From 6fce1f0ac7a9a569429efa740f5cdd04805b4a6c Mon Sep 17 00:00:00 2001
From: Daniel Hahler <git@thequod.de>
Date: Wed, 7 Nov 2018 20:06:35 +0100
Subject: [PATCH] pkg_roots per session

---
 src/_pytest/main.py | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/_pytest/main.py b/src/_pytest/main.py
index 50bd10979..5d5d02a23 100644
--- a/src/_pytest/main.py
+++ b/src/_pytest/main.py
@@ -386,6 +386,7 @@ class Session(nodes.FSCollector):
         self._initialpaths = frozenset()
         # Keep track of any collected nodes in here, so we don't duplicate fixtures
         self._node_cache = {}
+        self._pkg_roots = {}
 
         self.config.pluginmanager.register(self, name="session")
 
@@ -488,7 +489,6 @@ class Session(nodes.FSCollector):
 
         names = self._parsearg(arg)
         argpath = names.pop(0).realpath()
-        pkg_roots = {}
 
         root = self
         # Start with a Session root, and delve to argpath item (dir or file)
@@ -509,7 +509,7 @@ class Session(nodes.FSCollector):
                             col = root._collectfile(pkginit, handle_dupes=False)
                             if col:
                                 if isinstance(col[0], Package):
-                                    pkg_roots[parent] = col[0]
+                                    self._pkg_roots[parent] = col[0]
                                 # always store a list in the cache, matchnodes expects it
                                 self._node_cache[col[0].fspath] = [col[0]]
 
@@ -533,15 +533,25 @@ class Session(nodes.FSCollector):
                 fil=filter_, rec=self._recurse, bf=True, sort=True
             ):
                 dirpath = path.dirpath()
-                collect_root = pkg_roots.get(dirpath, root)
+                collect_root = self._pkg_roots.get(dirpath, root)
                 if dirpath not in seen_dirs:
+                    # Collect packages first.
                     seen_dirs.add(dirpath)
                     pkginit = dirpath.join("__init__.py")
                     if pkginit.exists():
+                        got_pkg = False
                         for x in collect_root._collectfile(pkginit):
                             yield x
                             if isinstance(x, Package):
-                                pkg_roots[dirpath] = x
+                                self._pkg_roots[dirpath] = x
+                                got_pkg = True
+                        if got_pkg:
+                            continue
+                if path.basename == "__init__.py":
+                    continue
+
+                if dirpath in self._pkg_roots:
+                    continue
 
                 for x in collect_root._collectfile(path):
                     key = (type(x), x.fspath)
@@ -556,7 +566,7 @@ class Session(nodes.FSCollector):
             if argpath in self._node_cache:
                 col = self._node_cache[argpath]
             else:
-                collect_root = pkg_roots.get(argpath.dirname, root)
+                collect_root = self._pkg_roots.get(argpath.dirname, root)
                 col = collect_root._collectfile(argpath)
                 if col:
                     self._node_cache[argpath] = col