Implement fail with scalars (#205)

air/src/execution_step/air/ap/apply_to_arguments.rs

@@ -27,7 +27,7 @@ pub(super) fn apply_to_arg(
     use ast::ApArgument::*;
 
     let result = match argument {
-        InitPeerId => apply_const(exec_ctx.init_peer_id.clone(), exec_ctx, trace_ctx),
+        InitPeerId => apply_const(exec_ctx.init_peer_id.as_str(), exec_ctx, trace_ctx),
         LastError(error_accessor) => apply_last_error(error_accessor, exec_ctx, trace_ctx)?,
         Literal(value) => apply_const(*value, exec_ctx, trace_ctx),
         Number(value) => apply_const(value, exec_ctx, trace_ctx),
@@ -41,7 +41,7 @@ pub(super) fn apply_to_arg(
 
 fn apply_const(value: impl Into<JValue>, exec_ctx: &ExecutionCtx<'_>, trace_ctx: &TraceHandler) -> ValueAggregate {
     let value = Rc::new(value.into());
-    let tetraplet = SecurityTetraplet::literal_tetraplet(exec_ctx.init_peer_id.clone());
+    let tetraplet = SecurityTetraplet::literal_tetraplet(exec_ctx.init_peer_id.as_ref());
     let tetraplet = Rc::new(RefCell::new(tetraplet));
 
     ValueAggregate::new(value, tetraplet, trace_ctx.trace_pos())

air/src/execution_step/air/call.rs

@@ -73,10 +73,10 @@ fn set_last_error<'i>(
         current_peer_id
     );
 
-    let _ = exec_ctx.last_error_descriptor.try_to_set_from_ingredients(
+    let _ = exec_ctx.last_error_descriptor.try_to_set_from_error(
         catchable_error.as_ref(),
-        call.to_string(),
+        &call.to_string(),
-        current_peer_id,
+        &current_peer_id,
         tetraplet,
     );
     ExecutionError::Catchable(catchable_error)

air/src/execution_step/air/call/triplet.rs

@@ -48,7 +48,7 @@ fn resolve_to_string<'i>(value: &ast::CallInstrValue<'i>, ctx: &ExecutionCtx<'i>
     use ast::CallInstrValue::*;
 
     let resolved = match value {
-        InitPeerId => ctx.init_peer_id.clone(),
+        InitPeerId => ctx.init_peer_id.to_string(),
         Literal(value) => value.to_string(),
         Variable(variable) => {
             let (resolved, _) = resolve_ast_variable_wl(variable, ctx)?;

air/src/execution_step/air/compare_matchable/comparator.rs

@@ -80,7 +80,7 @@ fn compare_matchable<'ctx>(
     match matchable {
         InitPeerId => {
             let init_peer_id = exec_ctx.init_peer_id.clone();
-            let jvalue = init_peer_id.into();
+            let jvalue = init_peer_id.as_str().into();
             Ok(comparator(Cow::Owned(jvalue)))
         }
         LastError(error_accessor) => {

air/src/execution_step/air/fail.rs

@@ -17,6 +17,8 @@
 use super::ExecutionCtx;
 use super::ExecutionResult;
 use super::TraceHandler;
+use crate::execution_step::execution_context::check_error_object;
+use crate::execution_step::resolver::resolve_ast_scalar_wl;
 use crate::execution_step::CatchableError;
 use crate::execution_step::LastError;
 use crate::execution_step::RSecurityTetraplet;
@@ -24,6 +26,7 @@ use crate::log_instruction;
 use crate::ExecutionError;
 use crate::JValue;
 
+use air_parser::ast;
 use air_parser::ast::Fail;
 use polyplets::SecurityTetraplet;
 
@@ -35,6 +38,7 @@ impl<'i> super::ExecutableInstruction<'i> for Fail<'i> {
         log_instruction!(fail, exec_ctx, trace_ctx);
 
         match self {
+            Fail::Scalar(scalar) => fail_with_scalar(scalar, exec_ctx),
             &Fail::Literal {
                 ret_code,
                 error_message,
@@ -45,25 +49,32 @@ impl<'i> super::ExecutableInstruction<'i> for Fail<'i> {
     }
 }
 
