debugindex: add --format flag to allow debugging parentdelta
-f 1 shows extra data from revlogv1 (aka revlogng) including flags and size
(based on a patch by Pradeepkumar Gayam <in3xes@gmail.com>)
$ hg init outer
$ cd outer
hg debugsub with no remapping
$ echo 'sub = http://example.net/libfoo' > .hgsub
$ hg add .hgsub
$ hg debugsub
path sub
source http://example.net/libfoo
revision
hg debugsub with remapping
$ echo '[subpaths]' > .hg/hgrc
$ printf 'http://example.net/lib(.*) = C:\\libs\\\\1-lib\\\n' >> .hg/hgrc
$ hg debugsub
path sub
source C:\libs\foo-lib\
revision
test bad subpaths pattern
$ cat > .hg/hgrc <<EOF
> [subpaths]
> .* = \1
> EOF
$ hg debugsub
abort: bad subrepository pattern in $TESTTMP/outer/.hg/hgrc:2: invalid group reference
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