Refactor env.Append() and env.Prepend().

2 files changed, 98 insertions, 42 deletions

diff --git a/src/engine/SCons/Environment.py b/src/engine/SCons/Environment.py
index dc52ee1..1d61ae8 100644
--- a/src/engine/SCons/Environment.py
+++ b/src/engine/SCons/Environment.py
@@ -454,26 +454,53 @@ class Base:
         in an Environment.
         """
         kw = our_deepcopy(kw)
-        for key in kw.keys():
-            if not self._dict.has_key(key):
-                self._dict[key] = kw[key]
-            elif SCons.Util.is_List(self._dict[key]) and not \
-                 SCons.Util.is_List(kw[key]):
-                if kw[key]:
-                    self._dict[key] = self._dict[key] + [ kw[key] ]
-                #self._dict[key] = map(None, self._dict[key] + [ kw[key] ])
-            elif SCons.Util.is_List(kw[key]) and not \
-                 SCons.Util.is_List(self._dict[key]):
-                if self._dict[key]:
-                    self._dict[key] = [ self._dict[key] ] + kw[key]
-                else:
-                    self._dict[key] = kw[key]
-                #self._dict[key] = map(None, self._dict[key] + [ kw[key] ])
-            elif SCons.Util.is_Dict(self._dict[key]) and \
-                 SCons.Util.is_Dict(kw[key]):
-                self._dict[key].update(kw[key])
+        for key, val in kw.items():
+            try:
+                orig = self._dict[key]
+            except KeyError:
+                # No existing variable in the environment, so just set
+                # it to the new value.
+                self._dict[key] = val
+                continue
+
+            try:
+                # Most straightforward:  just try to add them together.
+                # This will work in most cases, when the original and
+                # new values are of compatible types.
+                self._dict[key] = orig + val
+                continue
+            except TypeError:
+                pass
+
+            try:
+                # Try to update a dictionary value with another.
+                # If orig isn't a dictionary, it won't have an
+                # update() method; if val isn't a dictionary, it
+                # won't have a keys() method.  Either way, it's
+                # an AttributeError.
+                orig.update(val)
+                continue
+            except AttributeError:
+                pass
+
+            try:
+                # Check if the original is a list.
+                add_to_orig = orig.append
+            except AttributeError:
+                pass
             else:
-                self._dict[key] = self._dict[key] + kw[key]
+                # The original is a list, so append the new value to it
+                # (if there's a value to append).
+                if val:
+                    add_to_orig(val)
+                continue
+
+            # The original isn't a list, but the new value is (by process
+            # of elimination), so insert the original in the new value
+            # (if there's one to insert) and replace the variable with it.
+            if orig:
+                val.insert(0, orig)
+            self._dict[key] = val
 
     def AppendENVPath(self, name, newpath, envname = 'ENV', sep = os.pathsep):
         """Append path elements to the path 'name' in the 'ENV'
@@ -662,24 +689,53 @@ class Base:
         in an Environment.
         """
         kw = our_deepcopy(kw)
-        for key in kw.keys():
-            if not self._dict.has_key(key):
-                self._dict[key] = kw[key]
-            elif SCons.Util.is_List(self._dict[key]) and not \
-                 SCons.Util.is_List(kw[key]):
-                if kw[key]:
-                    self._dict[key] = [ kw[key] ] + self._dict[key]
-            elif SCons.Util.is_List(kw[key]) and not \
-                 SCons.Util.is_List(self._dict[key]):
-                if self._dict[key]:
-                    self._dict[key] = kw[key] + [ self._dict[key] ]
-                else:
-                    self._dict[key] = kw[key]
-            elif SCons.Util.is_Dict(self._dict[key]) and \
-                 SCons.Util.is_Dict(kw[key]):
-                self._dict[key].update(kw[key])
+        for key, val in kw.items():
+            try:
+                orig = self._dict[key]
+            except KeyError:
+                # No existing variable in the environment, so just set
+                # it to the new value.
+                self._dict[key] = val
+                continue
+
+            try:
+                # Most straightforward:  just try to add them together.
+                # This will work in most cases, when the original and
+                # new values are of compatible types.
+                self._dict[key] = val + orig
+                continue
+            except TypeError:
+                pass
+
+            try:
+                # Try to update a dictionary value with another.
+                # If orig isn't a dictionary, it won't have an
+                # update() method; if val isn't a dictionary, it
+                # won't have a keys() method.  Either way, it's
+                # an AttributeError.
+                orig.update(val)
+                continue
+            except AttributeError:
+                pass
+
+            try:
+                # Check if the added value is a list.
+                add_to_val = val.append
+            except AttributeError:
+                pass
             else:
-                self._dict[key] = kw[key] + self._dict[key]
+                # The added value is a list, so append the original to it
+                # (if there's a value to append).
+                if orig:
+                    add_to_val(orig)
+                self._dict[key] = val
+                continue
+
+            # The added value isn't a list, but the original is (by
+            # process of elimination), so insert the the new value in
+            # the original (if there's one to insert).
+            if val:
+                orig.insert(0, val)
 
