diff --git a/changelog/1495.doc.rst b/changelog/1495.doc.rst
new file mode 100644
index 000000000..ab7231333
--- /dev/null
+++ b/changelog/1495.doc.rst
@@ -0,0 +1 @@
+Document common doctest fixture directory tree structure pitfalls
diff --git a/changelog/4265.bugfix.rst b/changelog/4265.bugfix.rst
new file mode 100644
index 000000000..7b40737c3
--- /dev/null
+++ b/changelog/4265.bugfix.rst
@@ -0,0 +1 @@
+Validate arguments from the ``PYTEST_ADDOPTS`` environment variable and the ``addopts`` ini option separately.
diff --git a/changelog/4500.bugfix.rst b/changelog/4500.bugfix.rst
new file mode 100644
index 000000000..b84b6b117
--- /dev/null
+++ b/changelog/4500.bugfix.rst
@@ -0,0 +1 @@
+When a fixture yields and a log call is made after the test runs, and, if the test is interrupted, capture attributes are ``None``.
diff --git a/doc/en/doctest.rst b/doc/en/doctest.rst
index 52edd4cf2..125ed3aa7 100644
--- a/doc/en/doctest.rst
+++ b/doc/en/doctest.rst
@@ -154,6 +154,9 @@ which can then be used in your doctests directly::
         """
         pass
 
+Note that like the normal ``conftest.py``, the fixtures are discovered in the directory tree conftest is in.
+Meaning that if you put your doctest with your source code, the relevant conftest.py needs to be in the same directory tree.
+Fixtures will not be discovered in a sibling directory tree!
 
 Output format
 -------------
diff --git a/doc/en/mark.rst b/doc/en/mark.rst
index 5d1cd00f4..d5c5c5735 100644
--- a/doc/en/mark.rst
+++ b/doc/en/mark.rst
@@ -156,4 +156,4 @@ More details can be found in the `original PR <https://github.com/pytest-dev/pyt
 .. note::
 
     in a future major relase of pytest we will introduce class based markers,
-    at which points markers will no longer be limited to instances of :py:class:`Mark`
+    at which point markers will no longer be limited to instances of :py:class:`Mark`
diff --git a/doc/en/requirements.txt b/doc/en/requirements.txt
index b9fdcb8f6..80c57422f 100644
--- a/doc/en/requirements.txt
+++ b/doc/en/requirements.txt
@@ -1,5 +1,3 @@
-pygments-pytest>=1.0.4
-# pinning sphinx to 1.4.* due to search issues with rtd:
-# https://github.com/rtfd/readthedocs-sphinx-ext/issues/25
-sphinx ==1.4.*
+pygments-pytest>=1.1.0
+sphinx>=1.8.2
 sphinxcontrib-trio
diff --git a/src/_pytest/capture.py b/src/_pytest/capture.py
index 679eb4d16..533690949 100644
--- a/src/_pytest/capture.py
+++ b/src/_pytest/capture.py
@@ -117,7 +117,10 @@ class CaptureManager(object):
             self._global_capturing = None
 
     def resume_global_capture(self):
-        self._global_capturing.resume_capturing()
+        # During teardown of the python process, and on rare occasions, capture
+        # attributes can be `None` while trying to resume global capture.
+        if self._global_capturing is not None:
+            self._global_capturing.resume_capturing()
 
     def suspend_global_capture(self, in_=False):
         cap = getattr(self, "_global_capturing", None)
diff --git a/src/_pytest/config/__init__.py b/src/_pytest/config/__init__.py
index 1897f523b..13944099c 100644
--- a/src/_pytest/config/__init__.py
+++ b/src/_pytest/config/__init__.py
@@ -777,12 +777,21 @@ class Config(object):
         for name in _iter_rewritable_modules(package_files):
             hook.mark_rewrite(name)
 
+    def _validate_args(self, args):
+        """Validate known args."""
+        self._parser.parse_known_and_unknown_args(
+            args, namespace=copy.copy(self.option)
+        )
+        return args
+
     def _preparse(self, args, addopts=True):
         if addopts:
-            args[:] = shlex.split(os.environ.get("PYTEST_ADDOPTS", "")) + args
+            env_addopts = os.environ.get("PYTEST_ADDOPTS", "")
+            if len(env_addopts):
+                args[:] = self._validate_args(shlex.split(env_addopts)) + args
         self._initini(args)
         if addopts:
-            args[:] = self.getini("addopts") + args
+            args[:] = self._validate_args(self.getini("addopts")) + args
         self._checkversion()
         self._consider_importhook(args)
         self.pluginmanager.consider_preparse(args)
diff --git a/testing/python/raises.py b/testing/python/raises.py
index e3a0c4a05..52ad6cfa6 100644
--- a/testing/python/raises.py
+++ b/testing/python/raises.py
@@ -197,7 +197,8 @@ class TestRaises(object):
             pass
 
         with pytest.raises(
-            Failed, match="DID NOT RAISE <class 'raises.ClassLooksIterableException'>"
+            Failed,
+            match=r"DID NOT RAISE <class 'raises(\..*)*ClassLooksIterableException'>",
         ):
             pytest.raises(ClassLooksIterableException, lambda: None)
 
