revlog: fix revlogio.packentry corner case We want to store version information about the revlog in the first entry of its index. The code in packentry was using some heuristics to detect whether this was the first entry, but these heuristics could fail in some cases (e.g. rev 0 was empty; rev 1 descends directly from the nullid and is stored as a delta). We now give the revision number to packentry to avoid heuristics.

#!/bin/sh

hg init repo
cd repo
echo foo > foo
hg ci -qAm 'add foo' -d '0 0'
echo >> foo
hg ci -m 'change foo' -d '0 0'
hg up -qC 0
echo bar > bar
hg ci -qAm 'add bar' -d '0 0'
hg log
cd ..
hg init copy
cd copy

echo '% pull -r 0'
hg pull -qr 0 ../repo
hg log

echo '% pull -r 1'
hg pull -qr 1 ../repo
hg log

# this used to abort: received changelog group is empty
echo '% pull -r 1 again'
hg pull -qr 1 ../repo