Fix issue 2985.

AUTHORS

@@ -74,6 +74,7 @@ Grig Gheorghiu
 Grigorii Eremeev (budulianin)
 Guido Wesdorp
 Harald Armin Massa
+Henk-Jaap Wagenaar
 Hugo van Kemenade
 Hui Wang (coldnight)
 Ian Bicking

_pytest/main.py

@@ -728,23 +728,64 @@ def _tryconvertpyarg(self, x):
         """Convert a dotted module name to path.
 
         """
-        import pkgutil
-        try:
-            loader = pkgutil.find_loader(x)
-        except ImportError:
-            return x
-        if loader is None:
-            return x
-        # This method is sometimes invoked when AssertionRewritingHook, which
-        # does not define a get_filename method, is already in place:
-        try:
-            path = loader.get_filename(x)
-        except AttributeError:
-            # Retrieve path from AssertionRewritingHook:
-            path = loader.modules[x][0].co_filename
-        if loader.is_package(x):
-            path = os.path.dirname(path)
-        return path
+        if six.PY2:
+            # this is deprecated in python 3.4 and above
+            import pkgutil
+
+            def find_module_patched(self, fullname, path=None):
+                subname = fullname.split(".")[-1]
+                if subname != fullname and self.path is None:
+                    return None
+                if self.path is None:
+                    path = None
+                else:
+                    path = [self.path]
+                try:
+                    file, filename, etc = pkgutil.imp.find_module(subname,
+                                                                  path)
+                except ImportError:
+                    return None
+                return pkgutil.ImpLoader(fullname, file, filename, etc)
+
+            pkgutil.ImpImporter.find_module = find_module_patched
+
+            try:
+                loader = pkgutil.find_loader(x)
+            except ImportError:
+                return x
+            if loader is None:
+                return x
+            # This method is sometimes invoked when AssertionRewritingHook, which
+            # does not define a get_filename method, is already in place:
+            try:
+                path = loader.get_filename(x)
+            except AttributeError:
+                # Retrieve path from AssertionRewritingHook:
+                path = loader.modules[x][0].co_filename
+            if loader.is_package(x):
+                path = os.path.dirname(path)
+            return path
+        else:
+            # this is not available (even as backport) for python 2.7
+            import importlib.util
+
+            try:
+                spec = importlib.util.find_spec(x)
+            except (
+                ImportError,  # import failed
+                AttributeError,  # parent not package
+                ValueError  # (invalid) relative import
+            ):
+                return x
+
+            if spec is None:
+                return x
+            elif spec.submodule_search_locations:  # if package
+                return os.path.dirname(spec.origin)
+            elif spec.has_location:  # origin is a valid location
+                return spec.origin
+            else:  # the import might have involved AssertionRewritingHook
+                return spec.loader.modules[x][0].co_filename
 
     def _parsearg(self, arg):
         """ return (fspath, names) tuple after checking the file exists. """

changelog/2985.bugfix

@@ -0,0 +1 @@
+Fix conversion of pyargs to filename to not convert symlinks and not use deprecated features on Python 3.

testing/acceptance_test.py

@@ -3,6 +3,8 @@
 import os
 import sys
 
+import six
+
 import _pytest._code
 import py
 import pytest
@@ -645,6 +647,68 @@ def join_pythonpath(*dirs):
             "*1 passed*"
         ])
 
+    def test_cmdline_python_package_symlink(self, testdir, monkeypatch):
+        """
+        test --pyargs option with packages with path containing symlink can
+        have conftest.py in their package (#2985)
+        """
+        monkeypatch.delenv('PYTHONDONTWRITEBYTECODE', raising=False)
+
+        search_path = ["lib", os.path.join("local", "lib")]
+
+        dirname = "lib"
+        d = testdir.mkdir(dirname)
+        foo = d.mkdir("foo")
+        foo.ensure("__init__.py")
+        lib = foo.mkdir('bar')
+        lib.ensure("__init__.py")
+        lib.join("test_bar.py"). \
+            write("def test_bar(): pass\n"
+                  "def test_other(a_fixture):pass")
+        lib.join("conftest.py"). \
+            write("import pytest\n"
+                  "@pytest.fixture\n"
+                  "def a_fixture():pass")
+
+        d_local = testdir.mkdir("local")
+        symlink_location = os.path.join(str(d_local), "lib")
+        if six.PY2:
+            os.symlink(str(d), symlink_location)
+        else:
+            os.symlink(str(d), symlink_location, target_is_directory=True)
+
+        # The structure of the test directory is now:
+        # .
+        # ├── local
+        # │   └── lib -> ../world
+        # └── lib
+        #     └── foo
+        #         ├── __init__.py
+        #         └── bar
+        #             ├── __init__.py
+        #             ├── conftest.py
+        #             └── test_world.py
+
+        def join_pythonpath(*dirs):
+            cur = py.std.os.environ.get('PYTHONPATH')
+            if cur:
+                dirs += (cur,)
+            return os.pathsep.join(str(p) for p in dirs)
+
+        monkeypatch.setenv('PYTHONPATH', join_pythonpath(*search_path))
+        for p in search_path:
+            monkeypatch.syspath_prepend(p)
+        print(sys.path)
+        # module picked up in symlinked directory:
+        result = testdir.runpytest("--pyargs", "-v", "foo.bar")
+        testdir.chdir()
+        assert result.ret == 0
+        result.stdout.fnmatch_lines([
+            "*lib/foo/bar/test_bar.py::test_bar*PASSED*",
+            "*lib/foo/bar/test_bar.py::test_other*PASSED*",
+            "*2 passed*"
+        ])
+
     def test_cmdline_python_package_not_exists(self, testdir):
         result = testdir.runpytest("--pyargs", "tpkgwhatv")
         assert result.ret