Use InstallRequirement.extras for the diff in the Resolver.

The extras are combined in the InstallRequirement.extras, not in the
Requirement.extras. Comparing the Requirement.extras could cause flakyness in
the Resolver stabilisation, as the list of extras would vary based on the
iteration order on the set of InstallRequirement.

CHANGELOG.md

@@ -12,6 +12,7 @@ when `--allow-unsafe` was not set. ([#517](https://github.com/jazzband/pip-tools
 (thus losing their VCS directory) and `python setup.py egg_info` fails. ([#385](https://github.com/jazzband/pip-tools/pull/385#) and [#538](https://github.com/jazzband/pip-tools/pull/538)). Thanks @blueyed and @dfee
 - Fixed bug where some primary dependencies were annotated with "via" info comments. ([#542](https://github.com/jazzband/pip-tools/pull/542)). Thanks @quantus
 - Fixed bug where pkg-resources would be removed by pip-sync in Ubuntu. ([#555](https://github.com/jazzband/pip-tools/pull/555)). Thanks @cemsbr
+- Fixed bug where the resolver would sometime not stabilize on requirements specifying extras. ([#566](https://github.com/jazzband/pip-tools/pull/566)). Thanks @vphilippon
 
 # 1.9.0 (2017-04-12)
 

piptools/resolver.py

@@ -32,11 +32,11 @@ class RequirementSummary(object):
     """
     Summary of a requirement's properties for comparison purposes.
     """
-    def __init__(self, req):
-        self.req = req
-        self.key = key_from_req(req)
-        self.extras = str(sorted(req.extras))
-        self.specifier = str(req.specifier)
+    def __init__(self, ireq):
+        self.req = ireq.req
+        self.key = key_from_req(ireq.req)
+        self.extras = str(sorted(ireq.extras))
+        self.specifier = str(ireq.specifier)
 
     def __eq__(self, other):
         return str(self) == str(other)
@@ -210,11 +210,11 @@ def _resolve_one_round(self):
 
         # NOTE: We need to compare RequirementSummary objects, since
         # InstallRequirement does not define equality
-        diff = {RequirementSummary(t.req) for t in theirs} - {RequirementSummary(t.req) for t in self.their_constraints}
-        removed = ({RequirementSummary(t.req) for t in self.their_constraints} -
-                   {RequirementSummary(t.req) for t in theirs})
-        unsafe = ({RequirementSummary(t.req) for t in unsafe_constraints} -
-                  {RequirementSummary(t.req) for t in self.unsafe_constraints})
+        diff = {RequirementSummary(t) for t in theirs} - {RequirementSummary(t) for t in self.their_constraints}
+        removed = ({RequirementSummary(t) for t in self.their_constraints} -
+                   {RequirementSummary(t) for t in theirs})
+        unsafe = ({RequirementSummary(t) for t in unsafe_constraints} -
+                  {RequirementSummary(t) for t in self.unsafe_constraints})
 
         has_changed = len(diff) > 0 or len(removed) > 0 or len(unsafe) > 0
         if has_changed: