bitbake: data/siggen: Don't expand ignored variables

If a variable is in the signature whitelist, we'd currently expand
it, then later ignore the data. This is problemtic for code which
has effects when expanded, recently source date epoch in OE-Core
for example.

We don't actually need to do this, if we pass the whitelist into
the earlier function it can avoid the expansion. This also also
give a small performance boost since we avoid running code in some
cases.

[YOCTO #13581]

(Bitbake rev: f483ee4a869fb1dafbe4bdf2da228cdaa40b38bd)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/data.py

@@ -365,7 +365,7 @@ def build_dependencies(key, keys, shelldeps, varflagsexcl, d):
     #bb.note("Variable %s references %s and calls %s" % (key, str(deps), str(execs)))
     #d.setVarFlag(key, "vardeps", deps)
 
-def generate_dependencies(d):
+def generate_dependencies(d, whitelist):
 
     keys = set(key for key in d if not key.startswith("__"))
     shelldeps = set(key for key in d.getVar("__exportlist", False) if d.getVarFlag(key, "export", False) and not d.getVarFlag(key, "unexport", False))
@@ -380,7 +380,7 @@ def generate_dependencies(d):
         newdeps = deps[task]
         seen = set()
         while newdeps:
-            nextdeps = newdeps
+            nextdeps = newdeps - whitelist
             seen |= nextdeps
             newdeps = set()
             for dep in nextdeps:

bitbake/lib/bb/siggen.py

@@ -146,7 +146,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
     def _build_data(self, fn, d):
 
         ignore_mismatch = ((d.getVar("BB_HASH_IGNORE_MISMATCH") or '') == '1')
-        tasklist, gendeps, lookupcache = bb.data.generate_dependencies(d)
+        tasklist, gendeps, lookupcache = bb.data.generate_dependencies(d, self.basewhitelist)
 
         taskdeps, basehash = bb.data.generate_dependency_hash(tasklist, gendeps, lookupcache, self.basewhitelist, fn)
 

bitbake/lib/bb/tests/data.py

@@ -476,7 +476,7 @@ class Contains(unittest.TestCase):
 class TaskHash(unittest.TestCase):
     def test_taskhashes(self):
         def gettask_bashhash(taskname, d):
-            tasklist, gendeps, lookupcache = bb.data.generate_dependencies(d)
+            tasklist, gendeps, lookupcache = bb.data.generate_dependencies(d, set())
             taskdeps, basehash = bb.data.generate_dependency_hash(tasklist, gendeps, lookupcache, set(), "somefile")
             bb.warn(str(lookupcache))
             return basehash["somefile:" + taskname]