Merge pull request #282 from buildout/reinout-constraint-logging

Nicer version constraint logging + better requirement conflict info logging

.travis.yml

@@ -2,9 +2,9 @@ language: python
 env:
     - PYTHON_VER=2.6
     - PYTHON_VER=2.7
-    - PYTHON_VER=3.2
     - PYTHON_VER=3.3
     - PYTHON_VER=3.4
+    - PYTHON_VER=3.5
 
 sudo: false
 cache:

CHANGES.rst

@@ -4,7 +4,17 @@ Change History
 2.4.8 (unreleased)
 ==================
 
-- Nothing changed yet.
+- Added more elaborate version and requirement information when there's a
+  version conflict. Previously, you could get a report of a version conflict
+  without information about which dependency requested the conflicing
+  requirement.
+
+  Now all this information is logged and displayed in case of an error.
+  [reinout]
+
+- Dropped 3.2 support (at least in the automatic tests) as setuptools will
+  soon stop supporting it. Added python 3.5 to the automatic tests.
+  [reinout]
 
 
 2.4.7 (2015-10-29)

Makefile

@@ -19,6 +19,10 @@ ifeq ($(PYTHON_VER),3.4)
 	PYTHON_MINOR ?= 3.4.2
 	PYTHON_CONFIGURE_ARGS ?= --without-ensurepip
 endif
+ifeq ($(PYTHON_VER),3.5)
+	PYTHON_MINOR ?= 3.5.0
+	PYTHON_CONFIGURE_ARGS ?= --without-ensurepip
+endif
 
 ifndef PYTHON_MINOR
     $(error Please specify desired PYTHON_MINOR for Python $(PYTHON_VER))

setup.py

@@ -102,9 +102,9 @@ setup(
        'Programming Language :: Python :: 2.6',
        'Programming Language :: Python :: 2.7',
        'Programming Language :: Python :: 3',
-       'Programming Language :: Python :: 3.2',
        'Programming Language :: Python :: 3.3',
        'Programming Language :: Python :: 3.4',
+       'Programming Language :: Python :: 3.5',
        'Topic :: Software Development :: Build Tools',
        'Topic :: Software Development :: Libraries :: Python Modules',
        ],

src/zc/buildout/easy_install.py

@@ -222,10 +222,28 @@ class Installer:
         self._newest = newest
         self._env = pkg_resources.Environment(path)
         self._index = _get_index(index, links, self._allow_hosts)
+        self._requirements_and_constraints = []
 
         if versions is not None:
             self._versions = normalize_versions(versions)
 
+    def _version_conflict_information(self, name):
+        """Return textual requirements/constraint information for debug purposes
+
+        We do a very simple textual search, as that filters out most
+        extraneous information witout missing anything.
+
+        """
+        output = [
+            "Version and requirements information containing %s:" % name]
+        version_constraint = self._versions.get(name)
+        if version_constraint:
+            output.append(
+                "[versions] constraint on %s: %s" % (name, version_constraint))
+        output += [line for line in self._requirements_and_constraints
+                   if name.lower() in line.lower()]
+        return '\n  '.join(output)
+
     def _satisfied(self, req, source=None):
         dists = [dist for dist in self._env[req.project_name] if dist in req]
         if not dists:
@@ -608,14 +626,24 @@ class Installer:
 
 
     def _constrain(self, requirement):
+        """Return requirement with optional [versions] constraint added."""
         constraint = self._versions.get(requirement.project_name.lower())
         if constraint:
-            requirement = _constrained_requirement(constraint, requirement)
+            try:
+                requirement = _constrained_requirement(constraint,
+                                                       requirement)
+            except IncompatibleConstraintError:
+                logger.info(self._version_conflict_information(
+                    requirement.project_name.lower()))
+                raise
+
         return requirement
 
     def install(self, specs, working_set=None):
 
         logger.debug('Installing %s.', repr(specs)[1:-1])
+        self._requirements_and_constraints.append(
+            "Base installation request: %s" % repr(specs)[1:-1])
 
         for_buildout_run = bool(working_set)
         path = self._path
@@ -688,11 +716,17 @@ class Installer:
                     self._maybe_add_setuptools(ws, dist)
             if dist not in req:
                 # Oops, the "best" so far conflicts with a dependency.
+                logger.info(self._version_conflict_information(req.key))
                 raise VersionConflict(
                     pkg_resources.VersionConflict(dist, req), ws)
 
             best[req.key] = dist
-            requirements.extend(dist.requires(req.extras)[::-1])
+            extra_requirements = dist.requires(req.extras)[::-1]
+            for extra_requirement in extra_requirements:
+                self._requirements_and_constraints.append(
+                    "Requirement of %s: %s" % (current_requirement, extra_requirement))
+            requirements.extend(extra_requirements)
+
             processed[req] = True
         return ws
 
@@ -1505,7 +1539,9 @@ def _constrained_requirement(constraint, requirement):
             assert constraint.startswith('==')
             constraint = constraint[2:]
         if constraint not in requirement:
-            bad_constraint(constraint, requirement)
+            msg = ("The requirement (%r) is not allowed by your [versions] "
+                   "constraint (%s)" % (str(requirement), constraint))
+            raise IncompatibleConstraintError(msg)
 
         # Sigh, copied from Requirement.__str__
         extras = ','.join(requirement.extras)
@@ -1528,8 +1564,3 @@ class IncompatibleConstraintError(zc.buildout.UserError):
     """
 
 IncompatibleVersionError = IncompatibleConstraintError # Backward compatibility
-
-def bad_constraint(constraint, requirement):
-    logger.error("The constraint, %s, is not consistent with the "
-                 "requirement, %r.", constraint, str(requirement))
-    raise IncompatibleConstraintError("Bad constraint", constraint, requirement)

src/zc/buildout/easy_install.txt

@@ -242,13 +242,15 @@ we'll get an error:
     ...     versions = dict(demo='0.2', demoneeded='1.0'))
     Traceback (most recent call last):
     ...
-    IncompatibleConstraintError: Bad constraint 0.2 demo>0.2
+    IncompatibleConstraintError: The requirement ('demo>0.2') is not allowed by your [versions] constraint (0.2)
 
     >>> print_(handler)
     zc.buildout.easy_install DEBUG
       Installing 'demo >0.2'.
-    zc.buildout.easy_install ERROR
-      The constraint, 0.2, is not consistent with the requirement, 'demo>0.2'.
+    zc.buildout.easy_install INFO
+      Version and requirements information containing demo:
+      [versions] constraint on demo: 0.2
+      Base installation request: 'demo >0.2'
 
     >>> handler.clear()
 

src/zc/buildout/tests.py

@@ -306,6 +306,9 @@ Now, let's create a buildout that requires y and z:
     Installing eggs.
     Getting distribution for 'demoneeded==1.1'.
     Got demoneeded 1.1.
+    Version and requirements information containing demoneeded:
+      Requirement of samplez: demoneeded==1.1
+      Requirement of sampley: demoneeded==1.0
     While:
       Installing eggs.
     Error: There is a version conflict.
@@ -355,6 +358,9 @@ If we use the verbose switch, we can see where requirements are coming from:
     Getting required 'sampley'
       required by sampleb 1.
     We have a develop egg: sampley 1
+    Version and requirements information containing demoneeded:
+      Requirement of samplez: demoneeded==1.1
+      Requirement of sampley: demoneeded==1.0
     While:
       Installing eggs.
     Error: There is a version conflict.