view tests/test-merge-default.t @ 16506:fc4e0fecf403 stable

patch: fix patch hunk/metdata synchronization (issue3384)

Git patches are parsed in two phases: 1) extract metadata, 2) parse actual
deltas and merge them with the previous metadata. We do this to avoid
dependency issues like "modify a; copy a to b", where "b" must be copied from
the unmodified "a".

Issue3384 is caused by flaky code I wrote to synchronize the patch metadata
with the emitted hunk:

 if (gitpatches and
     (gitpatches[-1][0] == afile or gitpatches[-1][1] == bfile)):
     gp = gitpatches.pop()[2]

With a patch like:

 diff --git a/a b/c
 copy from a
 copy to c
 --- a/a
 +++ b/c
 @@ -1,1 +1,2 @@
  a
 +a
 @@ -2,1 +2,2 @@
  a
 +a
 diff --git a/a b/a
 --- a/a
 +++ b/a
 @@ -1,1 +1,2 @@
  a
 +b

the first hunk of the first block is matched with the metadata for the block
"diff --git a/a b/c", then the second hunk of the first block is matched with
the metadata of the second block "diff --git a/a b/a", because of the "or" in
the code paste above. Turning the "or" into an "and" is not enough as we have
to deal with /dev/null cases for each file.

We I remove this broken piece of code:

 # copy/rename + modify should modify target, not source
 if gp.op in ('COPY', 'DELETE', 'RENAME', 'ADD') or gp.mode:
     afile = bfile

because "afile = bfile" set "afile" to stuff like "b/file" instead of "a/file",
and because this only happens for git patches, which afile/bfile are ignored
anyway by applydiff().

v2:
- Avoid a traceback on git metadata desynchronization

  $ 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: branch 'default' has 3 heads - please merge with an explicit rev
  (run 'hg heads .' to see heads)
  [255]

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

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 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

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 least common
ancestor is.

Merge preview not affected by common ancestor:

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