From 032539868a1062e64a552c513352de539824c680 Mon Sep 17 00:00:00 2001
From: Yaroslav Halchenko <debian@onerussian.com>
Date: Thu, 17 Jan 2019 14:24:52 -0500
Subject: [PATCH 01/13] Dummy empty commit to facilitate long lived PR


From 2fe21983c39dcb0d6f6232ff4d2f33755ec47832 Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Wed, 20 Feb 2019 16:41:27 +0000
Subject: [PATCH 02/13] WIP: added venv to diff

---
 reproman/distributions/venv.py             |  1 +
 reproman/interface/diff.py                 | 14 +++++++---
 reproman/interface/tests/files/diff_1.yaml | 30 ++++++++++++++++++++++
 reproman/interface/tests/files/diff_2.yaml | 30 ++++++++++++++++++++++
 reproman/interface/tests/test_diff.py      | 12 +++++++++
 5 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/reproman/distributions/venv.py b/reproman/distributions/venv.py
index f66b65e54..cb7f8856a 100644
--- a/reproman/distributions/venv.py
+++ b/reproman/distributions/venv.py
@@ -47,6 +47,7 @@ class VenvEnvironment(SpecObject):
     path = attrib()
     python_version = attrib()
     packages = TypedList(VenvPackage)
+    _diff_cmp_fields = ('path', 'python_version')
 
 
 @attr.s
diff --git a/reproman/interface/diff.py b/reproman/interface/diff.py
index f77be7f62..56c04b66d 100644
--- a/reproman/interface/diff.py
+++ b/reproman/interface/diff.py
@@ -20,6 +20,7 @@
 from ..distributions.debian import DebianDistribution
 from ..distributions.conda import CondaDistribution
 from ..distributions.vcs import GitDistribution, SVNDistribution
+from ..distributions.venv import VenvDistribution, VenvEnvironment
 
 __docformat__ = 'restructuredtext'
 
@@ -88,7 +89,8 @@ def diff(env_1, env_2):
             DebianDistribution: 'Debian package', 
             CondaDistribution: 'Conda package', 
             GitDistribution: 'Git repository',
-            SVNDistribution: 'SVN repository'
+            SVNDistribution: 'SVN repository', 
+            VenvDistribution: 'Venv environment', 
         }
 
         env_1_dist_types = { d.__class__ for d in env_1.distributions }
@@ -103,12 +105,18 @@ def diff(env_1, env_2):
                         'pkg_diffs': []}
             dist_1 = env_1.get_distribution(dist_type)
             if dist_1:
-                pkgs_1 = {p._diff_cmp_id: p for p in dist_1.packages}
+                if dist_type == VenvDistribution:
+                    pkgs_1 = {p._diff_cmp_id: p for p in dist_1.environments}
+                else:
+                    pkgs_1 = {p._diff_cmp_id: p for p in dist_1.packages}
             else:
                 pkgs_1 = {}
             dist_2 = env_2.get_distribution(dist_type)
             if dist_2:
-                pkgs_2 = {p._diff_cmp_id: p for p in dist_2.packages}
+                if dist_type == VenvDistribution:
+                    pkgs_2 = {p._diff_cmp_id: p for p in dist_2.environments}
+                else:
+                    pkgs_2 = {p._diff_cmp_id: p for p in dist_2.packages}
             else:
                 pkgs_2 = {}
             dist_res['pkgs_1'] = pkgs_1
diff --git a/reproman/interface/tests/files/diff_1.yaml b/reproman/interface/tests/files/diff_1.yaml
index 08a098312..1873b86ca 100644
--- a/reproman/interface/tests/files/diff_1.yaml
+++ b/reproman/interface/tests/files/diff_1.yaml
@@ -58,4 +58,34 @@ distributions:
   - path: /path/1/to/different/svn/commit
     revision: 12
     uuid: 95e4b738-84c7-154c-f082-34d40e21fdd4
+- name: venv
+  path: /usr/bin/virtualenv
+  venv_version: 15.1.0
+  environments:
+  - path: /home/user/venvs/test/both
+    python_version: 2.7.15+
+    packages:
+    - name: six
+      version: 1.12.0
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
+      - lib/python2.7/site-packages/six.pyc
+      - lib/python2.7/site-packages/six.py
+  - path: /home/user/venvs/test/1_only
+    python_version: 2.7.15+
+    packages:
+    - name: funcsigs
+      version: 1.0.2
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/funcsigs-1.0.2.dist-info/METADATA
+    - name: rpaths
+      version: '0.13'
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/rpaths-0.13.dist-info/METADATA
 files: [/etc/a, /etc/b]
diff --git a/reproman/interface/tests/files/diff_2.yaml b/reproman/interface/tests/files/diff_2.yaml
index bed05c111..21eb718a7 100644
--- a/reproman/interface/tests/files/diff_2.yaml
+++ b/reproman/interface/tests/files/diff_2.yaml
@@ -58,4 +58,34 @@ distributions:
   - path: /path/2/to/different/svn/commit
     revision: 14
     uuid: 95e4b738-84c7-154c-f082-34d40e21fdd4
+- name: venv
+  path: /usr/bin/virtualenv
+  venv_version: 15.1.0
+  environments:
+  - path: /home/user/venvs/test/both
+    python_version: 2.7.15+
+    packages:
+    - name: six
+      version: 1.12.0
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
+      - lib/python2.7/site-packages/six.pyc
+      - lib/python2.7/site-packages/six.py
+  - path: /home/user/venvs/test/2_only
+    python_version: 2.7.15+
+    packages:
+    - name: funcsigs
+      version: 1.0.2
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/funcsigs-1.0.2.dist-info/METADATA
+    - name: rpaths
+      version: '0.13'
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/rpaths-0.13.dist-info/METADATA
 files: [/etc/c, /etc/b]
diff --git a/reproman/interface/tests/test_diff.py b/reproman/interface/tests/test_diff.py
index 77e0a0adb..0bc51b883 100644
--- a/reproman/interface/tests/test_diff.py
+++ b/reproman/interface/tests/test_diff.py
@@ -153,6 +153,18 @@ def test_diff_svn():
         assert_not_in('(/path/2/to/common/svn/repo)', outputs.out)
 
