view tests/test-convert-p4.t @ 26375:3686fa2b8eee

windows: insert file positioning call between reads and writes

fopen() and fdopen() have a unique-to-Windows requirement that
transitions between read and write operations in files opened
in modes r+, w+, and a+ perform a file positioning call
(fsetpos, fseek, or rewind) in between. While the MSDN docs don't
say what will happen if this is not done, observations reveal
that Python raises an IOError with errno 0. Furthermore, I
/think/ this behavior isn't deterministic. But I can reproduce
it reliably with subsequent patches applied that open revlogs
in a+ mode and perform both reads and writes.

This patch introduces a proxy class for file handles opened
in r+, w+, and a+ mode on Windows. The class intercepts calls
and audits whether a file positioning function has been called
between read and write operations. If not, a dummy, no-op seek
to the current file position is performed. This appears to be
sufficient to "trick" Windows into allowing transitions between
read and writes without raising errors.

#require p4

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "convert = " >> $HGRCPATH

create p4 depot
  $ P4ROOT=`pwd`/depot; export P4ROOT
  $ P4AUDIT=$P4ROOT/audit; export P4AUDIT
  $ P4JOURNAL=$P4ROOT/journal; export P4JOURNAL
  $ P4LOG=$P4ROOT/log; export P4LOG
  $ P4PORT=localhost:$HGPORT; export P4PORT
  $ P4DEBUG=1; export P4DEBUG

start the p4 server
  $ [ ! -d $P4ROOT ] && mkdir $P4ROOT
  $ p4d -f -J off >$P4ROOT/stdout 2>$P4ROOT/stderr &
  $ echo $! >> $DAEMON_PIDS
  $ trap "echo stopping the p4 server ; p4 admin stop" EXIT

  $ # wait for the server to initialize
  $ while ! p4 ; do
  >    sleep 1
  > done >/dev/null 2>/dev/null

create a client spec
  $ P4CLIENT=hg-p4-import; export P4CLIENT
  $ DEPOTPATH=//depot/test-mercurial-import/...
  $ p4 client -o | sed '/^View:/,$ d' >p4client
  $ echo View: >>p4client
  $ echo " $DEPOTPATH //$P4CLIENT/..." >>p4client
  $ p4 client -i <p4client
  Client hg-p4-import saved.

populate the depot
  $ echo a > a
  $ mkdir b
  $ echo c > b/c
  $ p4 add a b/c
  //depot/test-mercurial-import/a#1 - opened for add
  //depot/test-mercurial-import/b/c#1 - opened for add
  $ p4 submit -d initial
  Submitting change 1.
  Locking 2 files ...
  add //depot/test-mercurial-import/a#1
  add //depot/test-mercurial-import/b/c#1
  Change 1 submitted.

change some files
  $ p4 edit a
  //depot/test-mercurial-import/a#1 - opened for edit
  $ echo aa >> a
  $ p4 submit -d "change a"
  Submitting change 2.
  Locking 1 files ...
  edit //depot/test-mercurial-import/a#2
  Change 2 submitted.

  $ p4 edit b/c
  //depot/test-mercurial-import/b/c#1 - opened for edit
  $ echo cc >> b/c
  $ p4 submit -d "change b/c"
  Submitting change 3.
  Locking 1 files ...
  edit //depot/test-mercurial-import/b/c#2
  Change 3 submitted.

convert
  $ hg convert -s p4 $DEPOTPATH dst
  initializing destination dst repository
  reading p4 views
  collecting p4 changelists
  1 initial
  2 change a
  3 change b/c
  scanning source...
  sorting...
  converting...
  2 initial
  1 change a
  0 change b/c
  $ hg -R dst log --template 'rev={rev} desc="{desc}" tags="{tags}" files="{files}"\n'
  rev=2 desc="change b/c" tags="tip" files="b/c"
  rev=1 desc="change a" tags="" files="a"
  rev=0 desc="initial" tags="" files="a b/c"

change some files
  $ p4 edit a b/c
  //depot/test-mercurial-import/a#2 - opened for edit
  //depot/test-mercurial-import/b/c#2 - opened for edit
  $ echo aaa >> a
  $ echo ccc >> b/c
  $ p4 submit -d "change a b/c"
  Submitting change 4.
  Locking 2 files ...
  edit //depot/test-mercurial-import/a#3
  edit //depot/test-mercurial-import/b/c#3
  Change 4 submitted.

convert again
  $ hg convert -s p4 $DEPOTPATH dst
  reading p4 views
  collecting p4 changelists
  1 initial
  2 change a
  3 change b/c
  4 change a b/c
  scanning source...
  sorting...
  converting...
  0 change a b/c
  $ hg -R dst log --template 'rev={rev} desc="{desc}" tags="{tags}" files="{files}"\n'
  rev=3 desc="change a b/c" tags="tip" files="a b/c"
  rev=2 desc="change b/c" tags="" files="b/c"
  rev=1 desc="change a" tags="" files="a"
  rev=0 desc="initial" tags="" files="a b/c"

interesting names
  $ echo dddd > "d d"
  $ mkdir " e"
  $ echo fff >" e/ f"
  $ p4 add "d d" " e/ f"
  //depot/test-mercurial-import/d d#1 - opened for add
  //depot/test-mercurial-import/ e/ f#1 - opened for add
  $ p4 submit -d "add d e f"
  Submitting change 5.
  Locking 2 files ...
  add //depot/test-mercurial-import/ e/ f#1
  add //depot/test-mercurial-import/d d#1
  Change 5 submitted.

convert again
  $ hg convert -s p4 $DEPOTPATH dst
  reading p4 views
  collecting p4 changelists
  1 initial
  2 change a
  3 change b/c
  4 change a b/c
  5 add d e f
  scanning source...
  sorting...
  converting...
  0 add d e f
  $ hg -R dst log --template 'rev={rev} desc="{desc}" tags="{tags}" files="{files}"\n'
  rev=4 desc="add d e f" tags="tip" files=" e/ f d d"
  rev=3 desc="change a b/c" tags="" files="a b/c"
  rev=2 desc="change b/c" tags="" files="b/c"
  rev=1 desc="change a" tags="" files="a"
  rev=0 desc="initial" tags="" files="a b/c"

exit trap:
  stopping the p4 server