use 'x is None' instead of 'x == None'
The built-in None object is a singleton and it is therefore safe to
compare memory addresses with is. It is also faster, how much depends
on the object being compared. For a simple type like str I get:
| s = "foo" | s = None
----------+-----------+----------
s == None | 0.25 usec | 0.21 usec
s is None | 0.17 usec | 0.17 usec
#!/bin/sh
branchcache=.hg/branchheads.cache
hg init t
cd t
hg branches
echo foo > a
hg add a
hg ci -m "initial" -d "1000000 0"
hg branch foo
hg branch
hg ci -m "add branch name" -d "1000000 0"
hg branch bar
hg ci -m "change branch name" -d "1000000 0"
echo % branch shadowing
hg branch default
hg branch -f default
hg ci -m "clear branch name" -d "1000000 0"
hg co foo
hg branch
echo bleah > a
hg ci -m "modify a branch" -d "1000000 0"
hg merge default
hg branch
hg ci -m "merge" -d "1000000 0"
hg log
hg branches
hg branches -q
echo % test for invalid branch cache
hg rollback
cp $branchcache .hg/bc-invalid
hg log -r foo
cp .hg/bc-invalid $branchcache
hg --debug log -r foo
rm $branchcache
echo corrupted > $branchcache
hg log -qr foo
cat $branchcache
echo % push should update the branch cache
hg init ../target
echo % pushing just rev 0
hg push -qr 0 ../target
cat ../target/$branchcache
echo % pushing everything
hg push -qf ../target
cat ../target/$branchcache
echo % update with no arguments: tipmost revision of the current branch
hg up -q -C 0
hg up -q
hg id
hg up -q 1
hg up -q
hg id
hg branch foobar
hg up
echo % fastforward merge
hg branch ff
echo ff > ff
hg ci -Am'fast forward' -d '1000000 0'
hg up foo
hg merge ff
hg branch
hg commit -m'Merge ff into foo' -d '1000000 0'
hg parents
hg manifest
echo % test merging, add 3 default heads and one test head
cd ..
hg init merges
cd merges
echo a > a
hg ci -Ama
echo b > b
hg ci -Amb
hg up 0
echo c > c
hg ci -Amc
hg up 0
echo d > d
hg ci -Amd
hg up 0
hg branch test
echo e >> e
hg ci -Ame
hg log
echo % implicit merge with test branch as parent
hg merge
hg up -C default
echo % implicit merge with default branch as parent
hg merge
echo % 3 branch heads, explicit merge required
hg merge 2
hg ci -m merge
echo % 2 branch heads, implicit merge works
hg merge