Jan 01 00:00:11 1970 +0000
  summary:     11
  
  changeset:   10:c012b15e2409
  bisect:      bad
  user:        test
  date:        Thu Jan 01 00:00:10 1970 +0000
  summary:     10
  
  changeset:   9:2197c557e14c
  bisect:      untested
  parent:      8:e74a86251f58
  parent:      3:8417d459b90c
  user:        test
  date:        Thu Jan 01 00:00:09 1970 +0000
  summary:     9=8+3
  
  changeset:   8:e74a86251f58
  bisect:      untested
  user:        test
  date:        Thu Jan 01 00:00:08 1970 +0000
  summary:     8
  
  changeset:   7:a5f87041c899
  bisect:      skipped
  user:        test
  date:        Thu Jan 01 00:00:07 1970 +0000
  summary:     7
  
  changeset:   6:7d997bedcd8d
  bisect:      good
  user:        test
  date:        Thu Jan 01 00:00:06 1970 +0000
  summary:     6
  
  changeset:   5:2dd1875f1028
  bisect:      good (implicit)
  user:        test
  date:        Thu Jan 01 00:00:05 1970 +0000
  summary:     5
  
  changeset:   4:2a1daef14cd4
  bisect:      good
  parent:      1:ce7c85e06a9f
  user:        test
  date:        Thu Jan 01 00:00:04 1970 +0000
  summary:     4
  
  changeset:   3:8417d459b90c
  bisect:      ignored
  user:        test
  date:        Thu Jan 01 00:00:03 1970 +0000
  summary:     3
  
  changeset:   2:e1355ee1f23e
  bisect:      ignored
  user:        test
  date:        Thu Jan 01 00:00:02 1970 +0000
  summary:     2
  
  changeset:   1:ce7c85e06a9f
  bisect:      good (implicit)
  user:        test
  date:        Thu Jan 01 00:00:01 1970 +0000
  summary:     1
  
  changeset:   0:b4e73ffab476
  bisect:      good (implicit)
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     0
  
  $ hg log --quiet --style bisect
    14:cbf2f3105bbf
    13:e07efca37c43
  B 12:98c6b56349c0
  B 11:03f491376e63
  B 10:c012b15e2409
  U 9:2197c557e14c
  U 8:e74a86251f58
  S 7:a5f87041c899
  G 6:7d997bedcd8d
  G 5:2dd1875f1028
  G 4:2a1daef14cd4
  I 3:8417d459b90c
  I 2:e1355ee1f23e
  G 1:ce7c85e06a9f
  G 0:b4e73ffab476