 
+def test_diff_venv():
+    with swallow_outputs() as outputs:
+        args = ['diff', diff_1_yaml, diff_2_yaml]
+        rv = main(args)
+        assert_equal(rv, 3)
+        assert_equal(outputs.err, '')
+        assert_in('Venv environments:', outputs.out)
+        assert_in('< /home/user/venvs/test/1_only 2.7.15+', outputs.out)
+        assert_in('> /home/user/venvs/test/2_only 2.7.15+', outputs.out)
+        assert_not_in('/home/user/venvs/test/both', outputs.out)
+
+
 def test_diff_satisfies_unsupported_distribution():
     # using subprocess.call() here because we're looking for a condition 
     # that raises an exception in main(), so it doesn't return and we 

From 66d8b673590f233eb239ebcf1f77784db97a964d Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Wed, 20 Mar 2019 21:02:22 +0000
Subject: [PATCH 03/13] replacing SpecObject._comparison_fields with
 _diff_cmp_fields + _diff_fields

---
 reproman/distributions/base.py   | 46 +++++++++++++++++++++-----------
 reproman/distributions/debian.py |  1 -
 reproman/distributions/redhat.py |  3 ++-
 3 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index 6f56083bb..ad6c11842 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -46,8 +46,6 @@ class SpecObject(object):
     _diff_cmp_fields = tuple()
     # Fields of the primary interest when showing diff
     _diff_fields = tuple()
-    # Fields used in determination of comparison (satisfied_by and identical_to)
-    _comparison_fields = tuple()
 
     @property
     def _diff_cmp_id(self):
@@ -60,12 +58,19 @@ def _diff_cmp_id(self):
 
     @property
     def _cmp_id(self):
-        if not self._comparison_fields:
+        if not self._diff_cmp_fields:
             # Might need to be gone or some custom exception
             raise RuntimeError(
-                "Cannot establish identity of %r since _comaprison_fields "
+                "Cannot establish identity of %r since _diff_cmp_fields "
                 "are not defined" % self)
-        return tuple(getattr(self, a) for a in self._comparison_fields)
+        if not self._diff_fields:
+            # Might need to be gone or some custom exception
+            raise RuntimeError(
+                "Cannot establish identity of %r since _diff_fields "
+                "are not defined" % self)
+        vals = [ getattr(self, a) for a in self._diff_cmp_fields ]
+        vals.extend([ getattr(self, a) for a in self._diff_fields ])
+        return tuple(vals)
 
     @property
     def _diff_vals(self):
@@ -94,8 +99,8 @@ def diff_subidentity_string(self):
 
     @property
     def identity_string(self):
-        """like diff_identity_string, but for _comparison_fields (used in 
-        satisfied_by comparisons)
+        """like diff_identity_string, but for both _diff_cmp_fields and 
+        _diff_fields (used in satisfied_by comparisons)
         """
         return " ".join(str(el) for el in self._cmp_id if el is not None)
 
@@ -137,15 +142,15 @@ def _satisfied_by(self, other):
         spec object.
 
         We require that the values of the attributes given by 
-        _comparison_fields are the same.  A specobject with a value of None 
-        for one of these attributes is less specific than one with 
-        a specific value; the former cannot satisfy the latter, 
-        but the latter can satisfy the former.
+        _diff_cmp_fields and _diff_fields are the same.  A specobject 
+        with a value of None for one of these attributes is less specific 
+        than one with a specific value; the former cannot satisfy the 
+        latter, but the latter can satisfy the former.
 
         TODO: Ensure we don't encounter the case where self is completely 
         unspecified (all values are None), in which case satisfied_by() 
         returns True by default.  Perhaps this is done by making 
-        sure that at least one of the _comparison_fields cannot be None.
+        sure that at least one of the _diff_cmp_fields cannot be None.
 
         TODO: derive _collection_type directly from _collection.  This isn't 
         possible at the moment because DebianDistribution.packages is 
@@ -162,7 +167,14 @@ def _satisfied_by(self, other):
             raise TypeError('don''t know how to determine if a %s is satisfied by a %s' % (self.__class__, other_collection_type))
         if not isinstance(other, self.__class__):
             raise TypeError('incompatible specobject types')
-        for attr_name in self._comparison_fields:
+        for attr_name in self._diff_cmp_fields:
+            self_value = getattr(self, attr_name)
+            other_value = getattr(other, attr_name)
+            if self_value is None:
+                continue
+            if self_value != other_value:
+                return False
+        for attr_name in self._diff_fields:
             self_value = getattr(self, attr_name)
             other_value = getattr(other, attr_name)
             if self_value is None:
@@ -176,11 +188,15 @@ def _identical_to(self, other):
         """Determine if the other object is identical to the spec object.
 
         We require that the objects are of the same type and that the 
-        values of the attributes given by _comparison_fields are the same.
+        values of the attributes given by _diff_cmp_fields and _diff_fields 
+        are the same.
         """
         if not isinstance(other, self.__class__):
             return False
-        for attr_name in self._comparison_fields:
+        for attr_name in self._diff_cmp_fields:
+            if getattr(self, attr_name) != getattr(other, attr_name):
+                return False
+        for attr_name in self._diff_fields:
             if getattr(self, attr_name) != getattr(other, attr_name):
                 return False
         return True
diff --git a/reproman/distributions/debian.py b/reproman/distributions/debian.py
index 8154953dc..db0a37e40 100644
--- a/reproman/distributions/debian.py
+++ b/reproman/distributions/debian.py
@@ -91,7 +91,6 @@ class DEBPackage(Package):
 
     _diff_cmp_fields = ('name', 'architecture')
     _diff_fields = ('version',)
-    _comparison_fields = ('name', 'architecture', 'version')
 
 _register_with_representer(DEBPackage)
 
diff --git a/reproman/distributions/redhat.py b/reproman/distributions/redhat.py
index 8f7baf0c4..87a48fefe 100644
--- a/reproman/distributions/redhat.py
+++ b/reproman/distributions/redhat.py
@@ -65,7 +65,8 @@ class RPMPackage(Package):
     vendor = attrib()
     url = attrib()
     files = attrib(default=attr.Factory(list), hash=False)
-    _comparison_fields = ('name', 'version', 'architecture')
+    _diff_cmp_fields = ('name', 'architecture')
+    _diff_fields = ('version',)
 
 
 _register_with_representer(RPMPackage)

From 3ab7a04e3c776245557771883b50f9556539ca0e Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Thu, 21 Mar 2019 13:44:23 +0000
Subject: [PATCH 04/13] refactored _satisfied_by() and _identical_to() in
 SpecObject

---
 reproman/distributions/base.py | 21 +++------------------
 1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index ad6c11842..57f7ff2a3 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -167,16 +167,7 @@ def _satisfied_by(self, other):
             raise TypeError('don''t know how to determine if a %s is satisfied by a %s' % (self.__class__, other_collection_type))
         if not isinstance(other, self.__class__):
             raise TypeError('incompatible specobject types')
-        for attr_name in self._diff_cmp_fields:
-            self_value = getattr(self, attr_name)
-            other_value = getattr(other, attr_name)
-            if self_value is None:
-                continue
-            if self_value != other_value:
-                return False
-        for attr_name in self._diff_fields:
-            self_value = getattr(self, attr_name)
-            other_value = getattr(other, attr_name)
+        for (self_value, other_value) in zip(self._cmp_id, other._cmp_id):
             if self_value is None:
                 continue
             if self_value != other_value:
@@ -189,17 +180,11 @@ def _identical_to(self, other):
 
         We require that the objects are of the same type and that the 
         values of the attributes given by _diff_cmp_fields and _diff_fields 
-        are the same.
+        (dereferenced in _cmp_id) are the same.
         """
         if not isinstance(other, self.__class__):
             return False
-        for attr_name in self._diff_cmp_fields:
-            if getattr(self, attr_name) != getattr(other, attr_name):
-                return False
-        for attr_name in self._diff_fields:
-            if getattr(self, attr_name) != getattr(other, attr_name):
-                return False
-        return True
+        return all(sv==ov for sv, ov in zip(self._cmp_id, other._cmp_id))
 
 
 def _register_with_representer(cls):

From 9599683742f99db8a0f6dbaadf510ecd2b4f63ec Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Thu, 21 Mar 2019 14:36:53 +0000
Subject: [PATCH 05/13] added class SpecDiff

---
 reproman/distributions/base.py | 57 ++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index 57f7ff2a3..64d537360 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -424,3 +424,60 @@ def _create_package(self, **package_fields):
         provided by _get_packagefields_for_files
         """
         return
+
+
+class SpecDiff:
+
+    """Difference object for SpecObjects.
+
+    Instantiate with SpecDiff(a, b).  a and b must be of the same type 
+    or TypeError is raised.  Either (but not both) may be None.
+
+    Attributes:
+
+        a, b: The two objects being compared.
+
+        If _diff_cmp_fields is defined for the SpecObjects:
+
+            diff_cmp_id: The _diff_cmp_id of the two objects.  If 
+                        _diff_cmp_id are different for the two objects, 
+                        they cannot be compared and ValueError is raised.
+
+            diff_vals_a, diff_vals_b: _diff_vals for a and b, respectively, 
+                                    or None if a or b is None.
+
+        For collection SpecObjects (e.g. DebianDistribution, containing 
+        DEBPackages; these have _collection_attribute defined), we also 
+        have:
+
+            collection: a list of SpecDiff objects for the contained 
+                        SpecObjects.
+    """
+
+    def __init__(self, a, b):
+        if not isinstance(a, (SpecObject, type(None))) \
+            or not isinstance(b, (SpecObject, type(None))):
+            raise TypeError('objects must be SpecObjects or None')
+        if not a and not b:
+            raise TypeError('objects cannot both be None')
+        if a and b and type(a) != type(b):
+            raise TypeError('objects must be of the same type')
+        self.cls = type(a) if a is not None else type(b)
+        self.a = a
+        self.b = b
+        if self.cls._diff_cmp_fields:
+            if a and b and a._diff_cmp_id != b._diff_cmp_id:
+                raise ValueError('objects\' _diff_cmp_id differ')
+            self.diff_vals_a = a._diff_vals if a else None
+            self.diff_vals_b = b._diff_vals if b else None
+            self.diff_cmp_id = a._diff_cmp_id if a else b._diff_cmp_id
+        if hasattr(a, '_collection_attribute'):
+            self.collection = []
+            a_collection = { c._diff_cmp_id: c for c in a.collection } if a else {}
+            b_collection = { c._diff_cmp_id: c for c in b.collection } if b else {}
+            all_cmp_ids = set(a_collection).union(b_collection)
+            for cmp_id in all_cmp_ids:
+                ac = a_collection[cmp_id] if cmp_id in a_collection else None
+                bc = b_collection[cmp_id] if cmp_id in b_collection else None
+                self.collection.append(SpecDiff(ac, bc))
+        return

From eaf140d356c323dc33715da293858646cd5f2de6 Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Tue, 2 Apr 2019 20:11:41 +0000
Subject: [PATCH 06/13] added _collection_attribute to CondaDistribution,
 GitDistribution, SVNDistribution, and VenvDistribution

---
 reproman/distributions/conda.py | 1 +
 reproman/distributions/vcs.py   | 4 ++++
 reproman/distributions/venv.py  | 1 +
 3 files changed, 6 insertions(+)

diff --git a/reproman/distributions/conda.py b/reproman/distributions/conda.py
index 462d7dcf7..7c529e863 100644
--- a/reproman/distributions/conda.py
+++ b/reproman/distributions/conda.py
@@ -136,6 +136,7 @@ class CondaDistribution(Distribution):
     environments = TypedList(CondaEnvironment)
 
     _cmp_field = ('path',)
+    _collection_attribute = 'packages'
 
     def initiate(self, environment):
         """
diff --git a/reproman/distributions/vcs.py b/reproman/distributions/vcs.py
index b118fd48c..200f8845e 100644
--- a/reproman/distributions/vcs.py
+++ b/reproman/distributions/vcs.py
@@ -125,6 +125,8 @@ class GitDistribution(VCSDistribution):
     _cmd = "git"
     packages = TypedList(GitRepo)
 
+    _collection_attribute = 'packages'
+
     def initiate(self, session=None):
         pass
 
@@ -296,6 +298,8 @@ class SVNDistribution(VCSDistribution):
     _cmd = "svn"
     packages = TypedList(SVNRepo)
 
+    _collection_attribute = 'packages'
+
     def install_packages(self, session, use_version=True):
         raise NotImplementedError
 SVNRepo._distribution = SVNDistribution
diff --git a/reproman/distributions/venv.py b/reproman/distributions/venv.py
index 0efff7ec9..92a6c41dd 100644
--- a/reproman/distributions/venv.py
+++ b/reproman/distributions/venv.py
@@ -55,6 +55,7 @@ class VenvDistribution(Distribution):
     path = attrib()
     venv_version = attrib()
     environments = TypedList(VenvEnvironment)
+    _collection_attribute = 'environments'
 
     def initiate(self, _):
         return

From 029dd3d5a38dc27cf0b96a411d7702a5749dad5d Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Tue, 2 Apr 2019 20:24:53 +0000
Subject: [PATCH 07/13] using SpecDiff for diff interface

---
 reproman/interface/diff.py | 88 +++++++++++++++++---------------------
 1 file changed, 39 insertions(+), 49 deletions(-)

diff --git a/reproman/interface/diff.py b/reproman/interface/diff.py
index 429f793e6..2aa40402b 100644
--- a/reproman/interface/diff.py
+++ b/reproman/interface/diff.py
@@ -21,6 +21,7 @@
 from ..distributions.conda import CondaDistribution
 from ..distributions.vcs import GitDistribution, SVNDistribution
 from ..distributions.venv import VenvDistribution, VenvEnvironment
+from ..distributions.base import SpecDiff
 
 __docformat__ = 'restructuredtext'
 
@@ -82,8 +83,6 @@ def __call__(prov1, prov2, satisfies):
     @staticmethod
     def diff(env_1, env_2):
 
-        result = {'method': 'diff', 'distributions': []}
-
         # distribution type -> package type string
         supported_distributions = {
             DebianDistribution: 'Debian package', 
@@ -97,47 +96,24 @@ def diff(env_1, env_2):
         env_2_dist_types = { d.__class__ for d in env_2.distributions }
         all_dist_types = env_1_dist_types.union(env_2_dist_types)
 
+        diffs = []
+
         for dist_type in all_dist_types:
             if dist_type not in supported_distributions:
                 msg = 'diff doesn\'t know how to handle %s' % str(dist_type)
                 raise ValueError(msg)
-            dist_res = {'pkg_type': supported_distributions[dist_type], 
-                        'pkg_diffs': []}
             dist_1 = env_1.get_distribution(dist_type)
-            if dist_1:
-                if dist_type == VenvDistribution:
-                    pkgs_1 = {p._diff_cmp_id: p for p in dist_1.environments}
-                else:
-                    pkgs_1 = {p._diff_cmp_id: p for p in dist_1.packages}
-            else:
-                pkgs_1 = {}
             dist_2 = env_2.get_distribution(dist_type)
-            if dist_2:
-                if dist_type == VenvDistribution:
-                    pkgs_2 = {p._diff_cmp_id: p for p in dist_2.environments}
-                else:
-                    pkgs_2 = {p._diff_cmp_id: p for p in dist_2.packages}
-            else:
-                pkgs_2 = {}
-            dist_res['pkgs_1'] = pkgs_1
-            dist_res['pkgs_2'] = pkgs_2
-            pkgs_1_s = set(pkgs_1)
-            pkgs_2_s = set(pkgs_2)
-            dist_res['pkgs_only_1'] = pkgs_1_s - pkgs_2_s
-            dist_res['pkgs_only_2'] = pkgs_2_s - pkgs_1_s
-            for cmp_key in pkgs_1_s.intersection(pkgs_2_s):
-                package_1 = pkgs_1[cmp_key]
-                package_2 = pkgs_2[cmp_key]
-                if package_1._diff_vals != package_2._diff_vals:
-                    dist_res['pkg_diffs'].append((package_1, package_2))
-            result['distributions'].append(dist_res)
+            diffs.append({'diff': SpecDiff(dist_1, dist_2), 
+                          'pkg_type': supported_distributions[dist_type]})
 
         files1 = set(env_1.files)
         files2 = set(env_2.files)
-        result['files_1_only'] = files1 - files2
-        result['files_2_only'] = files2 - files1
 
-        return result
+        return {'method': 'diff', 
+                'diffs': diffs, 
+                'files_1_only': files1 - files2, 
+                'files_2_only': files2 - files1}
 
     @staticmethod
     def satisfies(env_1, env_2):
@@ -188,30 +164,44 @@ def render_cmdline_diff(result):
 
         status = 0
 
-        for dist_res in result['distributions']:
+        for diff_d in result['diffs']:
 
-            if dist_res['pkgs_only_1'] or dist_res['pkgs_only_2']:
-                print(_make_plural(dist_res['pkg_type']) + ':')
+            diff = diff_d['diff']
+            pkg_type = diff_d['pkg_type']
 
