# HG changeset patch
# User julien tayon <julien.tayon@logilab.fr>
# Date 1560238812 -7200
# Node ID de1c0721656e72bfc4fdcf3c1a3ab40895801d2e
# Parent  619210ba8b5e5a72f1a282aa28fb4523bda21510
Fix sorting key for rdefs in schema viewer

With changeset 234ca3cbbb46, clicking in the schema of an entity with
cubicweb in py3 on "vue en boite" will probably result in an infinite
spinner (which implies cw > 3.26)

What happened ?

This "vue en boite" used to work at least until...

hg diff -c a8c1ea390400 cubicweb/schema.py


    @@ -993,10 +992,6 @@ class CubicWebRelationSchema(PermissionM
                         return False
             return True

    -    @deprecated('use .rdef(subjtype, objtype).role_cardinality(role)')
    -    def cardinality(self, subjtype, objtype, target):
    -        return self.rdef(subjtype, objtype).role_cardinality(target)
    -

     class CubicWebSchema(Schema):
         """set of entities and relations schema defining the possible data sets


But, wait ...
If I open a shell on an instance of cw 3.24 something seems off

>>> list(schema['CWUniqueTogetherConstraint'].relation_definitions())[0][0].cardinality
# <bound method CubicWebRelationSchema.wrapped of <constraint_of [CWUniqueTogetherConstraint,CWEType]>>

We have been sorting on a method the whole time ? Is it possible what
were the effects ?

1) We cannot sort function can't we ?

>>> def adder(i): return lambda x: x+i
>>> sorted(map(adder,range(10)))
[<function __main__.<lambda>>,
 <function __main__.<lambda>>,
...

Yes we can.

2) what does it means.

>>> { adder(1) : 1 }
Out[19]: {<function __main__.<lambda>>: 1}

In fact the function object as a __hash__ method (which is practical for making
memoizers (cache)), and return truly random results (pseudo random).

My take on this patch is relations have NEVER been sorted by cardinality.
No one never ever noticed. Hence, I propose to not fix a bug that never was
reported.

diff -r 619210ba8b5e -r de1c0721656e cubicweb/web/schemaviewer.py
--- a/cubicweb/web/schemaviewer.py	Tue Jun 04 09:35:47 2019 +0200
+++ b/cubicweb/web/schemaviewer.py	Tue Jun 11 09:40:12 2019 +0200
@@ -140,7 +140,7 @@
         first = True
 
         rel_defs = sorted(eschema.relation_definitions(),
-                          key=lambda el: (el[0].type, el[0].cardinality))
+                          key=lambda el: el[0].type)
 
         for rschema, targetschemas, role in rel_defs:
             if rschema.type in skiptypes: