[yocto] SRC URI checksums

[Edward Wingate]

I have a recipe that has a SRC_URI retrieving from a mercurial repo:
SRC_URI = "hg://server/project;module=name;rev=tip"
SRC_URI[md5sum] = "xxx"
SRC_URI[sha256sum] = "yyy"

I changed the SRC_URL to retreive from a specific revision instead of tip:
SRC_URI = "hg://server/project;module=name;rev=1234567890"

I went ahead and did a bitbake, expecting it to complain about the
SRC_URI checksums not matching, and I would go ahead and update the
checksums from the error output.

But it succeeded, building with the correct revision.  I thought the
SRC_URI checksums had to be updated when the SRC_URI changes?

Ed