Merge lp:~cjwatson/lazr.restful/py3-fix-bytes-modification-detection into lp:lazr.restful

[Colin Watson]

Fix detection of Bytes field modifications on Python 3.

[Thiago F. Pappacena (pappacena)]

LGTM

review: Approve

=== modified file 'src/lazr/restful/_resource.py'
--- src/lazr/restful/_resource.py	2020-09-24 10:01:25 +0000
+++ src/lazr/restful/_resource.py	2021-01-21 00:06:16 +0000
@@ -1117,9 +1117,13 @@
 
             if IBytes.providedBy(field):
                 # We don't modify Bytes fields from the Entry that contains
-                # them, but we may tell users how to do so if they attempt to
-                # change them.
-                if value != current_value:
+                # them, but we may tell users how to do so if they attempt
+                # to change them.  The encode call is because
+                # BytesFieldMarshaller.unmarshall returns a link to the byte
+                # storage resource as a str, but
+                # BytesFieldMarshaller.marshall_from_json_data returns
+                # bytes.
+                if value != current_value.encode('UTF-8'):
                     if field.readonly:
                         errors.append(modified_read_only_attribute
                                       % repr_name)