Add array and object comprehensions to stack trace frames (#638)

## Summary
- Array comprehensions (`Comp`) and object comprehensions
(`ObjBody.ObjComp`) now appear in stack traces as `[array
comprehension]` and `[object comprehension]`, giving better context when
errors originate inside comprehension bodies.
- Adds `exprErrorString` overrides and includes both types in the
`isApplyOrBuiltin` frame filter.

## Test plan
- [x] JVM tests pass (140/140)
- [x] 12 golden files updated with new comprehension frames
- [x] 3 EvaluatorTests assertions updated

Author: stephenamar-db

sjsonnet/src/sjsonnet/Error.scala

@@ -54,7 +54,8 @@ class Error(msg: String, val stack: List[Error.Frame] = Nil, underlying: Option[
   private def isApplyOrBuiltin(expr: Expr): Boolean = expr match {
     case _: Expr.Apply | _: Expr.Apply0 | _: Expr.Apply1 | _: Expr.Apply2 | _: Expr.Apply3 |
         _: Expr.ApplyBuiltin | _: Expr.ApplyBuiltin0 | _: Expr.ApplyBuiltin1 |
-        _: Expr.ApplyBuiltin2 | _: Expr.ApplyBuiltin3 | _: Expr.ApplyBuiltin4 =>
+        _: Expr.ApplyBuiltin2 | _: Expr.ApplyBuiltin3 | _: Expr.ApplyBuiltin4 | _: Expr.Comp |
+        _: Expr.ObjBody.ObjComp =>
       true
     case _ => false
   }

sjsonnet/src/sjsonnet/Expr.scala

@@ -343,6 +343,7 @@ object Expr {
   final case class Comp(pos: Position, value: Expr, first: ForSpec, rest: Array[CompSpec])
       extends Expr {
     final override private[sjsonnet] def tag = ExprTags.Comp
+    override def exprErrorString: String = "array comprehension"
   }
   final case class ObjExtend(pos: Position, base: Expr, ext: ObjBody) extends Expr {
     final override private[sjsonnet] def tag = ExprTags.ObjExtend
@@ -371,6 +372,7 @@ object Expr {
         rest: List[CompSpec])
         extends ObjBody {
       final override private[sjsonnet] def tag = ExprTags.`ObjBody.ObjComp`
+      override def exprErrorString: String = "object comprehension"
       override def toString: String =
         s"ObjComp($pos, ${arrStr(preLocals)}, $key, $value, ${arrStr(postLocals)}, $first, $rest)"
     }

sjsonnet/test/resources/go_test_suite/array_comp_try_iterate_over_empty_string.jsonnet.golden

@@ -1,3 +1,4 @@
 sjsonnet.Error: In comprehension, can only iterate over array, not string
+    at [array comprehension].(array_comp_try_iterate_over_empty_string.jsonnet:1:4)
     at [<root>].(array_comp_try_iterate_over_empty_string.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/array_comp_try_iterate_over_obj.jsonnet.golden

@@ -1,3 +1,4 @@
 sjsonnet.Error: In comprehension, can only iterate over array, not object
+    at [array comprehension].(array_comp_try_iterate_over_obj.jsonnet:1:4)
     at [<root>].(array_comp_try_iterate_over_obj.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/array_comp_try_iterate_over_string.jsonnet.golden

@@ -1,3 +1,4 @@
 sjsonnet.Error: In comprehension, can only iterate over array, not string
+    at [array comprehension].(array_comp_try_iterate_over_string.jsonnet:1:4)
     at [<root>].(array_comp_try_iterate_over_string.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/arrcomp_if6.jsonnet.golden

@@ -1,3 +1,4 @@
 sjsonnet.Error: x
+    at [array comprehension].(arrcomp_if6.jsonnet:1:20)
     at [<root>].(arrcomp_if6.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/arrcomp_if7.jsonnet.golden

@@ -1,3 +1,4 @@
 sjsonnet.Error: Condition must be boolean, got number
+    at [array comprehension].(arrcomp_if7.jsonnet:1:23)
     at [<root>].(arrcomp_if7.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/object_comp_duplicate.jsonnet.golden

@@ -1,3 +1,3 @@
-sjsonnet.Error: Duplicate key x in evaluated object comprehension.
+sjsonnet.Error: [object comprehension] Duplicate key x in evaluated object comprehension.
     at [<root>].(object_comp_duplicate.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/object_comp_err_index.jsonnet.golden

@@ -1,3 +1,4 @@
 sjsonnet.Error: xxx
+    at [object comprehension].(object_comp_err_index.jsonnet:1:4)
     at [<root>].(object_comp_err_index.jsonnet:1:1)
 

sjsonnet/test/resources/go_test_suite/object_comp_int_index.jsonnet.golden

@@ -1,3 +1,3 @@
-sjsonnet.Error: Field name must be string or null, not number
+sjsonnet.Error: [object comprehension] Field name must be string or null, not number
     at [<root>].(object_comp_int_index.jsonnet:1:1)