-            if dist_res['pkgs_only_1']:
-                for cmp_key in sorted(dist_res['pkgs_only_1']):
-                    package = dist_res['pkgs_1'][cmp_key]
+            pkgs_only_1 = {}
+            pkgs_only_2 = {}
+            pkg_diffs = []
+
+            for pkg_diff in diff.collection:
+                if pkg_diff.a is None:
+                    pkgs_only_2[pkg_diff.b._diff_cmp_id] = pkg_diff.b
+                elif pkg_diff.b is None:
+                    pkgs_only_1[pkg_diff.a._diff_cmp_id] = pkg_diff.a
+                elif pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
+                    pkg_diffs.append(pkg_diff)
+            if pkgs_only_1 or pkgs_only_2:
+                print(_make_plural(pkg_type) + ':')
+
+            if pkgs_only_1:
+                for cmp_key in sorted(pkgs_only_1):
+                    package = pkgs_only_1[cmp_key]
                     print('< %s' % package.diff_identity_string)
                 status = 3
-            if dist_res['pkgs_only_1'] and dist_res['pkgs_only_2']:
+            if pkgs_only_1 and pkgs_only_2:
                 print('---')
-            if dist_res['pkgs_only_2']:
-                for cmp_key in sorted(dist_res['pkgs_only_2']):
-                    package = dist_res['pkgs_2'][cmp_key]
+            if pkgs_only_2:
+                for cmp_key in sorted(pkgs_only_2):
+                    package = pkgs_only_2[cmp_key]
                     print('> %s' % package.diff_identity_string)
                 status = 3
 
-            for (package_1, package_2) in dist_res['pkg_diffs']:
-                print('%s %s:' % (dist_res['pkg_type'], 
-                                  " ".join(package_1._diff_cmp_id)))
-                print('< %s' % package_1.diff_subidentity_string)
-                print('---')
-                print('> %s' % package_2.diff_subidentity_string)
+            if pkg_diffs:
+                for pkg_diff in pkg_diffs:
+                    print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
+                    print('< %s' % pkg_diff.a.diff_subidentity_string)
+                    print('---')
+                    print('> %s' % pkg_diff.b.diff_subidentity_string)
                 status = 3
 
         if result['files_1_only'] or result['files_2_only']:

From 17525c752a34e7e6a338fb5d1b72ffed0dbfbadd Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Tue, 16 Apr 2019 17:16:40 +0000
Subject: [PATCH 08/13] supporting files lists in SpecDiff

---
 reproman/distributions/base.py | 49 +++++++++++++++++++++++-----------
 reproman/interface/diff.py     | 17 +++++++++---
 2 files changed, 46 insertions(+), 20 deletions(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index 64d537360..e5b15aba9 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -452,11 +452,15 @@ class SpecDiff:
 
             collection: a list of SpecDiff objects for the contained 
                         SpecObjects.
+
+    If a and b are lists, they are treated as files specifications, and 
+    self.collection is a list of (fname_a, fname_b) tuples.
+    TODO: give files and file collections their own specobjects
     """
 
     def __init__(self, a, b):
-        if not isinstance(a, (SpecObject, type(None))) \
-            or not isinstance(b, (SpecObject, type(None))):
+        if not isinstance(a, (SpecObject, list, type(None))) \
+            or not isinstance(b, (SpecObject, list, type(None))):
             raise TypeError('objects must be SpecObjects or None')
         if not a and not b:
             raise TypeError('objects cannot both be None')
@@ -465,19 +469,32 @@ def __init__(self, a, b):
         self.cls = type(a) if a is not None else type(b)
         self.a = a
         self.b = b
-        if self.cls._diff_cmp_fields:
-            if a and b and a._diff_cmp_id != b._diff_cmp_id:
-                raise ValueError('objects\' _diff_cmp_id differ')
-            self.diff_vals_a = a._diff_vals if a else None
-            self.diff_vals_b = b._diff_vals if b else None
-            self.diff_cmp_id = a._diff_cmp_id if a else b._diff_cmp_id
-        if hasattr(a, '_collection_attribute'):
+        if self.cls == list:
+            a_collection = set(a)
+            b_collection = set(b)
             self.collection = []
-            a_collection = { c._diff_cmp_id: c for c in a.collection } if a else {}
-            b_collection = { c._diff_cmp_id: c for c in b.collection } if b else {}
-            all_cmp_ids = set(a_collection).union(b_collection)
-            for cmp_id in all_cmp_ids:
-                ac = a_collection[cmp_id] if cmp_id in a_collection else None
-                bc = b_collection[cmp_id] if cmp_id in b_collection else None
-                self.collection.append(SpecDiff(ac, bc))
+            for fname in set(a_collection).union(b_collection):
+                if fname not in a_collection:
+                    self.collection.append((None, fname))
+                elif fname not in b_collection:
+                    self.collection.append((fname, None))
+                else:
+                    self.collection.append((fname, fname))
+            pass
+        else:
+            if self.cls._diff_cmp_fields:
+                if a and b and a._diff_cmp_id != b._diff_cmp_id:
+                    raise ValueError('objects\' _diff_cmp_id differ')
+                self.diff_vals_a = a._diff_vals if a else None
+                self.diff_vals_b = b._diff_vals if b else None
+                self.diff_cmp_id = a._diff_cmp_id if a else b._diff_cmp_id
+            if hasattr(a, '_collection_attribute'):
+                self.collection = []
+                a_collection = { c._diff_cmp_id: c for c in a.collection } if a else {}
+                b_collection = { c._diff_cmp_id: c for c in b.collection } if b else {}
+                all_cmp_ids = set(a_collection).union(b_collection)
+                for cmp_id in all_cmp_ids:
+                    ac = a_collection[cmp_id] if cmp_id in a_collection else None
+                    bc = b_collection[cmp_id] if cmp_id in b_collection else None
+                    self.collection.append(SpecDiff(ac, bc))
         return
diff --git a/reproman/interface/diff.py b/reproman/interface/diff.py
index 2aa40402b..1a6a76d34 100644
--- a/reproman/interface/diff.py
+++ b/reproman/interface/diff.py
@@ -107,6 +107,9 @@ def diff(env_1, env_2):
             diffs.append({'diff': SpecDiff(dist_1, dist_2), 
                           'pkg_type': supported_distributions[dist_type]})
 
