Fixed optimization of filters and misoptimizations with changed eval context

jinja2/nodes.py

@@ -94,16 +94,6 @@ def revert(self, old):
         self.__dict__.update(old)
 
 
-def get_eval_context(node, ctx):
-    if ctx is None:
-        if node.environment is None:
-            raise RuntimeError('if no eval context is passed, the '
-                               'node must have an attached '
-                               'environment.')
-        return EvalContext(node.environment)
-    return ctx
-
-
 class Node(with_metaclass(NodeType, object)):
     """Baseclass for all Jinja2 nodes.  There are a number of nodes available
     of different types.  There are four major types:
@@ -356,14 +346,10 @@ class Expr(Node):
     """Baseclass for all expressions."""
     abstract = True
 
-    def as_const(self, eval_ctx=None):
+    def as_const(self, eval_ctx):
         """Return the value of the expression as constant or raise
         :exc:`Impossible` if this was not possible.
 
-        An :class:`EvalContext` can be provided, if none is given
-        a default context is created which requires the nodes to have
-        an attached environment.
-
         .. versionchanged:: 2.4
            the `eval_ctx` parameter was added.
         """
@@ -380,8 +366,7 @@ class BinExpr(Expr):
     operator = None
     abstract = True
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         # intercepted operators cannot be folded at compile time
         if self.environment.sandboxed and \
            self.operator in self.environment.intercepted_binops:
@@ -399,8 +384,7 @@ class UnaryExpr(Expr):
     operator = None
     abstract = True
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         # intercepted operators cannot be folded at compile time
         if self.environment.sandboxed and \
            self.operator in self.environment.intercepted_unops:
@@ -440,7 +424,7 @@ class Const(Literal):
     """
     fields = ('value',)
 
-    def as_const(self, eval_ctx=None):
+    def as_const(self, eval_ctx):
         return self.value
 
     @classmethod
@@ -459,8 +443,7 @@ class TemplateData(Literal):
     """A constant template string."""
     fields = ('data',)
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         if eval_ctx.volatile:
             raise Impossible()
         if eval_ctx.autoescape:
@@ -475,8 +458,7 @@ class Tuple(Literal):
     """
     fields = ('items', 'ctx')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return tuple(x.as_const(eval_ctx) for x in self.items)
 
     def can_assign(self):
@@ -490,8 +472,7 @@ class List(Literal):
     """Any list literal such as ``[1, 2, 3]``"""
     fields = ('items',)
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return [x.as_const(eval_ctx) for x in self.items]
 
 
@@ -501,26 +482,23 @@ class Dict(Literal):
     """
     fields = ('items',)
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return dict(x.as_const(eval_ctx) for x in self.items)
 
 
 class Pair(Helper):
     """A key, value pair for dicts."""
     fields = ('key', 'value')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return self.key.as_const(eval_ctx), self.value.as_const(eval_ctx)
 
 
 class Keyword(Helper):
     """A key, value pair for keyword arguments where key is a string."""
     fields = ('key', 'value')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return self.key, self.value.as_const(eval_ctx)
 
 
@@ -530,8 +508,7 @@ class CondExpr(Expr):
     """
     fields = ('test', 'expr1', 'expr2')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         if self.test.as_const(eval_ctx):
             return self.expr1.as_const(eval_ctx)
 
@@ -551,9 +528,8 @@ class Filter(Expr):
     """
     fields = ('node', 'name', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
-        if eval_ctx.volatile or self.node is None:
+    def as_const(self, eval_ctx):
+        if self.node is None:
             raise Impossible()
         # we have to be careful here because we call filter_ below.
         # if this variable would be called filter, 2to3 would wrap the
@@ -563,9 +539,10 @@ def as_const(self, eval_ctx=None):
         filter_ = self.environment.filters.get(self.name)
         if filter_ is None or getattr(filter_, 'contextfilter', False):
             raise Impossible()
-        obj = self.node.as_const(eval_ctx)
-        args = [x.as_const(eval_ctx) for x in self.args]
+        args = [x.as_const(eval_ctx) for x in [self.node] + self.args]
         if getattr(filter_, 'evalcontextfilter', False):
+            if eval_ctx.volatile:
+                raise Impossible()
             args.insert(0, eval_ctx)
         elif getattr(filter_, 'environmentfilter', False):
             args.insert(0, self.environment)
@@ -581,7 +558,7 @@ def as_const(self, eval_ctx=None):
             except Exception:
                 raise Impossible()
         try:
-            return filter_(obj, *args, **kwargs)
+            return filter_(*args, **kwargs)
         except Exception:
             raise Impossible()
 
