diff --git a/bitbake/lib/bb/cache.py b/bitbake/lib/bb/cache.py
index 619b9ee..a3c073a 100644
--- a/bitbake/lib/bb/cache.py
+++ b/bitbake/lib/bb/cache.py
@@ -405,12 +405,12 @@ class Cache(object):
         """Parse the specified filename, returning the recipe information"""
         infos = []
         datastores = cls.load_bbfile(filename, appends, configdata)
-        depends = set()
+        depends = []
         for variant, data in sorted(datastores.iteritems(),
                                     key=lambda i: i[0],
                                     reverse=True):
             virtualfn = cls.realfn2virtual(filename, variant)
-            depends |= (data.getVar("__depends", False) or set())
+            depends = depends + (data.getVar("__depends", False) or [])
             if depends and not variant:
                 data.setVar("__depends", depends)
 
diff --git a/bitbake/lib/bb/cooker.py b/bitbake/lib/bb/cooker.py
index e299059..98d6957 100644
--- a/bitbake/lib/bb/cooker.py
+++ b/bitbake/lib/bb/cooker.py
@@ -692,8 +692,8 @@ class BBCooker:
         # Generate a list of parsed configuration files by searching the files
         # listed in the __depends and __base_depends variables with a .conf suffix.
         conffiles = []
-        dep_files = self.configuration.data.getVar('__depends') or set()
-        dep_files.union(self.configuration.data.getVar('__base_depends') or set())
+        dep_files = self.configuration.data.getVar('__base_depends') or []
+        dep_files = dep_files + (self.configuration.data.getVar('__depends') or [])
 
         for f in dep_files:
             if f[0].endswith(".conf"):
diff --git a/bitbake/lib/bb/parse/__init__.py b/bitbake/lib/bb/parse/__init__.py
index 7b9c47e..4293d09c 100644
--- a/bitbake/lib/bb/parse/__init__.py
+++ b/bitbake/lib/bb/parse/__init__.py
@@ -73,8 +73,7 @@ def update_mtime(f):
 def mark_dependency(d, f):
     if f.startswith('./'):
         f = "%s/%s" % (os.getcwd(), f[2:])
-    deps = d.getVar('__depends') or set()
-    deps.update([(f, cached_mtime(f))])
+    deps = (d.getVar('__depends') or []) + [(f, cached_mtime(f))]
     d.setVar('__depends', deps)
 
 def supports(fn, data):
@@ -134,8 +133,8 @@ def vars_from_file(mypkg, d):
 def get_file_depends(d):
     '''Return the dependent files'''
     dep_files = []
-    depends = d.getVar('__depends', True) or set()
-    depends = depends.union(d.getVar('__base_depends', True) or set())
+    depends = d.getVar('__base_depends', True) or []
+    depends = depends + (d.getVar('__depends', True) or [])
     for (fn, _) in depends:
         dep_files.append(os.path.abspath(fn))
     return " ".join(dep_files)