[gnome-continuous-yocto/gnomeostree-3.28-rocko: 3185/8267] bitbake: siggen: Pass basehash to worker processes and sanity check reparsing result

[Emmanuele Bassi <ebassi src gnome org>]

commit 0a4a6d6956a10aa0a6589de12b0b2380a9f0a7d9
Author: Richard Purdie <richard purdie linuxfoundation org>
Date:   Wed Nov 2 15:06:50 2016 +0000

    bitbake: siggen: Pass basehash to worker processes and sanity check reparsing result
    
    Bitbake can parse metadata in the cooker and in the worker during builds. If
    the metadata isn't deterministic, it can change between these two parses and
    this confuses things a lot. It turns out to be hard to debug these issues
    currently.
    
    This patch ensures the basehashes from the original parsing are passed into
    the workers and that these are checked when reparsing for consistency. The user
    is shown an error message if inconsistencies are found.
    
    There is debug code in siggen.py (see the "Slow but can be useful for debugging
    mismatched basehashes" commented code), we don't enable this by default due to
    performance issues. If you run into this message, enable this code and you will
    find "sigbasedata" files in tmp/stamps which should correspond to the hashes
    shown in this error message. bitbake-diffsigs on the files should show which
    variables are changing.
    
    (Bitbake rev: 857829048c14338132784326ba98a71f12192db8)
    
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 bitbake/lib/bb/siggen.py |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)
---
diff --git a/bitbake/lib/bb/siggen.py b/bitbake/lib/bb/siggen.py
index 3a7dac4..9485bf5 100644
--- a/bitbake/lib/bb/siggen.py
+++ b/bitbake/lib/bb/siggen.py
@@ -30,6 +30,7 @@ class SignatureGenerator(object):
     name = "noop"
 
     def __init__(self, data):
+        self.basehash = {}
         self.taskhash = {}
         self.runtaskdeps = {}
         self.file_checksum_values = {}
@@ -61,11 +62,10 @@ class SignatureGenerator(object):
         return
 
     def get_taskdata(self):
-       return (self.runtaskdeps, self.taskhash, self.file_checksum_values, self.taints)
+        return (self.runtaskdeps, self.taskhash, self.file_checksum_values, self.taints, self.basehash)
 
     def set_taskdata(self, data):
-        self.runtaskdeps, self.taskhash, self.file_checksum_values, self.taints = data
-
+        self.runtaskdeps, self.taskhash, self.file_checksum_values, self.taints, self.basehash = data
 
 class SignatureGeneratorBasic(SignatureGenerator):
     """
@@ -133,7 +133,11 @@ class SignatureGeneratorBasic(SignatureGenerator):
                 var = lookupcache[dep]
                 if var is not None:
                     data = data + str(var)
-            self.basehash[fn + "." + task] = hashlib.md5(data.encode("utf-8")).hexdigest()
+            datahash = hashlib.md5(data.encode("utf-8")).hexdigest()
+            k = fn + "." + task
+            if k in self.basehash and self.basehash[k] != datahash:
+                bb.error("When reparsing %s, the basehash value changed from %s to %s. The metadata is not 
deterministic and this needs to be fixed." % (k, self.basehash[k], datahash))
+            self.basehash[k] = datahash
             taskdeps[task] = alldeps
 
         self.taskdeps[fn] = taskdeps
@@ -182,6 +186,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
     def get_taskhash(self, fn, task, deps, dataCache):
         k = fn + "." + task
         data = dataCache.basetaskhash[k]
+        self.basehash[k] = data
         self.runtaskdeps[k] = []
         self.file_checksum_values[k] = []
         recipename = dataCache.pkg_fn[fn]