--- a/cubicweb/server/schemaserial.py	Fri Apr 05 17:21:14 2019 +0200
+++ b/cubicweb/server/schemaserial.py	Fri Apr 05 17:58:19 2019 +0200
@@ -17,14 +17,10 @@
 # with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
 """functions for schema / permissions (de)serialization using RQL"""
 
-from __future__ import print_function
-
 import json
 import sys
 import sqlite3
 
-from six import PY2, text_type, string_types
-
 from logilab.common.shellutils import ProgressBar, DummyProgressBar
 
 from yams import BadSchemaDefinition, schema as schemamod, buildobjs as ybo, constraints
@@ -378,7 +374,7 @@
     cstrtypemap = {}
     rql = 'INSERT CWConstraintType X: X name %(ct)s'
     for cstrtype in CONSTRAINTS:
-        cstrtypemap[cstrtype] = execute(rql, {'ct': text_type(cstrtype)},
+        cstrtypemap[cstrtype] = execute(rql, {'ct': cstrtype},
                                         build_descr=False)[0][0]
         pb.update()
     # serialize relations
@@ -483,7 +479,7 @@
     for i, name in enumerate(unique_together):
         rschema = eschema.schema.rschema(name)
         rtype = 'T%d' % i
-        substs[rtype] = text_type(rschema.type)
+        substs[rtype] = rschema.type
         relations.append('C relations %s' % rtype)
         restrictions.append('%(rtype)s name %%(%(rtype)s)s' % {'rtype': rtype})
     relations = ', '.join(relations)
@@ -494,18 +490,10 @@
 
 
 def _ervalues(erschema):
-    try:
-        type_ = text_type(erschema.type)
-    except UnicodeDecodeError as e:
-        raise Exception("can't decode %s [was %s]" % (erschema.type, e))
-    try:
-        desc = text_type(erschema.description) or u''
-    except UnicodeDecodeError as e:
-        raise Exception("can't decode %s [was %s]" % (erschema.description, e))
     return {
-        'name': type_,
+        'name': erschema.type,
         'final': erschema.final,
-        'description': desc,
+        'description': erschema.description,
         }
 
 # rtype serialization
@@ -531,10 +519,7 @@
     values['final'] = rschema.final
     values['symmetric'] = rschema.symmetric
     values['inlined'] = rschema.inlined
-    if PY2 and isinstance(rschema.fulltext_container, str):
-        values['fulltext_container'] = unicode(rschema.fulltext_container)
-    else:
-        values['fulltext_container'] = rschema.fulltext_container
+    values['fulltext_container'] = rschema.fulltext_container
     relations = ['X %s %%(%s)s' % (attr, attr) for attr in sorted(values)]
     return relations, values
 
@@ -547,7 +532,7 @@
 
 def crschema_relations_values(crschema):
     values = _ervalues(crschema)
-    values['rule'] = text_type(crschema.rule)
+    values['rule'] = crschema.rule
     # XXX why oh why?
     del values['final']
     relations = ['X %s %%(%s)s' % (attr, attr) for attr in sorted(values)]
@@ -593,8 +578,6 @@
             value = bool(value)
         elif prop == 'ordernum':
             value = int(value)
-        elif PY2 and isinstance(value, str):
-            value = unicode(value)
         if value is not None and prop == 'default':
             value = Binary.zpickle(value)
         values[amap.get(prop, prop)] = value
@@ -606,7 +589,7 @@
 def constraints2rql(cstrtypemap, constraints, rdefeid=None):
     for constraint in constraints:
         values = {'ct': cstrtypemap[constraint.type()],
-                  'value': text_type(constraint.serialize()),
+                  'value': constraint.serialize(),
                   'x': rdefeid} # when not specified, will have to be set by the caller
         yield 'INSERT CWConstraint X: X value %(value)s, X cstrtype CT, EDEF constrained_by X WHERE \
 CT eid %(ct)s, EDEF eid %(x)s', values
@@ -625,7 +608,7 @@
             # may occurs when modifying persistent schema
             continue
         for group_or_rqlexpr in grantedto:
-            if isinstance(group_or_rqlexpr, string_types):
+            if isinstance(group_or_rqlexpr, str):
                 # group
                 try:
                     yield ('SET X %s_permission Y WHERE Y eid %%(g)s, X eid %%(x)s' % action,
@@ -639,9 +622,9 @@
                 rqlexpr = group_or_rqlexpr
                 yield ('INSERT RQLExpression E: E expression %%(e)s, E exprtype %%(t)s, '
                        'E mainvars %%(v)s, X %s_permission E WHERE X eid %%(x)s' % action,
-                       {'e': text_type(rqlexpr.expression),
-                        'v': text_type(','.join(sorted(rqlexpr.mainvars))),
-                        't': text_type(rqlexpr.__class__.__name__)})
+                       {'e': rqlexpr.expression,
+                        'v': ','.join(sorted(rqlexpr.mainvars)),
+                        't': rqlexpr.__class__.__name__})
 
 # update functions
 
@@ -653,7 +636,7 @@
 def updaterschema2rql(rschema, eid):
     if rschema.rule:
         yield ('SET X rule %(r)s WHERE X eid %(x)s',
-               {'x': eid, 'r': text_type(rschema.rule)})
+               {'x': eid, 'r': rschema.rule})
     else:
         relations, values = rschema_relations_values(rschema)
         values['x'] = eid