Remove dead imports and other things found by PyChecker.

3 files changed, 20 insertions, 19 deletions

diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index 13a2f52..1863d93 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -1243,7 +1243,7 @@ class Dir(Base):
         """A null "builder" for directories."""
         return []
 
-    def build(self):
+    def build(self, **kw):
         """A null "builder" for directories."""
         pass
 
@@ -1673,12 +1673,12 @@ class File(Base):
 
         if calc.max_drift >= 0 and (time.time() - mtime) > calc.max_drift:
             try:
-                self.binfo
+                binfo = self.binfo
             except AttributeError:
-                self.binfo = self.new_binfo()
-            self.binfo.csig = csig
-            self.binfo.timestamp = mtime
-            self.store_info(self.binfo)
+                binfo = self.binfo = self.new_binfo()
+            binfo.csig = csig
+            binfo.timestamp = mtime
+            self.store_info(binfo)
 
         return csig
 
diff --git a/src/engine/SCons/Node/Python.py b/src/engine/SCons/Node/Python.py
index a2537ae..e15888b 100644
--- a/src/engine/SCons/Node/Python.py
+++ b/src/engine/SCons/Node/Python.py
@@ -67,12 +67,12 @@ class Value(SCons.Node.Node):
         timestamp, we get to ignore the calculator and just use the
         value contents."""
         try:
-            self.binfo
+            binfo = self.binfo
         except:
-            self.binfo = self.new_binfo()
+            binfo = self.binfo = self.new_binfo()
         try:
-            return self.binfo.csig
+            return binfo.csig
         except AttributeError:
-            self.binfo.csig = self.get_contents()
-            self.store_info(self.binfo)
-            return self.binfo.csig
+            binfo.csig = self.get_contents()
+            self.store_info(binfo)
+            return binfo.csig
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index 66e1420..24c70b8 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -549,15 +549,15 @@ class Node:
 
     def calc_csig(self, calc):
         try:
-            self.binfo
-        except:
-            self.binfo = self.new_binfo()
+            binfo = self.binfo
+        except AttributeError:
+            binfo = self.binfo = self.new_binfo()
         try:
-            return self.binfo.csig
+            return binfo.csig
         except AttributeError:
-            self.binfo.csig = calc.module.signature(self)
-            self.store_info(self.binfo)
-            return self.binfo.csig
+            binfo.csig = calc.module.signature(self)
+            self.store_info(binfo)
+            return binfo.csig
 
     def store_info(self, obj):
         """Make the build signature permanent (that is, store it in the
@@ -930,6 +930,7 @@ class Walker:
                         parent = None
                     self.eval_func(node, parent)
                 return node
+        return None
 
     def is_done(self):
         return not self.stack