On Monday, 30 December 2019 at 18:18:49 UTC, uranuz wrote:
I have created library/ framework to handle JSON-RPC requests
using D methods. I use some *template magic* to translate
JSON-RPC parameters and return values from/ and to JSON. And I
have encountered funny bug that at first was hard to find. My
programme just segfaulted when call to this method occured:
void getCompiledTemplate(HTTPContext ctx)
{
import std.exception: enforce;
enforce(ctx, `ctx is null`);
enforce(ctx.request, `ctx.request is null`);
enforce(ctx.request.form, `ctx.request is null`);
enforce(ivyEngine !is null, `ivyEngine is null`);
string moduleName = ctx.request.form[`moduleName`];
auto mod = ivyEngine.getByModuleName(moduleName);
return ctx.response.write(mod.toStdJSON().toString());
}
So as you see I have added a lot of enforce to test if all
variables are not null. But nothing was null and the reason of
segfault were unclear.
Today I just went home. Opened a bottle of beer. And have
noticed that function is marked as returning `void`, but in
fact it doesn't. When I fixed this segfault have gone. But why
this even compiled?! Interesting...
We also have a piece of code, see here
https://github.com/huntlabs/hunt-examples/blob/master/website-basic/source/app/controller/IndexController.d#L133.
It's a wrong function declaration.
There is no error message when compiling it. However, the
showString() can't be called via the browser, because the router
mapping fails.
What happened for this is that the IndexController is not used
directly by others. It's used in `mixin MakeController;`, see
https://github.com/huntlabs/hunt-framework/blob/master/source/hunt/framework/application/Controller.d#L153.
So the conclusion is the mixin needs to do more works to check
the validation in mixined code.
