This is a small tweak to the logic added in cl/1511 to detect explicit
throws when printing stack traces. Now when deciding whether to print
"caused by explicit throw", it checks not only that the error is a
ThrowError and that we are in a throw, but also that the ThrowError was
thrown by *this* throw, and not by another while in the process of
evaluating this throw's operand.
It turns this:
```
let
set = {
inner = throw "nested throw";
};
in
throw set.inner
error:
… caused by explicit throw
at /pwd/in.nix:6:1:
5| in
6| throw set.inner
| ^
7|
… while evaluating the attribute 'inner'
at /pwd/in.nix:3:5:
2| set = {
3| inner = throw "nested throw";
| ^
4| };
… caused by explicit throw
at /pwd/in.nix:3:13:
2| set = {
3| inner = throw "nested throw";
| ^
4| };
error: nested throw
```
into this:
```
error:
… while calling the 'throw' builtin
at /pwd/in.nix:6:1:
5| in
6| throw set.inner
| ^
7|
… while evaluating the attribute 'inner'
at /pwd/in.nix:3:5:
2| set = {
3| inner = throw "nested throw";
| ^
4| };
… caused by explicit throw
at /pwd/in.nix:3:13:
2| set = {
3| inner = throw "nested throw";
| ^
4| };
error: nested throw
```
Notice the difference in the top context frame. Before it incorrectly
attributed the throw error to the both throws instead of just the one
that actually threw.
Change-Id: If3b0b8311f1ae2ff1471e260fe59d9166a6a6964
All changes are uniform and done with the same script, so checking only
some should suffice. For that reason, any tests involving multiple files
or custom CLI flags are not included in this commit.
Change-Id: Ib2d0e08937b56e241d99771a58aad34ed3ad308a
skye