filemerge: use arbitraryfilectx for backups
With in-memory merge, backup files might be overlayworkingfilectxs stored
in memory. But they could also be real files if the user's backup directory is
outside the working dir.
Rather than have two code paths everywhere, let's use arbitraryfilectx so they
can be consistent.
Differential Revision: https://phab.mercurial-scm.org/D1057
A new repository uses zlib storage, which doesn't need a requirement
$ hg init default
$ cd default
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
$ touch foo
$ hg -q commit -A -m 'initial commit with a lot of repeated repeated repeated text to trigger compression'
$ hg debugrevlog -c | grep 0x78
0x78 (x) : 1 (100.00%)
0x78 (x) : 110 (100.00%)
$ cd ..
Unknown compression engine to format.compression aborts
$ hg --config experimental.format.compression=unknown init unknown
abort: compression engine unknown defined by experimental.format.compression not available
(run "hg debuginstall" to list available compression engines)
[255]
A requirement specifying an unknown compression engine results in bail
$ hg init unknownrequirement
$ cd unknownrequirement
$ echo exp-compression-unknown >> .hg/requires
$ hg log
abort: repository requires features unknown to this Mercurial: exp-compression-unknown!
(see https://mercurial-scm.org/wiki/MissingRequirement for more information)
[255]
$ cd ..
#if zstd
$ hg --config experimental.format.compression=zstd init zstd
$ cd zstd
$ cat .hg/requires
dotencode
exp-compression-zstd
fncache
generaldelta
revlogv1
store
$ touch foo
$ hg -q commit -A -m 'initial commit with a lot of repeated repeated repeated text'
$ hg debugrevlog -c | grep 0x28
0x28 : 1 (100.00%)
0x28 : 98 (100.00%)
$ cd ..
Specifying a new format.compression on an existing repo won't introduce data
with that engine or a requirement
$ cd default
$ touch bar
$ hg --config experimental.format.compression=zstd -q commit -A -m 'add bar with a lot of repeated repeated repeated text'
$ cat .hg/requires
dotencode
fncache
generaldelta
revlogv1
store
$ hg debugrevlog -c | grep 0x78
0x78 (x) : 2 (100.00%)
0x78 (x) : 199 (100.00%)
#endif