Correct optimization from 3464f5e77f34; add a test.
If there are two (or more) heads that point to the same .hgtags
node, we can safely skip parsing the file in all but the last head.
(In 3464f5e77f34, we were parsing the file in the first head and
skipping all the others.)
#!/bin/sh
hg init a
cd a
echo a > a
hg ci -Ama -d '1 0'
hg cp a b
hg ci -mb -d '2 0'
mkdir dir
hg mv b dir
hg ci -mc -d '3 0'
hg mv a b
hg ci -md -d '4 0'
hg mv dir/b e
hg ci -me -d '5 0'
hg log a
echo % -f, directory
hg log -f dir
echo % -f, but no args
hg log -f
echo % one rename
hg log -vf a
echo % many renames
hg log -vf e
echo % log copies
hg log -vC --template '{rev} {file_copies%filecopy}\n'
echo % log copies, non-linear manifest
hg up -C 3
hg mv dir/b e
echo foo > foo
hg ci -Ame2 -d '6 0'
hg log -vC --template '{rev} {file_copies%filecopy}\n' -r 5
# log --follow tests
hg init ../follow
cd ../follow
echo base > base
hg ci -Ambase -d '1 0'
echo r1 >> base
hg ci -Amr1 -d '1 0'
echo r2 >> base
hg ci -Amr2 -d '1 0'
hg up -C 1
echo b1 > b1
hg ci -Amb1 -d '1 0'
echo % log -f
hg log -f
hg up -C 0
echo b2 > b2
hg ci -Amb2 -d '1 0'
echo % log -f -r 1:tip
hg log -f -r 1:tip
hg up -C 3
hg merge tip
hg ci -mm12 -d '1 0'
echo postm >> b1
hg ci -Amb1.1 -d'1 0'
echo % log --follow-first
hg log --follow-first
echo % log -P 2
hg log -P 2