pop top frame from stack if we throw evaluating it (#111)

* pop top frame from stack if we error evaluating it

* add breakpoint test

Author: KristofferC

src/interpret.jl

@@ -212,7 +212,12 @@ function evaluate_call!(stack, frame::JuliaStackFrame, call_expr::Expr, pc; exec
         push!(stack, newframe)
         return BreakpointRef(newframe.code, newframe.pc[])
     end
-    ret = exec!(stack, newframe)
+    ret = try
+        exec!(stack, newframe)
+    catch e
+        pop!(stack)
+        rethrow(e)
+    end
     isa(ret, BreakpointRef) && return ret
     pop!(stack)
     push!(junk, newframe)  # rather than going through GC, just re-use it

test/breakpoints.jl

@@ -118,6 +118,7 @@ end
         frame = JuliaInterpreter.enter_call(f_exc_outer);
         v = JuliaInterpreter.finish_and_return!(stack, frame)
         @test v isa ErrorException
+        @test isempty(stack)
     finally
         JuliaInterpreter.break_on_error[] = false
     end