view tests/test-merge-default.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

  $ hg init
  $ echo a > a
  $ hg commit -A -ma
  adding a

  $ echo b >> a
  $ hg commit -mb

  $ echo c >> a
  $ hg commit -mc

  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo d >> a
  $ hg commit -md
  created new head

  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo e >> a
  $ hg commit -me
  created new head

  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Should fail because not at a head:

  $ hg merge
  abort: working directory not at a head revision
  (use 'hg update' or merge with an explicit revision)
  [255]

  $ hg up
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "f25cbe84d8b3: e"
  2 other heads for branch "default"

Should fail because > 2 heads:

  $ HGMERGE=internal:other; export HGMERGE
  $ hg merge
  abort: branch 'default' has 3 heads - please merge with an explicit rev
  (run 'hg heads .' to see heads)
  [255]

Should succeed:

  $ hg merge 2
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg id -Tjson
  [
   {
    "bookmarks": [],
    "branch": "default",
    "dirty": "+",
    "id": "f25cbe84d8b320e298e7703f18a25a3959518c23+2d95304fed5d89bc9d70b2a0d02f0d567469c3ab+",
    "node": "ffffffffffffffffffffffffffffffffffffffff",
    "parents": ["f25cbe84d8b320e298e7703f18a25a3959518c23", "2d95304fed5d89bc9d70b2a0d02f0d567469c3ab"],
    "tags": ["tip"]
   }
  ]
  $ hg commit -mm1

Should succeed - 2 heads:

  $ hg merge -P
  changeset:   3:ea9ff125ff88
  parent:      1:1846eede8b68
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     d
  
  $ hg merge
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -mm2

  $ hg id -r 1 -Tjson
  [
   {
    "bookmarks": [],
    "branch": "default",
    "id": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
    "node": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
    "tags": []
   }
  ]

Should fail because at tip:

  $ hg merge
  abort: nothing to merge
  [255]

  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Should fail because there is only one head:

  $ hg merge
  abort: nothing to merge
  (use 'hg update' instead)
  [255]

  $ hg up 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo f >> a
  $ hg branch foobranch
  marked working directory as branch foobranch
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -mf

Should fail because merge with other branch:

  $ hg merge
  abort: branch 'foobranch' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]


Test for issue2043: ensure that 'merge -P' shows ancestors of 6 that
are not ancestors of 7, regardless of where their common ancestors are.

Merge preview not affected by common ancestor:

  $ hg up -q 7
  $ hg merge -q -P 6
  2:2d95304fed5d
  4:f25cbe84d8b3
  5:a431fabd6039
  6:e88e33f3bf62

Test experimental destination revset

  $ hg log -r '_destmerge()'
  abort: branch 'foobranch' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]

(on a branch with a two heads)

  $ hg up 5
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo f >> a
  $ hg commit -mf
  created new head
  $ hg log -r '_destmerge()'
  changeset:   6:e88e33f3bf62
  parent:      5:a431fabd6039
  parent:      3:ea9ff125ff88
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     m2
  

(from the other head)

  $ hg log -r '_destmerge(e88e33f3bf62)'
  changeset:   8:b613918999e2
  tag:         tip
  parent:      5:a431fabd6039
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     f
  

(from unrelated branch)

  $ hg log -r '_destmerge(foobranch)'
  abort: branch 'foobranch' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]