view tests/test-atomictempfile.py @ 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

import os
import glob
from mercurial.util import atomictempfile

# basic usage
def test1_simple():
    if os.path.exists('foo'):
        os.remove('foo')
    file = atomictempfile('foo')
    (dir, basename) = os.path.split(file._tempname)
    assert not os.path.isfile('foo')
    assert basename in glob.glob('.foo-*')

    file.write('argh\n')
    file.close()

    assert os.path.isfile('foo')
    assert basename not in glob.glob('.foo-*')
    print 'OK'

# discard() removes the temp file without making the write permanent
def test2_discard():
    if os.path.exists('foo'):
        os.remove('foo')
    file = atomictempfile('foo')
    (dir, basename) = os.path.split(file._tempname)

    file.write('yo\n')
    file.discard()

    assert not os.path.isfile('foo')
    assert basename not in os.listdir('.')
    print 'OK'

# if a programmer screws up and passes bad args to atomictempfile, they
# get a plain ordinary TypeError, not infinite recursion
def test3_oops():
    try:
        file = atomictempfile()
    except TypeError:
        print "OK"
    else:
        print "expected TypeError"

if __name__ == '__main__':
    test1_simple()
    test2_discard()
    test3_oops()