[OE-core] Quick question about OE-core/bitbake's re-building

[Burton, Ross]

On 5 May 2014 01:34, Joel Fernandes <joelf at ti.com> wrote:
> However one thing, is the updates don't happen if you revert the changes
> back to what it used to be in an earlier revision.
>
> For example if I make changes such that task hash is now X
> Then I build, and its called r0.0.
> Then I make some more changes such that the hash is now Y
> And it becomes r0.1.
>
> Then after some more changes, it becomes X. Now instead of rebuilding
> and calling it r0.2, the rebuild doesn't happen. I wonder if this is the
> right thing, or the updates should continue to roll.

So the hash that Joel refers to is used as a key in the "sstate
cache", and the build packages are cached in there.  When you revert
the package back to X instead of having to do a rebuild, it can simply
extract the relevant file from the cache.

(you can verify this by reading the cooker log of the build)

Ross