Merge branch 'hotfix/v3.5.5' into develop

* hotfix/v3.5.5:
  Fix an issue when "srcFilter" field in "library.json" breaks a library build // Resolve #1735
  Fix "test_lib" test

HISTORY.rst

@@ -31,6 +31,10 @@ PlatformIO 3.0
   - Force building of project source code using `test_build_project_src <http://docs.platformio.org/page/projectconf/section_env_test.html#test_build_project_src>`__ option
   - Fixed missed ``UNIT_TEST`` macro for unit test components/libraries
 
+* Fixed an issue when ``srcFilter`` field in `library.json <http://docs.platformio.org/page/librarymanager/config.html>`__
+  breaks a library build
+  (`issue #1735 <https://github.com/platformio/platformio-core/issues/1735>`_)
+
 3.5.4 (2018-07-03)
 ~~~~~~~~~~~~~~~~~~
 

platformio/builder/tools/piolib.py

@@ -586,15 +586,6 @@ class PlatformIOLibBuilder(LibBuilderBase):
     def _is_arduino_manifest(self):
         return isfile(join(self.path, "library.properties"))
 
-    @property
-    def src_dir(self):
-        if all([
-                "srcFilter" in self._manifest.get("build", {})
-                or self.env['SRC_FILTER'], not self._is_arduino_manifest()
-        ]):
-            return self.path
-        return LibBuilderBase.src_dir.fget(self)
-
     @property
     def src_filter(self):
         if "srcFilter" in self._manifest.get("build", {}):