+fn fail_with_scalar<'i>(scalar: &ast::ScalarWithLambda<'i>, exec_ctx: &mut ExecutionCtx<'i>) -> ExecutionResult<()> {
+    let (value, mut tetraplet) = resolve_ast_scalar_wl(scalar, exec_ctx)?;
+    // tetraplets always have one element here and it'll be refactored after boxed value
+    let tetraplet = tetraplet.remove(0);
+    check_error_object(&value).map_err(CatchableError::InvalidLastErrorObjectError)?;
+
+    fail_with_error_object(exec_ctx, Rc::new(value), Some(tetraplet))
+}
+
 fn fail_with_literals<'i>(
-    ret_code: i64,
+    error_code: i64,
     error_message: &str,
     fail: &Fail<'_>,
     exec_ctx: &mut ExecutionCtx<'i>,
 ) -> ExecutionResult<()> {
-    // TODO: decouple error object creation into a separate function
+    let error_object = crate::execution_step::execution_context::error_from_raw_fields(
-    let error_object = serde_json::json!({
+        error_code,
-        "error_code": ret_code,
+        error_message,
-        "message": error_message,
+        &fail.to_string(),
-        "instruction": fail.to_string(),
+        exec_ctx.init_peer_id.as_ref(),
-    });
+    );
-    let error_object = Rc::new(error_object);
 
-    // TODO: wrap exec.init_peer_id in Rc
+    let literal_tetraplet = SecurityTetraplet::literal_tetraplet(exec_ctx.init_peer_id.as_ref());
-    let literal_tetraplet = SecurityTetraplet::literal_tetraplet(exec_ctx.init_peer_id.clone());
     let literal_tetraplet = Rc::new(RefCell::new(literal_tetraplet));
 
-    fail_with_error_object(exec_ctx, error_object, Some(literal_tetraplet))
+    fail_with_error_object(exec_ctx, Rc::new(error_object), Some(literal_tetraplet))
 }
 
 fn fail_with_last_error(exec_ctx: &mut ExecutionCtx<'_>) -> ExecutionResult<()> {

air/src/execution_step/air/mod.rs

@@ -48,10 +48,11 @@ macro_rules! execute {
     ($self:expr, $instr:expr, $exec_ctx:ident, $trace_ctx:ident) => {{
         match $instr.execute($exec_ctx, $trace_ctx) {
             Err(e) => {
-                $exec_ctx.last_error_descriptor.try_to_set_from_ingredients(
+                $exec_ctx.last_error_descriptor.try_to_set_from_error(
                     &e,
-                    $instr.to_string(),
+                    // TODO: avoid excess copying here
-                    $exec_ctx.current_peer_id.to_string(),
+                    &$instr.to_string(),
+                    $exec_ctx.current_peer_id.as_ref(),
                     None,
                 );
                 Err(e)

air/src/execution_step/air/par.rs

@@ -38,10 +38,10 @@ impl<'i> ExecutableInstruction<'i> for Par<'i> {
         trace_to_exec_err!(trace_ctx.meet_par_start(), self)?;
 
         // execute a left subtree of par
-        let left_result = execute_subtree(&self, exec_ctx, trace_ctx, &mut completeness_updater, SubtreeType::Left)?;
+        let left_result = execute_subtree(self, exec_ctx, trace_ctx, &mut completeness_updater, SubtreeType::Left)?;
 
         // execute a right subtree of par
-        let right_result = execute_subtree(&self, exec_ctx, trace_ctx, &mut completeness_updater, SubtreeType::Right)?;
+        let right_result = execute_subtree(self, exec_ctx, trace_ctx, &mut completeness_updater, SubtreeType::Right)?;
 
         completeness_updater.set_completeness(exec_ctx);
         prepare_par_result(left_result, right_result, exec_ctx)

air/src/execution_step/errors/catchable_errors.rs

@@ -17,6 +17,7 @@
 use super::Joinable;
 use super::LastErrorAffectable;
 use super::Stream;
+use crate::execution_step::execution_context::LastErrorObjectError;
 use crate::execution_step::lambda_applier::LambdaError;
 use crate::JValue;
 use crate::ToErrorCode;
@@ -77,6 +78,10 @@ pub enum CatchableError {
     /// Errors occurred while insertion of a value inside stream that doesn't have corresponding generation.
     #[error("stream {0:?} doesn't have generation with number {1}, probably a supplied to the interpreter data is corrupted")]
     StreamDontHaveSuchGeneration(Stream, usize),
+
+    /// This error type is produced by a fail instruction that tries to throw a scalar that have inappropriate type.
+    #[error(transparent)]
+    InvalidLastErrorObjectError(#[from] LastErrorObjectError),
 }
 
 impl From<LambdaError> for Rc<CatchableError> {

air/src/execution_step/execution_context/context.rs

@@ -40,7 +40,7 @@ pub(crate) struct ExecutionCtx<'i> {
     pub(crate) current_peer_id: Rc<String>,
 
     /// PeerId of a peer send this AIR script.
-    pub(crate) init_peer_id: String,
+    pub(crate) init_peer_id: Rc<String>,
 