     def PrependENVPath(self, name, newpath, envname = 'ENV', sep = os.pathsep):
         """Prepend path elements to the path 'name' in the 'ENV'
diff --git a/src/engine/SCons/EnvironmentTests.py b/src/engine/SCons/EnvironmentTests.py
index 0576f83..11fd0d8 100644
--- a/src/engine/SCons/EnvironmentTests.py
+++ b/src/engine/SCons/EnvironmentTests.py
@@ -875,7 +875,7 @@ class EnvironmentTestCase(unittest.TestCase):
             ['e7'],     [''],           ['e7', ''],
             ['e8'],     UL(['']),       UL(['e8', '']),
 
-            UL(['i1']), 'I1',           UL(['i1', 'I1']),
+            UL(['i1']), 'I1',           UL(['i1', 'I', '1']),
             UL(['i2']), ['I2'],         UL(['i2', 'I2']),
             UL(['i3']), UL(['I3']),     UL(['i3', 'I3']),
             UL(['i4']), '',             UL(['i4']),
@@ -902,7 +902,7 @@ class EnvironmentTestCase(unittest.TestCase):
             [],         [''],           [''],
             [],         UL(['']),       UL(['']),
 
-            UL([]),     'O1',           ['O1'],
+            UL([]),     'O1',           ['O', '1'],
             UL([]),     ['O2'],         ['O2'],
             UL([]),     UL(['O3']),     UL(['O3']),
             UL([]),     '',             UL([]),
@@ -920,7 +920,7 @@ class EnvironmentTestCase(unittest.TestCase):
             [''],       [''],           ['', ''],
             [''],       UL(['']),       UL(['', '']),
 
-            UL(['']),   'Q1',           ['', 'Q1'],
+            UL(['']),   'Q1',           ['', 'Q', '1'],
             UL(['']),   ['Q2'],         ['', 'Q2'],
             UL(['']),   UL(['Q3']),     UL(['', 'Q3']),
             UL(['']),   '',             UL(['']),
@@ -1297,7 +1297,7 @@ class EnvironmentTestCase(unittest.TestCase):
             ['e7'],     [''],           ['', 'e7'],
             ['e8'],     UL(['']),       UL(['', 'e8']),
 
-            UL(['i1']), 'I1',           UL(['I1', 'i1']),
+            UL(['i1']), 'I1',           UL(['I', '1', 'i1']),
             UL(['i2']), ['I2'],         UL(['I2', 'i2']),
             UL(['i3']), UL(['I3']),     UL(['I3', 'i3']),
             UL(['i4']), '',             UL(['i4']),
@@ -1324,7 +1324,7 @@ class EnvironmentTestCase(unittest.TestCase):
             [],         [''],           [''],
             [],         UL(['']),       UL(['']),
 
-            UL([]),     'O1',           UL(['O1']),
+            UL([]),     'O1',           UL(['O', '1']),
             UL([]),     ['O2'],         UL(['O2']),
             UL([]),     UL(['O3']),     UL(['O3']),
             UL([]),     '',             UL([]),
@@ -1342,7 +1342,7 @@ class EnvironmentTestCase(unittest.TestCase):
             [''],       [''],           ['', ''],
             [''],       UL(['']),       UL(['', '']),
 
-            UL(['']),   'Q1',           UL(['Q1', '']),
+            UL(['']),   'Q1',           UL(['Q', '1', '']),
             UL(['']),   ['Q2'],         UL(['Q2', '']),
             UL(['']),   UL(['Q3']),     UL(['Q3', '']),
             UL(['']),   '',             UL(['']),