Different error for call stack overflow

Summary:
Before this diff "Too many recursion levels" error was used for both:
* call stack overflow
* equality/comparison evaluation stack overflow

Change call stack overflow error to "Starlark call stack overflow" to make error easier to investigate.

Reviewed By: bobyangyf

Differential Revision: D38705604

fbshipit-source-id: d9cde9799ba1f51eb9c41011d62f18e5a083acb3

Author: stepancheg

starlark/src/eval/runtime/call_stack.rs

@@ -37,7 +37,6 @@ use crate::codemap::FileSpan;
 use crate::codemap::Span;
 use crate::errors::Frame;
 use crate::eval::runtime::inlined_frame::InlinedFrames;
-use crate::values::error::ControlError;
 use crate::values::FrozenRef;
 use crate::values::Trace;
 use crate::values::Tracer;
@@ -157,6 +156,8 @@ impl Debug for CheapFrame<'_> {
 enum CallStackError {
     #[error("Requested {0}-th top frame, but stack size is {1} (internal error)")]
     StackIsTooShallowForNthTopFrame(usize, usize),
+    #[error("Starlark call stack overflow")]
+    Overflow,
 }
 
 /// Starlark call stack.
@@ -209,7 +210,7 @@ impl<'v> CheapCallStack<'v> {
         span: Option<FrozenRef<'static, FrozenFileSpan>>,
     ) -> anyhow::Result<()> {
         if unlikely(self.count >= MAX_CALLSTACK_RECURSION) {
-            return Err(ControlError::TooManyRecursionLevel.into());
+            return Err(CallStackError::Overflow.into());
         }
         self.stack[self.count] = CheapFrame { function, span };
         self.count += 1;

starlark/src/tests/call.rs

@@ -62,8 +62,8 @@ def rec6(): rec2()
     assert::is_true(&f("(f5(1, b=2) == {'b': 2})"));
     assert::is_true(&f("(f6(1, 2, 3) == (1, 2, 3))"));
     // Recursion limit
-    assert::fail(&f("rec1()"), "recursion");
-    assert::fail(&f("rec2()"), "recursion");
+    assert::fail(&f("rec1()"), "Starlark call stack overflow");
+    assert::fail(&f("rec2()"), "Starlark call stack overflow");
     // multiple argument with the same name should not be allowed
     assert::fail("def f(a, a=2): pass", "duplicated parameter");
     // Invalid order of parameter