     /// Last error produced by local service.
     /// None means that there weren't any error.
@@ -78,7 +78,7 @@ impl<'i> ExecutionCtx<'i> {
 
         Self {
             current_peer_id,
-            init_peer_id,
+            init_peer_id: Rc::new(init_peer_id),
             subtree_complete: true,
             last_call_request_id,
             call_results,

air/src/execution_step/execution_context/last_error/errors.rs

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2021 Fluence Labs Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use crate::JValue;
+
+use thiserror::Error as ThisError;
+
+/// Describes errors related to converting a scalar into error object.
+#[derive(Debug, Clone, ThisError)]
+pub enum LastErrorObjectError {
+    #[error("scalar should have an object type to be converted into error object, but '{0}' doesn't have")]
+    ScalarMustBeObject(JValue),
+
+    #[error("scalar '{scalar}' must have field with name '{field_name}'")]
+    ScalarMustContainField { scalar: JValue, field_name: &'static str },
+
+    #[error("{field_name} of scalar '{scalar}' must have {expected_type} type")]
+    ScalarFieldIsWrongType {
+        scalar: JValue,
+        field_name: &'static str,
+        expected_type: &'static str,
+    },
+}

air/src/execution_step/execution_context/last_error/last_error_definition.rs

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2021 Fluence Labs Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use super::LastErrorObjectError;
+use crate::execution_step::RSecurityTetraplet;
+use crate::JValue;
+
+use serde::Deserialize;
+use serde::Serialize;
+
+use std::rc::Rc;
+
+pub const ERROR_CODE_FIELD_NAME: &str = "error_code";
+pub const MESSAGE_FIELD_NAME: &str = "message";
+pub const INSTRUCTION_FIELD_NAME: &str = "instruction";
+pub const PEER_ID_FIELD_NAME: &str = "peer_id";
+
+/// This struct is intended to track the last arisen error.
+/// LastError is essentially a scalar value with support of lambda expressions.
+/// The only differences from a scalar are
+///  - it's accessed by %last_error% literal
+///  - if it's unset before the usage, JValue::Null will be used without join behaviour
+///  - it's a global scalar, meaning that fold and new scopes doesn't apply for it
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct LastError {
+    /// Error object that represents the last occurred error.
+    pub error: Rc<JValue>,
+
+    /// Tetraplet that identify host where the error occurred.
+    pub tetraplet: Option<RSecurityTetraplet>,
+}
+
+pub(crate) fn error_from_raw_fields(error_code: i64, error_message: &str, instruction: &str, peer_id: &str) -> JValue {
+    serde_json::json!({
+        ERROR_CODE_FIELD_NAME: error_code,
+        MESSAGE_FIELD_NAME: error_message,
+        INSTRUCTION_FIELD_NAME: instruction,
+        PEER_ID_FIELD_NAME: peer_id,
+    })
+}
+
+/// Checks that a scalar is a value of an object types that contains at least two fields:
+///  - error_code
+///  - message
+pub(crate) fn check_error_object(scalar: &JValue) -> Result<(), LastErrorObjectError> {
+    let fields = match scalar {
+        JValue::Object(fields) => fields,
+        _ => return Err(LastErrorObjectError::ScalarMustBeObject(scalar.clone())),
+    };
+
+    let check_field = |field_name| {
+        fields
+            .get(field_name)
+            .ok_or_else(|| LastErrorObjectError::ScalarMustContainField {
+                scalar: scalar.clone(),
+                field_name,
+            })
+    };
+
+    let error_code = check_field(ERROR_CODE_FIELD_NAME)?;
+    ensure_jvalue_is_integer(scalar, error_code, ERROR_CODE_FIELD_NAME)?;
+
+    let message = check_field(MESSAGE_FIELD_NAME)?;
+    ensure_jvalue_is_string(scalar, message, MESSAGE_FIELD_NAME)?;
+
+    Ok(())
+}
+
+fn ensure_jvalue_is_integer(
+    scalar: &JValue,
+    value: &JValue,
+    field_name: &'static str,
+) -> Result<(), LastErrorObjectError> {
+    match value {
+        JValue::Number(number) if number.is_i64() || number.is_u64() => Ok(()),
+        _ => Err(LastErrorObjectError::ScalarFieldIsWrongType {
+            scalar: scalar.clone(),
+            field_name,
+            expected_type: "integer",
+        }),
+    }
+}
+
+fn ensure_jvalue_is_string(
+    scalar: &JValue,
+    value: &JValue,
+    field_name: &'static str,
+) -> Result<(), LastErrorObjectError> {
+    match value {
+        JValue::String(_) => Ok(()),
+        _ => Err(LastErrorObjectError::ScalarFieldIsWrongType {
+            scalar: scalar.clone(),
+            field_name,
+            expected_type: "string",
+        }),
+    }
+}

air/src/execution_step/execution_context/last_error/last_error_descriptor.rs

@@ -14,31 +14,15 @@
  * limitations under the License.
  */
 
+use super::last_error_definition::error_from_raw_fields;
+use super::LastError;
 use crate::execution_step::LastErrorAffectable;
 use crate::execution_step::RSecurityTetraplet;
 use crate::JValue;
 use crate::ToErrorCode;
 
