warn about invalid python prefix data, instead of erroring out

conda/core/prefix_data.py

@@ -8,6 +8,7 @@
 from os import listdir
 from os.path import basename, isdir, isfile, join, lexists
 
+from .._vendor.auxlib.exceptions import ValidationError
 from ..base.constants import CONDA_TARBALL_EXTENSION, PREFIX_MAGIC_FILE
 from ..base.context import context
 from ..common.compat import JSONDecodeError, itervalues, odict, string_types, with_metaclass
@@ -257,6 +258,16 @@ def _load_site_packages(self):
                 python_record = read_python_record(self.prefix_path, af, python_pkg_record.version)
             except EnvironmentError:
                 continue
+            except ValidationError:
+                import sys
+                exc_type, exc_value, exc_traceback = sys.exc_info()
+                import traceback
+                tb = traceback.format_exception(exc_type, exc_value, exc_traceback)
+                log.warn("Problem reading non-conda package record at %s. Please verify that you "
+                         "still need this, and if so, that this is still installed correctly. "
+                         "Reinstalling this package may help.", af)
+                log.debug("ValidationError: \n%s\n", "\n".join(tb))
+                continue
             if not python_record:
                 continue
             self.__prefix_records[python_record.name] = python_record

setup.cfg

@@ -34,7 +34,7 @@ exclude = build/*,.tox/*,env/*,test_data/*,tests/*,ve/*,utils/*,*/_vendor/*,cond
 [flake8]
 max-line-length = 99
 ignore = E126,E133,E226,E241,E242,E302,E704,E731,E722,W503
-exclude = build/*,.tox/*,devenv/*,env/*,test_data/*,tests/*,ve/*,utils/*,*/_vendor/*,conda/compat.py,conda/common/compat.py,conda_env/compat.py
+exclude = .asv*,build/*,.tox/*,devenv/*,env/*,test_data/*,tests/*,ve/*,utils/*,*/_vendor/*,conda/compat.py,conda/common/compat.py,conda_env/compat.py
 
 
 [coverage:report]