view tests/test-merge-symlinks.t @ 27372:a79cba6cb206

help: add documentation for changegroup formats

There is no formal location for spec-like technical/internal docs. The
repository makes sense as such a location because spec-like
documentation should be reviewed (ruling out a wiki). mpm has also
stated that he would like this documentation to be part of the
built-in help system. So, we establish an "internals" sub-directory
to hold this class of documentation.

The format of changegroups does not appear to be documented anywhere,
even in source code. It therefore seemed like an appropriate first thing
to document.

This patch adds low-level documentation of versions 1 and 2 of the
changegroup foromat. It currently only describes the raw data format.
There is probably room to write higher-level documentation on strategies
for producing and consuming the data. We'll leave that for another day.

The added file is not yet accessible via `hg help` nor via hgweb.
Support for this will follow in subsequent patches.

  $ 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/bundles/test-merge-symlinks.hg"
  $ hg up -C 3
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

Merge them and display *_ISLINK vars
merge heads

  $ hg merge --tool="python ../echo.py"
  merging l
  HG_FILE l
  HG_MY_ISLINK 1
  HG_OTHER_ISLINK 0
  HG_BASE_ISLINK 0
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Test working directory symlink bit calculation wrt copies,
especially on non-supporting systems.
merge working directory

  $ hg up -C 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg copy l l2
  $ HGMERGE="python ../echo.py" hg up 3
  merging l2
  HG_FILE l2
  HG_MY_ISLINK 1
  HG_OTHER_ISLINK 0
  HG_BASE_ISLINK 0
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved

  $ cd ..