-use serde::Deserialize;
-use serde::Serialize;
-
 use std::rc::Rc;
 
-/// This struct is intended to track the last arisen error.
-/// LastError is essentially a scalar value with support of lambda expressions.
-/// The only differences from a scalar are
-///  - it's accessed by %last_error% literal
-///  - if it's unset before the usage, JValue::Null will be used without join behaviour
-///  - it's a global scalar, meaning that fold and new scopes doesn't apply for it
-#[derive(Debug, Clone, Serialize, Deserialize)]
-pub struct LastError {
-    /// Error object that represents the last occurred error.
-    pub error: Rc<JValue>,
-
-    /// Tetraplet that identify host where the error occurred.
-    pub tetraplet: Option<RSecurityTetraplet>,
-}
-
 pub(crate) struct LastErrorDescriptor {
     last_error: LastError,
 
@@ -49,11 +33,11 @@ pub(crate) struct LastErrorDescriptor {
 }
 
 impl<'s> LastErrorDescriptor {
-    pub(crate) fn try_to_set_from_ingredients(
+    pub(crate) fn try_to_set_from_error(
         &mut self,
-        error: &(impl ToString + LastErrorAffectable + ToErrorCode),
+        error: &(impl LastErrorAffectable + ToErrorCode + ToString),
-        instruction: impl Into<String>,
+        instruction: &str,
-        peer_id: impl Into<String>,
+        peer_id: &str,
         tetraplet: Option<RSecurityTetraplet>,
     ) -> bool {
         // this check is optimization to prevent creation of an error object in case if error
@@ -61,13 +45,25 @@ impl<'s> LastErrorDescriptor {
         if !self.error_can_be_set || !error.affects_last_error() {
             return false;
         }
-        let error_object = serde_json::json!({
-            "error_code": error.to_error_code(),
-            "message": error.to_string(),
-            "instruction": instruction.into(),
-            "peer_id": peer_id.into(),
-        });
 
+        self.set_from_ingredients(
+            error.to_error_code(),
+            &error.to_string(),
+            instruction,
+            peer_id,
+            tetraplet,
+        )
+    }
+
+    pub(crate) fn set_from_ingredients(
+        &mut self,
+        error_code: i64,
+        error_message: &str,
+        instruction: &str,
+        peer_id: &str,
+        tetraplet: Option<RSecurityTetraplet>,
+    ) -> bool {
+        let error_object = error_from_raw_fields(error_code, error_message, instruction, peer_id);
         self.set_from_error_object(Rc::new(error_object), tetraplet);
         true
     }

air/src/execution_step/execution_context/last_error/mod.rs

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2020 Fluence Labs Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+mod errors;
+mod last_error_definition;
+mod last_error_descriptor;
+
+pub use errors::LastErrorObjectError;
+pub use last_error_definition::LastError;
+pub use last_error_definition::ERROR_CODE_FIELD_NAME;
+pub use last_error_definition::INSTRUCTION_FIELD_NAME;
+pub use last_error_definition::MESSAGE_FIELD_NAME;
+pub use last_error_definition::PEER_ID_FIELD_NAME;
+
+pub(crate) use last_error_definition::check_error_object;
+pub(crate) use last_error_definition::error_from_raw_fields;
+pub(crate) use last_error_descriptor::LastErrorDescriptor;

air/src/execution_step/execution_context/mod.rs

@@ -15,13 +15,12 @@
  */
 
 mod context;
-mod last_error_descriptor;
+mod last_error;
 mod scalar_variables;
 mod streams_variables;
 
