Merge pull request #191 from mottosso/master

Fixed #106

pyblish/plugin.py

@@ -878,11 +878,18 @@ def discover(type=None, regex=None, paths=None):
                 continue
 
             mod_name, _ = os.path.splitext(fname)
+
+            try:
+                # Discard traces of previously
+                # imported modules of this name.
+                sys.modules.pop(mod_name)
+            except:
+                pass
+
             try:
                 sys.path.insert(0, path)
                 module = pyblish.lib.import_module(mod_name)
                 reload(module)
-
             except Exception as err:
                 log.warning("Skipped: \"%s\" (%s)", mod_name, err)
                 continue

tests/test_plugin.py

@@ -1,6 +1,22 @@
+import os
+import shutil
+import tempfile
+import contextlib
+
 import pyblish.plugin
 from pyblish.vendor.nose.tools import *
 
+import lib
+
+
+@contextlib.contextmanager
+def tempdir():
+    try:
+        tempdir = tempfile.mkdtemp()
+        yield tempdir
+    finally:
+        shutil.rmtree(tempdir)
+
 
 def test_unique_id():
     """Plug-ins and instances have a unique id"""
@@ -47,3 +63,58 @@ def test_asset():
 
     assert_true(asseta in context)
     assert_true(assetb in context)
+
+
+@with_setup(lib.setup_empty, lib.teardown)
+def test_import_mechanism_duplication():
+    """Plug-ins don't linger after a second discovery
+
+    E.g. when changing the name of a plug-in and then rediscover
+    the previous plug-ins is still around.
+
+    """
+
+    with tempdir() as temp:
+        print("Writing temporarily to: %s" % temp)
+        module = os.path.join(temp, "selector.py")
+        pyblish.api.register_plugin_path(temp)
+
+        with open(module, "w") as f:
+            f.write("""
+import pyblish.api
+
+class MySelector(pyblish.api.Selector):
+    pass
+""")
+
+        with open(module) as f:
+            print("File contents after first write:")
+            print(f.read())
+
+        # MySelector should be accessible by now
+        plugins = [p.__name__ for p in pyblish.api.discover()]
+
+        assert "MySelector" in plugins, plugins
+        assert "MyOtherSelector" not in plugins, plugins
+
+        # Remove module, and it's .pyc equivalent
+        [os.remove(os.path.join(temp, fname))
+         for fname in os.listdir(temp)]
+
+        with open(module, "w") as f:
+            f.write("""
+import pyblish.api
+
+class MyOtherSelector(pyblish.api.Selector):
+    pass
+""")
+
+        with open(module) as f:
+            print("File contents after second write:")
+            print(f.read())
+
+        # MySelector should be gone in favour of MyOtherSelector
+        plugins = [p.__name__ for p in pyblish.api.discover()]
+
+        assert "MyOtherSelector" in plugins, plugins
+        assert "MySelector" not in plugins, plugins