view tests/test-bisect3.t @ 48507:58a3be48ddd2

simplemerge: stop merging file flags

As 384df4db6520 (merge: merge file flags together with file content,
2013-01-09) explains, we shouldn't do a 3-way merge of the
symlink. However, since 84614212ae39 (flags: actually merge flags in
simplemerge, 2020-05-16), we do that in
`simplemerge.simplemerge()`. What's more, the merging of the
executable flag there isn't actually necessary; it was made a no-op by
the very next commit, i.e. 4234c9af515d (flags: read flag from
dirstate/disk for workingcopyctx (issue5743), 2020-05-16).

I found the overall flag-merging code (not the bit in
`simplemerge.py`) very hard to follow, but I think I now finally
understand how it works. `mergestate.resolve()` calculates the merged
file flags and sets them on the local side of the merge (confusingly
by calling `_restore_backup()`). Then it calls
`filemerge.filemerge()`, which in turn calls
`simplemerge.simplemerge()` (if premerge is enabled). That means that
the flags on the local side `fcs.flags()` are already correct when the
flag-merging code in `simplemerge.simplemerge()` runs. Interestingly,
that code still works when the local side already has the merged
value, it just doesn't change the value. Here's a truth table to
explain why:

```
BLOMCAR
0000000
0011111
0101011
0111111
1000000
1010000
1100000
1111101
```

B: Base
L: Local
O: Other
M: Merged flags from `mergestate.resolve()`, i.e. what's called "local"
   when we get to `simplemerge.simplemerge()`
C: `commonflags` in `simplemerge.simplemerge()`, i.e. `M & O`
A: `addedflags` in `simplemerge.simplemerge()`, i.e. `(M ^ O) - B`
R: Re-merged flags `simplemerge.simplemerge()`, i.e. `C | A`

As you can see, the re-merged flags are always unchanged compared to
the initial merged flags (R equals M).

Therefore, this patch effectively backs out 84614212ae39. (I might
later refactor this code to have the flags explicitly passed in.)

`simplemerge.simplemerge()` is also called from
`contrib/simplemerge.py`, but that code never passes any flags.

Differential Revision: https://phab.mercurial-scm.org/D11879

# 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 "9=8+3" (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 "8" (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 "8" (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

  $ hg --config extensions.color= --color=debug log --quiet --style bisect
  [log.bisect| ] 14:cbf2f3105bbf
  [log.bisect| ] 13:e07efca37c43
  [log.bisect bisect.bad|B] 12:98c6b56349c0
  [log.bisect bisect.bad|B] 11:03f491376e63
  [log.bisect bisect.bad|B] 10:c012b15e2409
  [log.bisect bisect.untested|U] 9:2197c557e14c
  [log.bisect bisect.untested|U] 8:e74a86251f58
  [log.bisect bisect.skipped|S] 7:a5f87041c899
  [log.bisect bisect.good|G] 6:7d997bedcd8d
  [log.bisect bisect.good|G] 5:2dd1875f1028
  [log.bisect bisect.good|G] 4:2a1daef14cd4
  [log.bisect bisect.ignored|I] 3:8417d459b90c
  [log.bisect bisect.ignored|I] 2:e1355ee1f23e
  [log.bisect bisect.good|G] 1:ce7c85e06a9f
  [log.bisect bisect.good|G] 0:b4e73ffab476