diff --git a/testing/test_capture.py b/testing/test_capture.py
index 17bb82967..43cd700d3 100644
--- a/testing/test_capture.py
+++ b/testing/test_capture.py
@@ -302,14 +302,14 @@ class TestLoggingInteraction(object):
             """\
             import logging
             def setup_function(function):
-                logging.warn("hello1")
+                logging.warning("hello1")
 
             def test_logging():
-                logging.warn("hello2")
+                logging.warning("hello2")
                 assert 0
 
             def teardown_function(function):
-                logging.warn("hello3")
+                logging.warning("hello3")
                 assert 0
             """
         )
@@ -328,14 +328,14 @@ class TestLoggingInteraction(object):
             """\
             import logging
             def setup_module(function):
-                logging.warn("hello1")
+                logging.warning("hello1")
 
             def test_logging():
-                logging.warn("hello2")
+                logging.warning("hello2")
                 assert 0
 
             def teardown_module(function):
-                logging.warn("hello3")
+                logging.warning("hello3")
                 assert 0
             """
         )
@@ -354,7 +354,7 @@ class TestLoggingInteraction(object):
             """\
                 import logging
                 logging.basicConfig()
-                logging.warn("hello435")
+                logging.warning("hello435")
             """
         )
         # make sure that logging is still captured in tests
@@ -375,7 +375,7 @@ class TestLoggingInteraction(object):
             """\
             def test_hello():
                 import logging
-                logging.warn("hello433")
+                logging.warning("hello433")
                 assert 0
             """
         )
@@ -385,6 +385,40 @@ class TestLoggingInteraction(object):
         assert "something" not in result.stderr.str()
         assert "operation on closed file" not in result.stderr.str()
 
+    def test_logging_after_cap_stopped(self, testdir):
+        testdir.makeconftest(
+            """\
+                import pytest
+                import logging
+
+                log = logging.getLogger(__name__)
+
+                @pytest.fixture
+                def log_on_teardown():
+                    yield
+                    log.warning('Logging on teardown')
+            """
+        )
+        # make sure that logging is still captured in tests
+        p = testdir.makepyfile(
+            """\
+            def test_hello(log_on_teardown):
+                import logging
+                logging.warning("hello433")
+                assert 1
+                raise KeyboardInterrupt()
+            """
+        )
+        result = testdir.runpytest_subprocess(p, "--log-cli-level", "info")
+        assert result.ret != 0
+        result.stdout.fnmatch_lines(
+            ["*WARNING*hello433*", "*WARNING*Logging on teardown*"]
+        )
+        assert (
+            "AttributeError: 'NoneType' object has no attribute 'resume_capturing'"
+            not in result.stderr.str()
+        )
+
 
 class TestCaptureFixture(object):
     @pytest.mark.parametrize("opt", [[], ["-s"]])
@@ -1300,13 +1334,13 @@ def test_capturing_and_logging_fundamentals(testdir, method):
                                      Capture=capture.%s)
         cap.start_capturing()
 
-        logging.warn("hello1")
+        logging.warning("hello1")
         outerr = cap.readouterr()
         print("suspend, captured %%s" %%(outerr,))
-        logging.warn("hello2")
+        logging.warning("hello2")
 
         cap.pop_outerr_to_orig()
-        logging.warn("hello3")
+        logging.warning("hello3")
 
         outerr = cap.readouterr()
         print("suspend2, captured %%s" %% (outerr,))
diff --git a/testing/test_config.py b/testing/test_config.py
index fcb886d53..012b8936c 100644
--- a/testing/test_config.py
+++ b/testing/test_config.py
@@ -1083,6 +1083,33 @@ class TestOverrideIniArgs(object):
         config._preparse([], addopts=True)
         assert config._override_ini == ["cache_dir=%s" % cache_dir]
 
+    def test_addopts_from_env_not_concatenated(self, monkeypatch):
+        """PYTEST_ADDOPTS should not take values from normal args (#4265)."""
+        from _pytest.config import get_config
+
+        monkeypatch.setenv("PYTEST_ADDOPTS", "-o")
+        config = get_config()
+        with pytest.raises(SystemExit) as excinfo:
+            config._preparse(["cache_dir=ignored"], addopts=True)
+        assert excinfo.value.args[0] == _pytest.main.EXIT_USAGEERROR
+
+    def test_addopts_from_ini_not_concatenated(self, testdir):
+        """addopts from ini should not take values from normal args (#4265)."""
+        testdir.makeini(
+            """
+            [pytest]
+            addopts=-o
+        """
+        )
+        result = testdir.runpytest("cache_dir=ignored")
+        result.stderr.fnmatch_lines(
+            [
+                "%s: error: argument -o/--override-ini: expected one argument"
+                % (testdir.request.config._parser.optparser.prog,)
+            ]
+        )
+        assert result.ret == _pytest.main.EXIT_USAGEERROR
+
     def test_override_ini_does_not_contain_paths(self):
         """Check that -o no longer swallows all options after it (#3103)"""
         from _pytest.config import get_config