On rare occasions, you may find yourself debugging a task dependency problem, for example, if BitBake misses a task dependency.

In the tmp/stamps sub-directory inside the build directory, you can find two file types that are helpful when debugging dependency problems:

• sigdata, a Python database of all the metadata that is used to calculate the task's input checksum
• siginfo, which is the same but for shared state cache accelerated recipes

You can use bitbake-dumpsig on both of these file types to dump the variable dependencies for the task, variable values, as well as a list of variables never included in any checksum.

When trying to compare two versions of a given task, bitbake-diffsig can be used to dump the differences between two sigdata or siginfo revisions.