+        diffs.append({'diff': SpecDiff(env_1.files, env_2.files), 
+                      'pkg_type': 'files'})
+
         files1 = set(env_1.files)
         files2 = set(env_2.files)
 
@@ -169,6 +172,10 @@ def render_cmdline_diff(result):
             diff = diff_d['diff']
             pkg_type = diff_d['pkg_type']
 
+            if pkg_type == 'files':
+                files_diff = diff_d['diff']
+                continue
+
             pkgs_only_1 = {}
             pkgs_only_2 = {}
             pkg_diffs = []
@@ -204,13 +211,15 @@ def render_cmdline_diff(result):
                     print('> %s' % pkg_diff.b.diff_subidentity_string)
                 status = 3
 
-        if result['files_1_only'] or result['files_2_only']:
+        files_1_only = [ t[0] for t in files_diff.collection if t[1] is None ]
+        files_2_only = [ t[1] for t in files_diff.collection if t[0] is None ]
+        if files_1_only or files_2_only:
             print('Files:')
-            for fname in result['files_1_only']:
+            for fname in files_1_only:
                 print('< %s' % fname)
-            if result['files_1_only'] and result['files_2_only']:
+            if files_1_only and files_2_only:
                 print('---')
-            for fname in result['files_2_only']:
+            for fname in files_2_only:
                 print('> %s' % fname)
             status = 3
 

From 138c2a6eef79fdc7686a8f5ba96e46c9b472c82b Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Tue, 16 Apr 2019 17:52:53 +0000
Subject: [PATCH 09/13] BF: in SpecDiff, checking for collection attribute in
 specobject class, not instance (which may be None)

---
 reproman/distributions/base.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index e5b15aba9..2cfbe2176 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -488,7 +488,7 @@ def __init__(self, a, b):
                 self.diff_vals_a = a._diff_vals if a else None
                 self.diff_vals_b = b._diff_vals if b else None
                 self.diff_cmp_id = a._diff_cmp_id if a else b._diff_cmp_id
-            if hasattr(a, '_collection_attribute'):
+            if hasattr(self.cls, '_collection_attribute'):
                 self.collection = []
                 a_collection = { c._diff_cmp_id: c for c in a.collection } if a else {}
                 b_collection = { c._diff_cmp_id: c for c in b.collection } if b else {}

From 39f5f4e3ea881de587672d918e5686e6bf707870 Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Tue, 16 Apr 2019 20:57:25 +0000
Subject: [PATCH 10/13] added SpecDiff attributes a_only, b_only, and diffs

---
 reproman/distributions/base.py | 26 +++++++++++++++++++++-
 reproman/interface/diff.py     | 40 ++++++++++------------------------
 2 files changed, 36 insertions(+), 30 deletions(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index 2cfbe2176..6b43b660d 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -453,6 +453,15 @@ class SpecDiff:
             collection: a list of SpecDiff objects for the contained 
                         SpecObjects.
 
+            a_only: SpecObjects from collection that only appear in the first 
+                    passed SpecObject
+
+            b_only: SpecObjects from collection that only appear in the second 
+                    passed SpecObject
+
+            diffs: SpecDiff objects in collection that appear in both 
+                    passed SpecObject
+
     If a and b are lists, they are treated as files specifications, and 
     self.collection is a list of (fname_a, fname_b) tuples.
     TODO: give files and file collections their own specobjects
@@ -480,7 +489,6 @@ def __init__(self, a, b):
                     self.collection.append((fname, None))
                 else:
                     self.collection.append((fname, fname))
-            pass
         else:
             if self.cls._diff_cmp_fields:
                 if a and b and a._diff_cmp_id != b._diff_cmp_id:
@@ -497,4 +505,20 @@ def __init__(self, a, b):
                     ac = a_collection[cmp_id] if cmp_id in a_collection else None
                     bc = b_collection[cmp_id] if cmp_id in b_collection else None
                     self.collection.append(SpecDiff(ac, bc))
+        if hasattr(self, 'collection'):
+            self.a_only = []
+            self.b_only = []
+            self.diffs = []
+            for pkg_diff in self.collection:
+                if isinstance(pkg_diff, tuple):
+                    (a, b) = pkg_diff
+                else:
+                    a = pkg_diff.a
+                    b = pkg_diff.b
+                if not a:
+                    self.b_only.append(b)
+                elif not b:
+                    self.a_only.append(a)
+                elif not isinstance(pkg_diff, tuple) and pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
+                    self.diffs.append(pkg_diff)
         return
diff --git a/reproman/interface/diff.py b/reproman/interface/diff.py
index 1a6a76d34..22e857fd7 100644
--- a/reproman/interface/diff.py
+++ b/reproman/interface/diff.py
@@ -176,39 +176,21 @@ def render_cmdline_diff(result):
                 files_diff = diff_d['diff']
                 continue
 
