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
echo '% Show all commands except debug commands'
hg debugcomplete
echo
echo '% Show all commands that start with "a"'
hg debugcomplete a
echo
echo '% Do not show debug commands if there are other candidates'
hg debugcomplete d
echo
echo '% Show debug commands if there are no other candidates'
hg debugcomplete debug
echo
echo '% Do not show the alias of a debug command if there are other candidates'
echo '% (this should hide rawcommit)'
hg debugcomplete r
echo
echo '% Show the alias of a debug command if there are no other candidates'
hg debugcomplete rawc
echo
echo '% Show the global options'
hg debugcomplete --options | sort
echo
echo '% Show the options for the "serve" command'
hg debugcomplete --options serve | sort
echo
echo '% Show an error if we use --options with an ambiguous abbreviation'
hg debugcomplete --options s
exit 0