view tests/test-chg.t @ 30745:c1b7b2285522

revlog: flag processor

Add the ability for revlog objects to process revision flags and apply
registered transforms on read/write operations.

This patch introduces:
- the 'revlog._processflags()' method that looks at revision flags and applies
  flag processors registered on them. Due to the need to handle non-commutative
  operations, flag transforms are applied in stable order but the order in which
  the transforms are applied is reversed between read and write operations.
- the 'addflagprocessor()' method allowing to register processors on flags.
  Flag processors are defined as a 3-tuple of (read, write, raw) functions to be
  applied depending on the operation being performed.
- an update on 'revlog.addrevision()' behavior. The current flagprocessor design
  relies on extensions to wrap around 'addrevision()' to set flags on revision
  data, and on the flagprocessor to perform the actual transformation of its
  contents. In the lfs case, this means we need to process flags before we meet
  the 2GB size check, leading to performing some operations before it happens:
  - if flags are set on the revision data, we assume some extensions might be
    modifying the contents using the flag processor next, and we compute the
    node for the original revision data (still allowing extension to override
    the node by wrapping around 'addrevision()').
  - we then invoke the flag processor to apply registered transforms (in lfs's
    case, drastically reducing the size of large blobs).
  - finally, we proceed with the 2GB size check.

Note: In the case a cachedelta is passed to 'addrevision()' and we detect the
flag processor modified the revision data, we chose to trust the flag processor
and drop the cachedelta.

#require chg

  $ cp $HGRCPATH $HGRCPATH.orig

init repo

  $ chg init foo
  $ cd foo

ill-formed config

  $ chg status
  $ echo '=brokenconfig' >> $HGRCPATH
  $ chg status
  hg: parse error at * (glob)
  [255]

  $ cp $HGRCPATH.orig $HGRCPATH

long socket path

  $ sockpath=$TESTTMP/this/path/should/be/longer/than/one-hundred-and-seven/characters/where/107/is/the/typical/size/limit/of/unix-domain-socket
  $ mkdir -p $sockpath
  $ bakchgsockname=$CHGSOCKNAME
  $ CHGSOCKNAME=$sockpath/server
  $ export CHGSOCKNAME
  $ chg root
  $TESTTMP/foo
  $ rm -rf $sockpath
  $ CHGSOCKNAME=$bakchgsockname
  $ export CHGSOCKNAME

  $ cd ..

server lifecycle
----------------

chg server should be restarted on code change, and old server will shut down
automatically. In this test, we use the following time parameters:

 - "sleep 1" to make mtime different
 - "sleep 2" to notice mtime change (polling interval is 1 sec)

set up repository with an extension:

  $ chg init extreload
  $ cd extreload
  $ touch dummyext.py
  $ cat <<EOF >> .hg/hgrc
  > [extensions]
  > dummyext = dummyext.py
  > EOF

isolate socket directory for stable result:

  $ OLDCHGSOCKNAME=$CHGSOCKNAME
  $ mkdir chgsock
  $ CHGSOCKNAME=`pwd`/chgsock/server

warm up server:

  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

new server should be started if extension modified:

  $ sleep 1
  $ touch dummyext.py
  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: instruction: unlink $TESTTMP/extreload/chgsock/server-* (glob)
  chg: debug: instruction: reconnect
  chg: debug: start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

old server will shut down, while new server should still be reachable:

  $ sleep 2
  $ CHGDEBUG= chg log 2>&1 | (egrep 'instruction|start' || true)

socket file should never be unlinked by old server:
(simulates unowned socket by updating mtime, which makes sure server exits
at polling cycle)

  $ ls chgsock/server-*
  chgsock/server-* (glob)
  $ touch chgsock/server-*
  $ sleep 2
  $ ls chgsock/server-*
  chgsock/server-* (glob)

since no server is reachable from socket file, new server should be started:
(this test makes sure that old server shut down automatically)

  $ CHGDEBUG= chg log 2>&1 | egrep 'instruction|start'
  chg: debug: start cmdserver at $TESTTMP/extreload/chgsock/server.* (glob)

shut down servers and restore environment:

  $ rm -R chgsock
  $ CHGSOCKNAME=$OLDCHGSOCKNAME
  $ cd ..