-            pkgs_only_1 = {}
-            pkgs_only_2 = {}
-            pkg_diffs = []
-
-            for pkg_diff in diff.collection:
-                if pkg_diff.a is None:
-                    pkgs_only_2[pkg_diff.b._diff_cmp_id] = pkg_diff.b
-                elif pkg_diff.b is None:
-                    pkgs_only_1[pkg_diff.a._diff_cmp_id] = pkg_diff.a
-                elif pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
-                    pkg_diffs.append(pkg_diff)
-            if pkgs_only_1 or pkgs_only_2:
+            if diff.a_only or diff.b_only:
                 print(_make_plural(pkg_type) + ':')
-
-            if pkgs_only_1:
-                for cmp_key in sorted(pkgs_only_1):
-                    package = pkgs_only_1[cmp_key]
-                    print('< %s' % package.diff_identity_string)
                 status = 3
-            if pkgs_only_1 and pkgs_only_2:
+            for package in diff.a_only:
+                print('< %s' % package.diff_identity_string)
+            if diff.a_only and diff.b_only:
                 print('---')
-            if pkgs_only_2:
-                for cmp_key in sorted(pkgs_only_2):
-                    package = pkgs_only_2[cmp_key]
-                    print('> %s' % package.diff_identity_string)
-                status = 3
+            for package in diff.b_only:
+                print('> %s' % package.diff_identity_string)
 
-            if pkg_diffs:
-                for pkg_diff in pkg_diffs:
-                    print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
-                    print('< %s' % pkg_diff.a.diff_subidentity_string)
-                    print('---')
-                    print('> %s' % pkg_diff.b.diff_subidentity_string)
+            for pkg_diff in diff.diffs:
+                print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
+                print('< %s' % pkg_diff.a.diff_subidentity_string)
+                print('---')
+                print('> %s' % pkg_diff.b.diff_subidentity_string)
                 status = 3
 
         files_1_only = [ t[0] for t in files_diff.collection if t[1] is None ]

From cf5db619c2176029aefc2980ec90c0735cf929fc Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Wed, 17 Apr 2019 15:53:04 +0000
Subject: [PATCH 11/13] in SpecDiff:     changed diff to a_and_b     collecting
 diff objects in a_only and b_only

---
 reproman/distributions/base.py | 22 +++++++++++-----------
 reproman/interface/diff.py     | 23 ++++++++++++-----------
 2 files changed, 23 insertions(+), 22 deletions(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index 6b43b660d..2ac66a9c9 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -453,14 +453,14 @@ class SpecDiff:
             collection: a list of SpecDiff objects for the contained 
                         SpecObjects.
 
-            a_only: SpecObjects from collection that only appear in the first 
-                    passed SpecObject
+            a_only: SpecDiff objects from collection that only appear in the 
+                    first passed SpecObject
 
-            b_only: SpecObjects from collection that only appear in the second 
-                    passed SpecObject
+            b_only: SpecDiff objects from collection that only appear in the 
+                    second passed SpecObject
 
-            diffs: SpecDiff objects in collection that appear in both 
-                    passed SpecObject
+            a_and_b: SpecDiff objects in collection that appear in both 
+                     passed SpecObjects
 
     If a and b are lists, they are treated as files specifications, and 
     self.collection is a list of (fname_a, fname_b) tuples.
@@ -508,7 +508,7 @@ def __init__(self, a, b):
         if hasattr(self, 'collection'):
             self.a_only = []
             self.b_only = []
-            self.diffs = []
+            self.a_and_b = []
             for pkg_diff in self.collection:
                 if isinstance(pkg_diff, tuple):
                     (a, b) = pkg_diff
@@ -516,9 +516,9 @@ def __init__(self, a, b):
                     a = pkg_diff.a
                     b = pkg_diff.b
                 if not a:
-                    self.b_only.append(b)
+                    self.b_only.append(pkg_diff)
                 elif not b:
-                    self.a_only.append(a)
-                elif not isinstance(pkg_diff, tuple) and pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
-                    self.diffs.append(pkg_diff)
+                    self.a_only.append(pkg_diff)
+                else:
+                    self.a_and_b.append(pkg_diff)
         return
diff --git a/reproman/interface/diff.py b/reproman/interface/diff.py
index 22e857fd7..06be43f04 100644
--- a/reproman/interface/diff.py
+++ b/reproman/interface/diff.py
@@ -179,19 +179,20 @@ def render_cmdline_diff(result):
             if diff.a_only or diff.b_only:
                 print(_make_plural(pkg_type) + ':')
                 status = 3
-            for package in diff.a_only:
-                print('< %s' % package.diff_identity_string)
+            for pkg_diff in diff.a_only:
+                print('< %s' % pkg_diff.a.diff_identity_string)
             if diff.a_only and diff.b_only:
                 print('---')
-            for package in diff.b_only:
-                print('> %s' % package.diff_identity_string)
-
-            for pkg_diff in diff.diffs:
-                print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
-                print('< %s' % pkg_diff.a.diff_subidentity_string)
-                print('---')
-                print('> %s' % pkg_diff.b.diff_subidentity_string)
-                status = 3
+            for pkg_diff in diff.b_only:
+                print('> %s' % pkg_diff.b.diff_identity_string)
+
+            for pkg_diff in diff.a_and_b:
+                if pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
+                    print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
+                    print('< %s' % pkg_diff.a.diff_subidentity_string)
+                    print('---')
+                    print('> %s' % pkg_diff.b.diff_subidentity_string)
+                    status = 3
 
         files_1_only = [ t[0] for t in files_diff.collection if t[1] is None ]
         files_2_only = [ t[1] for t in files_diff.collection if t[0] is None ]

From df6d69df1e3a4ab64a661525c1eb5461e0a8b9a6 Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Wed, 17 Apr 2019 16:00:06 +0000
Subject: [PATCH 12/13] added venv hierarchy to diff

---
 reproman/distributions/venv.py             |  3 +++
 reproman/interface/diff.py                 | 30 +++++++++++++++++-----
 reproman/interface/tests/files/diff_1.yaml | 19 ++++++++++++++
 reproman/interface/tests/files/diff_2.yaml | 19 ++++++++++++++
 4 files changed, 65 insertions(+), 6 deletions(-)

diff --git a/reproman/distributions/venv.py b/reproman/distributions/venv.py
index 92a6c41dd..e017bdfcd 100644
--- a/reproman/distributions/venv.py
+++ b/reproman/distributions/venv.py
@@ -38,6 +38,8 @@ class VenvPackage(Package):
     location = attrib()
     editable = attrib(default=False)
     files = attrib(default=attr.Factory(list))
+    _diff_cmp_fields = ('name', )
+    _diff_fields = ('version', )
 
