Fix filter and Array.at and set_at to correctly handle errors

distribution/lib/Standard/Base/0.2.32-SNAPSHOT/src/Data/Vector.enso

@@ -140,7 +140,7 @@ type Vector
          Get the last element of a vector.
 
              [1, 2, 3].at -1 == 3
-    at : Number -> Any ! Index_Out_Of_Bounds_Error
+    at : Integer -> Any ! Index_Out_Of_Bounds_Error
     at index =
         actual_index = if index < 0 then this.length + index else index
         if actual_index>=0 && actual_index<this.length then this.to_array.at actual_index else
@@ -153,7 +153,7 @@ type Vector
        indices and will panic with a raw Java exception on out-of-bounds access.
        Thus it should only be used when the access is guaranteed to be within
        bounds or with additional error handling.
-    unsafe_at : Number -> Any
+    unsafe_at : Integer -> Any
     unsafe_at index =
         this.to_array.at index
 
@@ -325,9 +325,14 @@ type Vector
     filter : (Any -> Boolean) -> Vector Any
     filter predicate =
         builder = here.new_builder
-        this.each elem->
-            if predicate elem then builder.append elem
-        builder.to_vector
+        acc = this.fold Nothing acc-> elem->
+            ## The accumulator is threaded through to preserve dataflow
+               dependencies which are cut by using the stateful builder. This to
+               ensure correct dataflow error propagation.
+            case acc of
+                _ -> if predicate elem then builder.append elem
+        case acc of
+            _ -> builder.to_vector
 
     ## Applies a function to each element of the vector, returning the vector of
        results.
@@ -526,7 +531,7 @@ type Vector
          Join the elements of the vector together as a string.
 
              ["foo", "bar", "baz"].join ", "
-    join : String -> Text
+    join : Text -> Text
     join separator =
         if this.length == 0 then "" else
             if this.length == 1 then this.unsafe_at 0 else

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/GetAtNode.java

@@ -1,8 +1,11 @@
 package org.enso.interpreter.node.expression.builtin.mutable;
 
 import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.Language;
 import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.runtime.builtin.Builtins;
 import org.enso.interpreter.runtime.data.Array;
+import org.enso.interpreter.runtime.error.PanicException;
 
 @BuiltinMethod(
     type = "Array",
@@ -11,6 +14,11 @@
 public class GetAtNode extends Node {
 
   Object execute(Array _this, long index) {
-    return _this.getItems()[(int) index];
+    try {
+      return _this.getItems()[(int) index];
+    } catch (IndexOutOfBoundsException exception) {
+      Builtins builtins = lookupContextReference(Language.class).get().getBuiltins();
+      throw new PanicException(builtins.error().makeInvalidArrayIndexError(_this, index), this);
+    }
   }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/mutable/SetAtNode.java

@@ -1,9 +1,12 @@
 package org.enso.interpreter.node.expression.builtin.mutable;
 
 import com.oracle.truffle.api.nodes.Node;
+import org.enso.interpreter.Language;
 import org.enso.interpreter.dsl.AcceptsError;
 import org.enso.interpreter.dsl.BuiltinMethod;
+import org.enso.interpreter.runtime.builtin.Builtins;
 import org.enso.interpreter.runtime.data.Array;
+import org.enso.interpreter.runtime.error.PanicException;
 
 @BuiltinMethod(
     type = "Array",
@@ -12,7 +15,12 @@
 public class SetAtNode extends Node {
 
   Object execute(Array _this, long index, @AcceptsError Object value) {
-    _this.getItems()[(int) index] = value;
-    return _this;
+    try {
+      _this.getItems()[(int) index] = value;
+      return _this;
+    } catch (IndexOutOfBoundsException exception) {
+      Builtins builtins = lookupContextReference(Language.class).get().getBuiltins();
+      throw new PanicException(builtins.error().makeInvalidArrayIndexError(_this, index), this);
+    }
   }
 }

engine/runtime/src/main/resources/Builtins.enso

@@ -874,6 +874,10 @@ type Array
        Arguments:
        - index: The index to get the element from.
 
+       ? Safety
+         If index < 0 or index >= this.length, then this operation will result
+         in an Invalid_Array_Index_Error exception.
+
        > Example
          Get the element at index 1.
 
@@ -892,8 +896,8 @@ type Array
        programming style in Enso.
 
        ? Safety
-         If index >= this.length, then this operation will result in an
-         Invalid_Array_Index_Error exception.
+         If index < 0 or index >= this.length, then this operation will result
+         in an Invalid_Array_Index_Error exception.
     set_at : Integer -> Any -> Array
     set_at index value = @Builtin_Method "Array.set_at"
 

test/Tests/src/Data/Array_Spec.enso

@@ -10,3 +10,19 @@ spec = Test.group "Arrays" <|
         as_vec = json.into (Vector.Vector Number)
         as_vec.should_equal <| Vector.fill 100 0
 
+    Test.specify "should allow accessing elements"
+        arr = [1, 2, 3] . to_array
+        arr.at 0 . should_equal 1
+        arr.at 2 . should_equal 3
+
+    Test.specify "should allow setting elements"
+        arr = [1, 2, 3] . to_array
+        arr.set_at 1 10
+        arr.at 1 . should_equal 10
+        Vector.from_array arr . should_equal [1, 10, 3]
+
+    Test.specify "should panic on out of bounds access"
+        arr = [1, 2, 3] . to_array
+        Test.expect_panic_with (arr.at -1) Invalid_Array_Index_Error
+        Test.expect_panic_with (arr.at 3) Invalid_Array_Index_Error
+        Test.expect_panic_with (arr.at 3 100) Invalid_Array_Index_Error

test/Tests/src/Data/Vector_Spec.enso

@@ -90,6 +90,7 @@ spec = Test.group "Vectors" <|
         vec.filter (ix -> ix > 3) . should_equal [4, 5]
         vec.filter (ix -> ix == 1) . should_equal [1]
         vec.filter (ix -> ix < 0) . should_equal []
+        vec.filter (ix -> if ix == 2 then Error.throw <| My_Error "foo" else True) . should_fail_with My_Error
 
     Test.specify "should allow mapping an operation, returning a new vector" <|
         vec = [1, 2, 3, 4]