tests/test-fetch

revlog: break up compression of large deltas

Python's zlib apparently makes an internal copy of strings passed to
compress(). To avoid this, compress strings 1M at a time, then join
them at the end if the result would be smaller than the original.

For initial commits of large but compressible files, this cuts peak
memory usage nearly in half.

#!/bin/sh

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

hg init a
echo a > a/a
hg --cwd a commit -d '1 0' -Ama

hg clone a b
hg clone a c

echo b > a/b
hg --cwd a commit -d '2 0' -Amb
hg --cwd a parents -q

echo % should pull one change
hg --cwd b fetch ../a
hg --cwd b parents -q

echo c > c/c
hg --cwd c commit -d '3 0' -Amc
hg --cwd c fetch -d '4 0' -m 'automated merge' ../a
ls c