view tests/test-commit-multiple.t @ 25708:d3d32643c060

wireproto: correctly escape batched args and responses (issue4739)

This issue appears to be as old as wireproto batching itself: I can
reproduce the failure as far back as 08ef6b5f3715 trivially by
rebasing the test changes in this patch, which was back in the 1.9
era. I didn't test before that change, because prior to that the
testfile has a different name and I'm lazy.

Note that the test thought it was checking this case, but it actually
wasn't: it put a literal ; in the arg and response for its greet
command, but the mangle/unmangle step defined in the test meant that
instead of "Fo, =;o" going over the wire, "Gp-!><p" went instead,
which doesn't contain any special characters (those being [.=;]) and
thus not exercising the escaping. The test has been updated to use
pre-unmangled special characters, so the request is now "Fo+<:o",
which mangles to "Gp,=;p". I have confirmed that the test fails
without the adjustment to the escaping rules in wireproto.py.

No existing clients of RPC batching were depending on the old behavior
in any way. The only *actual* users of batchable RPCs in core were:

1) largefiles, wherein it batches up many statlfile calls. It sends
hexlified hashes over the wire and gets a 0, 1, or 2 back as a
response. No risk of special characters.

2) setdiscovery, which was using heads() and known(), both of which
communicate via hexlified nodes. Again, no risk of special characters.

Since the escaping functionality has been completely broken since it
was introduced, we know that it has no users. As such, we can change
the escaping mechanism without having to worry about backwards
compatibility issues.

For the curious, this was detected by chance: it happens that the
lz4-compressed text of a test file for remotefilelog compressed to
something containing a ;, which then caused the failure when I moved
remotefilelog to using batching for file content fetching.

# reproduce issue2264, issue2516

create test repo
  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > transplant =
  > EOF
  $ hg init repo
  $ cd repo
  $ template="{rev}  {desc|firstline}  [{branch}]\n"

# we need to start out with two changesets on the default branch
# in order to avoid the cute little optimization where transplant
# pulls rather than transplants
add initial changesets
  $ echo feature1 > file1
  $ hg ci -Am"feature 1"
  adding file1
  $ echo feature2 >> file2
  $ hg ci -Am"feature 2"
  adding file2

# The changes to 'bugfix' are enough to show the bug: in fact, with only
# those changes, it's a very noisy crash ("RuntimeError: nothing
# committed after transplant").  But if we modify a second file in the
# transplanted changesets, the bug is much more subtle: transplant
# silently drops the second change to 'bugfix' on the floor, and we only
# see it when we run 'hg status' after transplanting.  Subtle data loss
# bugs are worse than crashes, so reproduce the subtle case here.
commit bug fixes on bug fix branch
  $ hg branch fixes
  marked working directory as branch fixes
  (branches are permanent and global, did you want a bookmark?)
  $ echo fix1 > bugfix
  $ echo fix1 >> file1
  $ hg ci -Am"fix 1"
  adding bugfix
  $ echo fix2 > bugfix
  $ echo fix2 >> file1
  $ hg ci -Am"fix 2"
  $ hg log -G --template="$template"
  @  3  fix 2  [fixes]
  |
  o  2  fix 1  [fixes]
  |
  o  1  feature 2  [default]
  |
  o  0  feature 1  [default]
  
transplant bug fixes onto release branch
  $ hg update 0
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ hg branch release
  marked working directory as branch release
  $ hg transplant 2 3
  applying [0-9a-f]{12} (re)
  [0-9a-f]{12} transplanted to [0-9a-f]{12} (re)
  applying [0-9a-f]{12} (re)
  [0-9a-f]{12} transplanted to [0-9a-f]{12} (re)
  $ hg log -G --template="$template"
  @  5  fix 2  [release]
  |
  o  4  fix 1  [release]
  |
  | o  3  fix 2  [fixes]
  | |
  | o  2  fix 1  [fixes]
  | |
  | o  1  feature 2  [default]
  |/
  o  0  feature 1  [default]
  
  $ hg status
  $ hg status --rev 0:4
  M file1
  A bugfix
  $ hg status --rev 4:5
  M bugfix
  M file1

now test that we fixed the bug for all scripts/extensions
  $ cat > $TESTTMP/committwice.py <<__EOF__
  > from mercurial import ui, hg, match, node
  > from time import sleep
  > 
  > def replacebyte(fn, b):
  >     f = open(fn, "rb+")
  >     f.seek(0, 0)
  >     f.write(b)
  >     f.close()
  > 
  > def printfiles(repo, rev):
  >     print "revision %s files: %s" % (rev, repo[rev].files())
  > 
  > repo = hg.repository(ui.ui(), '.')
  > assert len(repo) == 6, \
  >        "initial: len(repo): %d, expected: 6" % len(repo)
  > 
  > replacebyte("bugfix", "u")
  > sleep(2)
  > try:
  >     print "PRE: len(repo): %d" % len(repo)
  >     wlock = repo.wlock()
  >     lock = repo.lock()
  >     replacebyte("file1", "x")
  >     repo.commit(text="x", user="test", date=(0, 0))
  >     replacebyte("file1", "y")
  >     repo.commit(text="y", user="test", date=(0, 0))
  >     print "POST: len(repo): %d" % len(repo)
  > finally:
  >     lock.release()
  >     wlock.release()
  > printfiles(repo, 6)
  > printfiles(repo, 7)
  > __EOF__
  $ $PYTHON $TESTTMP/committwice.py
  PRE: len(repo): 6
  POST: len(repo): 8
  revision 6 files: ['bugfix', 'file1']
  revision 7 files: ['file1']

Do a size-preserving modification outside of that process
  $ echo abcd > bugfix
  $ hg status
  M bugfix
  $ hg log --template "{rev}  {desc}  {files}\n" -r5:
  5  fix 2  bugfix file1
  6  x  bugfix file1
  7  y  file1

  $ cd ..