@@ -602,10 +579,7 @@ class Call(Expr):
     """
     fields = ('node', 'args', 'kwargs', 'dyn_args', 'dyn_kwargs')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
-        if eval_ctx.volatile:
-            raise Impossible()
+    def as_const(self, eval_ctx):
         obj = self.node.as_const(eval_ctx)
 
         # don't evaluate context functions
@@ -614,6 +588,8 @@ def as_const(self, eval_ctx=None):
             if getattr(obj, 'contextfunction', False):
                 raise Impossible()
             elif getattr(obj, 'evalcontextfunction', False):
+                if eval_ctx.volatile:
+                    raise Impossible()
                 args.insert(0, eval_ctx)
             elif getattr(obj, 'environmentfunction', False):
                 args.insert(0, self.environment)
@@ -639,8 +615,7 @@ class Getitem(Expr):
     """Get an attribute or item from an expression and prefer the item."""
     fields = ('node', 'arg', 'ctx')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         if self.ctx != 'load':
             raise Impossible()
         try:
@@ -659,11 +634,10 @@ class Getattr(Expr):
     """
     fields = ('node', 'attr', 'ctx')
 
-    def as_const(self, eval_ctx=None):
+    def as_const(self, eval_ctx):
         if self.ctx != 'load':
             raise Impossible()
         try:
-            eval_ctx = get_eval_context(self, eval_ctx)
             return self.environment.getattr(self.node.as_const(eval_ctx),
                                             self.attr)
         except Exception:
@@ -679,8 +653,7 @@ class Slice(Expr):
     """
     fields = ('start', 'stop', 'step')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         def const(obj):
             if obj is None:
                 return None
@@ -694,8 +667,7 @@ class Concat(Expr):
     """
     fields = ('nodes',)
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return ''.join(text_type(x.as_const(eval_ctx)) for x in self.nodes)
 
 
@@ -705,8 +677,7 @@ class Compare(Expr):
     """
     fields = ('expr', 'ops')
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         result = value = self.expr.as_const(eval_ctx)
         try:
             for op in self.ops:
@@ -769,17 +740,15 @@ class And(BinExpr):
     """Short circuited AND."""
     operator = 'and'
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return self.left.as_const(eval_ctx) and self.right.as_const(eval_ctx)
 
 
 class Or(BinExpr):
     """Short circuited OR."""
     operator = 'or'
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return self.left.as_const(eval_ctx) or self.right.as_const(eval_ctx)
 
 
@@ -845,8 +814,7 @@ class MarkSafe(Expr):
     """Mark the wrapped expression as safe (wrap it as `Markup`)."""
     fields = ('expr',)
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         return Markup(self.expr.as_const(eval_ctx))
 
 
@@ -858,8 +826,7 @@ class MarkSafeIfAutoescape(Expr):
     """
     fields = ('expr',)
 
-    def as_const(self, eval_ctx=None):
-        eval_ctx = get_eval_context(self, eval_ctx)
+    def as_const(self, eval_ctx):
         if eval_ctx.volatile:
             raise Impossible()
         expr = self.expr.as_const(eval_ctx)

jinja2/optimizer.py

@@ -31,6 +31,7 @@ class Optimizer(NodeTransformer):
 
     def __init__(self, environment):
         self.environment = environment
+        self.eval_ctx = nodes.EvalContext(environment)
 
     def visit_If(self, node):
         """Eliminate dead code."""
@@ -39,7 +40,7 @@ def visit_If(self, node):
         if node.find(nodes.Block) is not None:
             return self.generic_visit(node)
         try:
-            val = self.visit(node.test).as_const()
+            val = self.visit(node.test).as_const(self.eval_ctx)
         except nodes.Impossible:
             return self.generic_visit(node)
         if val:
@@ -51,11 +52,27 @@ def visit_If(self, node):
             result.extend(self.visit_list(node))
         return result
 
+    def visit_EvalContextModifier(self, node):
+        for keyword in node.options:
+            try:
+                value = keyword.value.as_const(self.eval_ctx)
+            except nodes.Impossible:
+                self.eval_ctx.volatile = True
+            else:
+                setattr(self.eval_ctx, keyword.key, value)
+        return self.generic_visit(node)
+
+    def visit_ScopedEvalContextModifier(self, node):
+        backup = self.eval_ctx.save()
+        node = self.visit_EvalContextModifier(node)
+        self.eval_ctx.revert(backup)
+        return node
+
     def fold(self, node):
         """Do constant folding."""
         node = self.generic_visit(node)
         try:
-            return nodes.Const.from_untrusted(node.as_const(),
+            return nodes.Const.from_untrusted(node.as_const(self.eval_ctx),
                                               lineno=node.lineno,
                                               environment=self.environment)
         except nodes.Impossible: