nodemap: introduce append-only incremental update of the persistent data
Rewriting the full nodemap for each transaction has a cost we would like to
avoid. We introduce a new way to write persistent nodemap data by adding new
information at the end for file. Any new and updated block as added at the end
of the file. The last block is the new root node.
With this method, some of the block already on disk get "dereferenced" and
become dead data. In later changesets, We'll start tracking the amount of dead
data to eventually re-generate a full nodemap.
Differential Revision: https://phab.mercurial-scm.org/D7886
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]