bitbake: build: Add clean_stamp API function to allow removal of task stamps

We currently have no API to be able to remove all the potential stamps of a
task. It is unusual to need to do this, particularly as you could race against
other things happening in the system but we do have a use case for this in
cleaning up sysroots in OE-Core. The alternative is to mess with CLEANMASK in
OE-Core but that is just going to add potential for errors.

We need the first part of the make_stamp() function so separate that out so
it can be called seperately.

(Bitbake rev: 494fcfcb7c4469915c67f544997104d81c417266)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 4d671504a25863018ac51c21c005cef0a4d8f05c)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/build.py

@@ -835,11 +835,7 @@ def stamp_cleanmask_internal(taskname, d, file_name):
 
     return [cleanmask, cleanmask.replace(taskflagname, taskflagname + "_setscene")]
 
-def make_stamp(task, d, file_name = None):
+def clean_stamp(task, d, file_name = None):
-    """
-    Creates/updates a stamp for a given task
-    (d can be a data dict or dataCache)
-    """
     cleanmask = stamp_cleanmask_internal(task, d, file_name)
     for mask in cleanmask:
         for name in glob.glob(mask):
@@ -850,6 +846,14 @@ def make_stamp(task, d, file_name = None):
             if name.endswith('.taint'):
                 continue
             os.unlink(name)
+    return
+
+def make_stamp(task, d, file_name = None):
+    """
+    Creates/updates a stamp for a given task
+    (d can be a data dict or dataCache)
+    """
+    clean_stamp(task, d, file_name)
 
     stamp = stamp_internal(task, d, file_name)
     # Remove the file and recreate to force timestamp