view tests/test-issue842.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

http://mercurial.selenic.com/bts/issue842

  $ hg init
  $ echo foo > a
  $ hg ci -Ama
  adding a

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo bar > a

Should issue new head warning:

  $ hg ci -Amb
  adding a
  created new head

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo stuffy > a

Should not issue new head warning:

  $ hg ci -q -Amc

  $ hg up -r0000
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo crap > a
  $ hg branch testing
  marked working directory as branch testing
  (branches are permanent and global, did you want a bookmark?)

Should not issue warning:

  $ hg ci -q -Amd