 
 @attr.s
@@ -46,6 +48,7 @@ class VenvEnvironment(SpecObject):
     python_version = attrib()
     packages = TypedList(VenvPackage)
     _diff_cmp_fields = ('path', 'python_version')
+    _collection_attribute = 'packages'
 
 
 @attr.s
diff --git a/reproman/interface/diff.py b/reproman/interface/diff.py
index 06be43f04..57a493cdd 100644
--- a/reproman/interface/diff.py
+++ b/reproman/interface/diff.py
@@ -187,12 +187,30 @@ def render_cmdline_diff(result):
                 print('> %s' % pkg_diff.b.diff_identity_string)
 
             for pkg_diff in diff.a_and_b:
-                if pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
-                    print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
-                    print('< %s' % pkg_diff.a.diff_subidentity_string)
-                    print('---')
-                    print('> %s' % pkg_diff.b.diff_subidentity_string)
-                    status = 3
+                if not hasattr(pkg_diff, 'collection'):
+                    if pkg_diff.diff_vals_a != pkg_diff.diff_vals_b:
+                        print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
+                        print('< %s' % pkg_diff.a.diff_subidentity_string)
+                        print('---')
+                        print('> %s' % pkg_diff.b.diff_subidentity_string)
+                        status = 3
+                else:
+                    a_only = [ pd.a for pd in pkg_diff.a_only ]
+                    b_only = [ pd.b for pd in pkg_diff.b_only ]
+                    ab = [ pd for pd in pkg_diff.a_and_b 
+                            if pd.diff_vals_a != pd.diff_vals_b ]
+                    if a_only or b_only or ab:
+                        print('%s %s:' % (pkg_type, ' '.join(pkg_diff.diff_cmp_id)))
+                        for pkg in a_only:
+                            print('< %s' % pkg.diff_identity_string)
+                        for pd in ab:
+                            print('< %s %s' % (pd.a.diff_identity_string, pd.a.diff_subidentity_string))
+                        if (a_only and b_only) or ab:
+                            print('---')
+                        for pkg in b_only:
+                            print('> %s' % pkg.diff_identity_string)
+                        for pd in ab:
+                            print('> %s %s' % (pd.b.diff_identity_string, pd.b.diff_subidentity_string))
 
         files_1_only = [ t[0] for t in files_diff.collection if t[1] is None ]
         files_2_only = [ t[1] for t in files_diff.collection if t[0] is None ]
diff --git a/reproman/interface/tests/files/diff_1.yaml b/reproman/interface/tests/files/diff_1.yaml
index 1873b86ca..40c498f02 100644
--- a/reproman/interface/tests/files/diff_1.yaml
+++ b/reproman/interface/tests/files/diff_1.yaml
@@ -73,6 +73,25 @@ distributions:
       - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
       - lib/python2.7/site-packages/six.pyc
       - lib/python2.7/site-packages/six.py
+  - path: /home/user/venvs/test/bth_2
+    python_version: 2.7.15+
+    packages:
+    - name: one_only
+      version: 1.12.0
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
+      - lib/python2.7/site-packages/six.pyc
+      - lib/python2.7/site-packages/six.py
+    - name: version_mismatch
+      version: 1.1.0
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
+      - lib/python2.7/site-packages/six.pyc
+      - lib/python2.7/site-packages/six.py
   - path: /home/user/venvs/test/1_only
     python_version: 2.7.15+
     packages:
diff --git a/reproman/interface/tests/files/diff_2.yaml b/reproman/interface/tests/files/diff_2.yaml
index 21eb718a7..ff9939fc3 100644
--- a/reproman/interface/tests/files/diff_2.yaml
+++ b/reproman/interface/tests/files/diff_2.yaml
@@ -73,6 +73,25 @@ distributions:
       - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
       - lib/python2.7/site-packages/six.pyc
       - lib/python2.7/site-packages/six.py
+  - path: /home/user/venvs/test/bth_2
+    python_version: 2.7.15+
+    packages:
+    - name: two_only
+      version: 1.12.0
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
+      - lib/python2.7/site-packages/six.pyc
+      - lib/python2.7/site-packages/six.py
+    - name: version_mismatch
+      version: 1.2.0
+      local: true
+      location: /home/user/venvs/test/lib/python2.7/site-packages
+      files:
+      - lib/python2.7/site-packages/six-1.12.0.dist-info/METADATA
+      - lib/python2.7/site-packages/six.pyc
+      - lib/python2.7/site-packages/six.py
   - path: /home/user/venvs/test/2_only
     python_version: 2.7.15+
     packages:

From fc4a84822f66dc0022493e7dfaaa25758612c87c Mon Sep 17 00:00:00 2001
From: Christian Haselgrove <christian.haselgrove@umassmed.edu>
Date: Thu, 16 May 2019 18:55:37 +0000
Subject: [PATCH 13/13] allowing two empty lists to be given to SpecDiff

---
 reproman/distributions/base.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/reproman/distributions/base.py b/reproman/distributions/base.py
index 2ac66a9c9..c4bfa6577 100644
--- a/reproman/distributions/base.py
+++ b/reproman/distributions/base.py
@@ -471,7 +471,7 @@ def __init__(self, a, b):
         if not isinstance(a, (SpecObject, list, type(None))) \
             or not isinstance(b, (SpecObject, list, type(None))):
             raise TypeError('objects must be SpecObjects or None')
-        if not a and not b:
+        if a is None and b is None:
             raise TypeError('objects cannot both be None')
         if a and b and type(a) != type(b):
             raise TypeError('objects must be of the same type')