filelog: wrap revlog instead of inheriting it (API)
The revlog base class exposes a ton of methods. Inheriting the
revlog class for filelog will make it difficult to expose a
clean interface. There will be abstraction violations.
This commit breaks the inheritance of revlog by the filelog
class. Filelog instances now contain a reference to a revlog
instance. Various properties and methods are now proxied to
that instance.
There is precedence for doing this: manifestlog does something
similar. Although, manifestlog has a cleaner interface than
filelog. We'll get there with filelog...
The new filelog class exposes a handful of extra properties and
methods that aren't part of the declared filelog interface.
Every extra item was added in order to get a test to pass. The
set of tests that failed without these extra proxies has
significant overlap with the set of tests that don't work with
the simple store repo. There should be no surprise there.
Hopefully the hardest part about this commit to review are the
changes to bundlerepo and unionrepo. Both repository types
define a custom revlog or revlog-like class and then have a
custom filelog that inherits from both filelog and their custom
revlog. This code has been changed so the filelog types don't
inherit from revlog. Instead, they replace the revlog instance
on the created filelog. This is super hacky. I plan to fix this
in a future commit by parameterizing filelog.__init__.
Because Python function call overhead is a thing, this change
could impact performance by introducing a nearly empty proxy
function for various methods and properties. I would gladly
measure the performance impact of it, but I'm not sure what
operations have tight loops over filelog attribute lookups
or function calls. I know some of the DAG traversal code can
be sensitive about the performance of e.g. parentrevs(). However,
many of these functions are implemented on the revlog class and
therefore have direct access to self.parentrevs() and aren't
going through a proxy.
.. api::
filelog.filelog is now a standalone class and doesn't inherit
from revlog. Instead, it wraps a revlog instance at self._revlog.
This change was made in an attempt to formalize storage APIs and
prevent revlog implementation details leaking through to callers.
Differential Revision: https://phab.mercurial-scm.org/D3154
Set vars:
$ CONTRIBDIR="$TESTDIR/../contrib"
Test simplemerge command:
$ cp "$CONTRIBDIR/simplemerge" .
$ echo base > base
$ echo local > local
$ cat base >> local
$ cp local orig
$ cat base > other
$ echo other >> other
changing local directly
$ $PYTHON simplemerge local base other && echo "merge succeeded"
merge succeeded
$ cat local
local
base
other
$ cp orig local
printing to stdout
$ $PYTHON simplemerge -p local base other
local
base
other
local:
$ cat local
local
base
conflicts
$ cp base conflict-local
$ cp other conflict-other
$ echo not other >> conflict-local
$ echo end >> conflict-local
$ echo end >> conflict-other
$ $PYTHON simplemerge -p conflict-local base conflict-other
base
<<<<<<< conflict-local
not other
=======
other
>>>>>>> conflict-other
end
[1]
1 label
$ $PYTHON simplemerge -p -L foo conflict-local base conflict-other
base
<<<<<<< foo
not other
=======
other
>>>>>>> conflict-other
end
[1]
2 labels
$ $PYTHON simplemerge -p -L foo -L bar conflict-local base conflict-other
base
<<<<<<< foo
not other
=======
other
>>>>>>> bar
end
[1]
3 labels
$ $PYTHON simplemerge -p -L foo -L bar -L base conflict-local base conflict-other
base
<<<<<<< foo
not other
end
||||||| base
=======
other
end
>>>>>>> bar
[1]
too many labels
$ $PYTHON simplemerge -p -L foo -L bar -L baz -L buz conflict-local base conflict-other
abort: can only specify three labels.
[255]
binary file
$ $PYTHON -c "f = open('binary-local', 'w'); f.write('\x00'); f.close()"
$ cat orig >> binary-local
$ $PYTHON simplemerge -p binary-local base other
warning: binary-local looks like a binary file.
[1]
binary file --text
$ $PYTHON simplemerge -a -p binary-local base other 2>&1
warning: binary-local looks like a binary file.
\x00local (esc)
base
other
help
$ $PYTHON simplemerge --help
simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
options:
-L --label labels to use on conflict markers
-a --text treat all files as text
-p --print print results instead of overwriting LOCAL
--no-minimal no effect (DEPRECATED)
-h --help display help and exit
-q --quiet suppress output
wrong number of arguments
$ $PYTHON simplemerge
simplemerge: wrong number of arguments
simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
options:
-L --label labels to use on conflict markers
-a --text treat all files as text
-p --print print results instead of overwriting LOCAL
--no-minimal no effect (DEPRECATED)
-h --help display help and exit
-q --quiet suppress output
[1]
bad option
$ $PYTHON simplemerge --foo -p local base other
simplemerge: option --foo not recognized
simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
options:
-L --label labels to use on conflict markers
-a --text treat all files as text
-p --print print results instead of overwriting LOCAL
--no-minimal no effect (DEPRECATED)
-h --help display help and exit
-q --quiet suppress output
[1]