LoxiGen: workaround a Tenjin bug
Because the variable context is shared between nested includes (aka dynamic
scope), and because Tenjin explicitly deletes variables from the context after
the include is finished, we have a problem where the outer template's context
variables are deleted by the inner template.
Fix it by subclassing tenjin.Engine and rewriting include. We can't delegate to
the original include because it uses stack frame magic.
diff --git a/loxi_utils/loxi_utils.py b/loxi_utils/loxi_utils.py
index cc3e635..5508c94 100644
--- a/loxi_utils/loxi_utils.py
+++ b/loxi_utils/loxi_utils.py
@@ -33,6 +33,7 @@
These may need to be sorted out into language specific functions
"""
+import sys
import of_g
import tenjin
@@ -502,7 +503,7 @@
"""
pp = [ tenjin.PrefixedLinePreprocessor() ] # support "::" syntax
template_globals = { "to_str": str, "escape": str } # disable HTML escaping
- engine = tenjin.Engine(path=path, pp=pp)
+ engine = TemplateEngine(path=path, pp=pp)
out.write(engine.render(name, context, template_globals))
def render_static(out, name, path):
@@ -518,3 +519,18 @@
raise ValueError("template %s not found" % name)
with open(template_filename) as infile:
out.write(infile.read())
+
+class TemplateEngine(tenjin.Engine):
+ def include(self, template_name, **kwargs):
+ """
+ Tenjin has an issue with nested includes that use the same local variable
+ names, because it uses the same context dict for each level of nesting.
+ The fix is to copy the context.
+ """
+ frame = sys._getframe(1)
+ locals = frame.f_locals
+ globals = frame.f_globals
+ context = locals["_context"].copy()
+ context.update(kwargs)
+ template = self.get_template(template_name, context, globals)
+ return template.render(context, globals, _buf=locals["_buf"])