view tests/test-merge-symlinks @ 11638:79231258503b stable

transplant: crash if repo.commit() finds nothing to commit

(makes issue2135, issue2264 more obvious, but does nothing to fix
either one)

This seems to happen in two distinct cases:
  * patch.patch() claims success but changes nothing (e.g.
    the transplanted changeset adds an empty file that already
    exists)
  * patch.patch() makes changes, but repo.status() fails to report them

Both of these seem like bugs in other parts of Mercurial, so arguably
it's not transplant's job to detect the failure to commit.  However:
  * detecting the problem as soon as possible is desirable
  * it prevents a more obscure crash later, in transplants.write()
  * there might be other lurking (or future) bugs that cause
    repo.commit() to do nothing

Also, in the case of issue2264 (source changesets silently dropped by
transplant), the only way to spot the problem currently is the crash
in transplants.write().  Failure to transplant a patch should abort
immediately, whether it's user error (patch does not apply) or a
Mercurial bug (e.g. repo.status() failing to report changes).

#!/bin/sh

cat > echo.py <<EOF
#!/usr/bin/env python
import os, sys
try:
    import msvcrt
    msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
    msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
except ImportError:
    pass

for k in ('HG_FILE', 'HG_MY_ISLINK', 'HG_OTHER_ISLINK', 'HG_BASE_ISLINK'):
    print k, os.environ[k]
EOF

# Create 2 heads containing the same file, once as
# a file, once as a link. Bundle was generated with:
#
# hg init t
# cd t
# echo a > a
# hg ci -qAm t0 -d '0 0'
# echo l > l
# hg ci -qAm t1 -d '1 0'
# hg up -C 0
# ln -s a l
# hg ci -qAm t2 -d '2 0'
# echo l2 > l2
# hg ci -qAm t3 -d '3 0'

hg init t
cd t
hg -q pull "$TESTDIR/test-merge-symlinks.hg"
hg up -C 3

# Merge them and display *_ISLINK vars
echo % merge heads
HGMERGE="python ../echo.py" hg merge

# Test working directory symlink bit calculation wrt copies,
# especially on non-supporting systems.
echo % merge working directory
hg up -C 2
hg copy l l2
HGMERGE="python ../echo.py" hg up 3