Using local git repo for recipe development

[Patrick Voelker]

I'm creating a new recipe for local development but when I do a 'devtool modify <recipe>' it always seems to make an empty directory (that contains only .git.) 

Here's the relevant lines from my .bb file:
SRC_URI = "git:///home/pvoelker/bmc/dev/oem;protocol=file"
SRCREV = "4db17f482b0bdcdcf5658c7d323cc563eb78556a"
inherit autotools

Here's the warning from 'devtool modify':
WARNING: No source unpacked to S - either the phoenix-oem recipe doesn't use any source or the correct source directory could not be determined

If I change either the SRC_URI or the SRCREV to be invalid, I get an error instead of a warning so it's definitely finding the local repo.

I can't figure out why none of the files in my commit are making it into the unpack directory.  Any ideas or tips on debugging?  I also tried using  a .tar.gz file instead of a local git repo and had the same result.