feat(parser,execution-engine): allow :error: in fail (#696)

The `(fail :error:)` was previously rejected by parser.  Now it is
executed, but is of limited use.

air/src/execution_step/instructions/fail.rs

@@ -46,6 +46,7 @@ impl<'i> super::ExecutableInstruction<'i> for Fail<'i> {
             Fail::CanonStreamWithLambda(canon_stream) => fail_with_canon_stream(canon_stream, exec_ctx),
             // bubble last error up
             Fail::LastError => fail_with_last_error(exec_ctx),
+            Fail::Error => fail_with_error(exec_ctx),
         }
     }
 }
@@ -117,6 +118,18 @@ fn fail_with_last_error(exec_ctx: &mut ExecutionCtx<'_>) -> ExecutionResult<()>
     fail_with_error_object(exec_ctx, error, tetraplet, provenance.clone())
 }
 
+fn fail_with_error(exec_ctx: &mut ExecutionCtx<'_>) -> ExecutionResult<()> {
+    use crate::execution_step::InstructionError;
+
+    let InstructionError {
+        error,
+        tetraplet,
+        provenance,
+    } = exec_ctx.error_descriptor.error();
+
+    fail_with_error_object(exec_ctx, error.clone(), tetraplet.clone(), provenance.clone())
+}
+
 fn fail_with_error_object(
     exec_ctx: &mut ExecutionCtx<'_>,
     error: Rc<JValue>,

air/tests/test_module/instructions/fail.rs

@@ -44,6 +44,33 @@ fn fail_with_last_error() {
     assert!(check_error(&result, expected_error));
 }
 
+#[test]
+fn fail_with_error() {
+    let local_peer_id = "local_peer_id";
+    let fallible_service_id = "service_id_1";
+    let mut vm = create_avm(fallible_call_service(fallible_service_id), local_peer_id);
+
+    let script = format!(
+        r#"
+            (xor
+                (call "{local_peer_id}" ("service_id_1" "local_fn_name") [] result_1)
+                (fail :error:)
+            )"#
+    );
+
+    let result = call_vm!(vm, <_>::default(), script, "", "");
+
+    let expected_error = CatchableError::UserError {
+        error: rc!(json!({
+            "error_code": 10000i64,
+            "instruction": r#"call "local_peer_id" ("service_id_1" "local_fn_name") [] result_1"#,
+            "message": r#"Local service error, ret_code is 1, error message is '"failed result from fallible_call_service"'"#,
+            "peer_id": "local_peer_id",
+        })),
+    };
+    assert!(check_error(&result, expected_error));
+}
+
 #[test]
 fn fail_with_literals() {
     let local_peer_id = "local_peer_id";
@@ -97,6 +124,34 @@ fn fail_with_last_error_tetraplets() {
     );
 }
 
+#[test]
+fn fail_with_error_tetraplets() {
+    let local_peer_id = "local_peer_id";
+    let fallible_service_id = "service_id_1";
+    let (host_closure, tetraplet_anchor) = tetraplet_host_function(fallible_call_service(fallible_service_id));
+    let mut vm = create_avm(host_closure, local_peer_id);
+
+    let local_fn_name = "local_fn_name";
+    let script = format!(
+        r#"
+        (xor
+            (xor
+                (call "{local_peer_id}" ("{fallible_service_id}" "{local_fn_name}") [] result_1)
+                (fail :error:)
+            )
+            (call "{local_peer_id}" ("" "") [%last_error%])
+        )
+          "#
+    );
+
+    let test_params = TestRunParameters::from_init_peer_id(local_peer_id);
+    let _ = checked_call_vm!(vm, test_params, script, "", "");
+    assert_eq!(
+        tetraplet_anchor.borrow()[0][0],
+        SecurityTetraplet::new(local_peer_id, fallible_service_id, local_fn_name, "")
+    );
+}
+
 #[test]
 fn fail_with_literals_tetraplets() {
     let local_peer_id = "local_peer_id";

crates/air-lib/air-parser/src/ast/instructions.rs

@@ -137,6 +137,7 @@ pub enum Fail<'i> {
     },
     CanonStreamWithLambda(CanonStreamWithLambda<'i>),
     LastError,
+    Error,
 }
 
 /// (fold scalar_iterable iterator instruction)

crates/air-lib/air-parser/src/ast/instructions/traits.rs

@@ -111,6 +111,7 @@ impl fmt::Display for Fail<'_> {
                 write!(f, "fail {stream}")
             }
             Fail::LastError => write!(f, "fail %last_error%"),
+            Fail::Error => write!(f, "fail :error:"),
         }
     }
 }

crates/air-lib/air-parser/src/parser/air.lalrpop

@@ -190,6 +190,9 @@ FailBody: Fail<'input> = {
     <canon_stream:CanonStreamWithLambda> => Fail::CanonStreamWithLambda(CanonStreamWithLambda::new(canon_stream.0, canon_stream.1, canon_stream.2)),
     <left: @L> <l:LastError> <right: @R> => {
         Fail::LastError
+    },
+    <left: @L> <l:Error> <right: @R> => {
+        Fail::Error
     }
 }
 

crates/beautifier/src/tests/beautifier.rs

@@ -381,3 +381,10 @@ fn deeply_nested() {
     let expected = include_str!("deeply_nested_expected.txt");
     assert_eq!(output, expected);
 }
+
+#[test]
+fn fail_error() {
+    let script = r#"(fail :error:)"#;
+    let output = beautify_to_string(script).unwrap();
+    assert_eq!(output, "fail :error:\n");
+}