[oe] rm_work.bbclass causes the incremental building impossible

[Guo Hongruan]

Hi guys,
   I want to do incremental building when openembedded recipe changes. But  
I found that when adding INHERIT += "rm_work" in local.conf, bitbake  
always building lots of packages which recipes never were changed. I  
verified it with the newest openembedded  
667b7cb389a4cd8677fe5272f16c0d31bd77a4da


After adding INHERIT += "rm_work", the second building will delete lots of  
stamps files. I don't know why.
camelguo at guohr-laptop-ubuntu:/opt/workdir/oe/build/gulessoft-oe-standard-conf$  
bitbake shasum-native
NOTE: Handling BitBake files: - (7967/7967) [100 %]
NOTE: Parsing finished. 7327 cached, 311 parsed, 329 skipped, 0 masked.
NOTE: oestats: build 52017
NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing runqueue
NOTE: Removing stamps:  
/media/work-disk/workdir/allinone-test/stamps/i686-linux/shasum-native-1.0-r1.*
NOTE: Running task 1 of 65 (ID: 1,  
/opt/workdir/oe/openembedded/recipes/shasum/shasum-native.bb, do_setscene)
NOTE: Running task 2 of 65 (ID: 2,  
/opt/workdir/oe/openembedded/recipes/shasum/shasum-native.bb, do_fetch)
NOTE: Running task 3 of 65 (ID: 4,  
/opt/workdir/oe/openembedded/recipes/shasum/shasum-native.bb, do_unpack)

Without INHERIT += "rm_work", the second building will delete nothing,  
which is what I expected.
camelguo at guohr-laptop-ubuntu:/opt/workdir/oe/build/gulessoft-oe-standard-conf$  
bitbake shasum-native
NOTE: Handling BitBake files: - (7967/7967) [100 %]
NOTE: Parsing finished. 7327 cached, 311 parsed, 329 skipped, 0 masked.
NOTE: oestats: build 52008
NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing runqueue
NOTE: Tasks Summary: Attempted 15 tasks of which 15 didn't need to be  
rerun and 0 failed.

Any advice is welcome.

Thanks a lot!


-- 
Guo Hongruan, Embedded Linux Consultant
Skype: camelguo
Twitter: camelguo
http://www.gulessoft.com