From: Roger Pack <rogerdpack2@...>
Date: 2011-05-26T12:22:29+09:00
Subject: [ruby-core:36477] Re: Error reporting, backtraces and the debugger

> Nobuyoshi Nakada offered a patch that turns each backtrace entry into a
> Struct with to_str and inspect that return the existing (textual) format.
> The patch uses SCRIPT_LINES to return the source code text, if that has been
> populated.

Oh yeah I remember that.  I would be happy if something like it were accepted :)

>
> Roger also asked that method parameters should also be included in each
> entry.

This part is a bit harder, but would be ideal.


> (3) Adding the method-call binding to each exception entry (like rbx'
> MethodContext)

This is an interesting idea, though possibly a bit tricky.
You might be able to fake something like this today using ruby-debug
(override Exception.new and have it save an array of bindings?)

> (4) Providing a debugger hook that can be called when an exception object is
> *about* to be thrown, but before it actually is thrown. This way it's easier
> to discover the reason an exception is being thrown, because the call stack
> which led to it still exists.

Does catch Exception do this?

> (6) Providing a debugger capability to step "into" a method which is being
> passed a block. This is between "step over" and "step in" because it doesn't
> step into the method, but will stop on the first line of the passed block
> (if the method yields, otherwise it's like "step over"). This would be
> especially useful for nested trace blocks (trace "foo" { ... }) where you
> always want to step into the block and never into the trace method itself.

That would be nice.  Maybe there is already such an option you can
ping the ruby-debug google group.

-roger-