-pub use last_error_descriptor::LastError;
+pub use last_error::*;
 
 pub(crate) use context::*;
-pub(crate) use last_error_descriptor::LastErrorDescriptor;
 pub(crate) use scalar_variables::*;
 pub(crate) use streams_variables::*;

air/src/execution_step/mod.rs

@@ -24,6 +24,7 @@ mod resolver;
 pub use errors::CatchableError;
 pub use errors::ExecutionError;
 pub use errors::UncatchableError;
+pub use execution_context::LastErrorObjectError;
 pub use lambda_applier::LambdaError;
 
 pub mod errors_prelude {

air/src/execution_step/resolver/resolve.rs

@@ -39,7 +39,7 @@ pub(crate) fn resolve_to_args<'i>(
     use ast::Value::*;
 
     match value {
-        InitPeerId => prepare_const(ctx.init_peer_id.clone(), ctx),
+        InitPeerId => prepare_const(ctx.init_peer_id.as_str(), ctx),
         LastError(error_accessor) => prepare_last_error(error_accessor, ctx),
         Literal(value) => prepare_const(value.to_string(), ctx),
         Boolean(value) => prepare_const(*value, ctx),
@@ -55,7 +55,7 @@ pub(crate) fn prepare_const(
     ctx: &ExecutionCtx<'_>,
 ) -> ExecutionResult<(JValue, SecurityTetraplets)> {
     let jvalue = arg.into();
-    let tetraplet = SecurityTetraplet::literal_tetraplet(ctx.init_peer_id.clone());
+    let tetraplet = SecurityTetraplet::literal_tetraplet(ctx.init_peer_id.as_ref());
     let tetraplet = Rc::new(RefCell::new(tetraplet));
 
     Ok((jvalue, vec![tetraplet]))
@@ -78,7 +78,7 @@ pub(crate) fn prepare_last_error<'i>(
     let tetraplets = match tetraplet {
         Some(tetraplet) => vec![tetraplet.clone()],
         None => {
-            let tetraplet = SecurityTetraplet::literal_tetraplet(&ctx.init_peer_id);
+            let tetraplet = SecurityTetraplet::literal_tetraplet(ctx.init_peer_id.as_ref());
             let tetraplet = Rc::new(RefCell::new(tetraplet));
             vec![tetraplet]
         }
@@ -128,6 +128,15 @@ pub(crate) fn resolve_ast_variable_wl<'ctx, 'i>(
     }
 }
 
+pub(crate) fn resolve_ast_scalar_wl<'ctx, 'i>(
+    ast_scalar: &ast::ScalarWithLambda<'_>,
+    exec_ctx: &'ctx ExecutionCtx<'i>,
+) -> ExecutionResult<(JValue, SecurityTetraplets)> {
+    // TODO: wrap lambda path with Rc to make this clone cheaper
+    let variable = ast::VariableWithLambda::Scalar(ast_scalar.clone());
+    resolve_ast_variable_wl(&variable, exec_ctx)
+}
+
 pub(crate) fn apply_lambda<'i>(
     variable: Variable<'_>,
     lambda: &LambdaAST<'i>,

air/src/lib.rs

@@ -38,6 +38,7 @@ pub use execution_step::execution_context::LastError;
 pub use execution_step::CatchableError;
 pub use execution_step::ExecutionError;
 pub use execution_step::LambdaError;
+pub use execution_step::LastErrorObjectError;
 pub use execution_step::UncatchableError;
 pub use polyplets::ResolvedTriplet;
 pub use polyplets::SecurityTetraplet;

air/tests/test_module/instructions/fail.rs

@@ -58,13 +58,15 @@ fn fail_with_literals() {
             )"#,
     );
 
-    let result = call_vm!(vm, "", script, "", "");
+    let init_peer_id = "init_peer_id";
+    let result = call_vm!(vm, init_peer_id, script, "", "");
 
     let expected_error = CatchableError::UserError {
         error: rc!(json!( {
         "error_code": 1337i64,
         "instruction": "fail 1337 error message",
         "message": "error message",
+        "peer_id": init_peer_id,
         })),
     };
     assert!(check_error(&result, expected_error));

air/tests/test_module/integration/last_error.rs

@@ -14,7 +14,11 @@
  * limitations under the License.
  */
 
-use air::{CatchableError, ExecutionError, LambdaError, SecurityTetraplet};
+use air::CatchableError;
+use air::ExecutionError;
+use air::LambdaError;
+use air::LastErrorObjectError;
+use air::SecurityTetraplet;
 use air_test_utils::prelude::*;
 
 use fstrings::f;
@@ -324,3 +328,169 @@ fn last_error_with_par_one_subtree_failed() {
     });
     assert_eq!(actual_value, expected_value);
 }
+
+#[test]
+fn fail_with_scalar_rebubble_error() {
+    let fallible_peer_id = "fallible_peer_id";
+    let mut fallible_vm = create_avm(fallible_call_service("fallible_call_service"), fallible_peer_id);
+
+    let script = f!(r#"
+        (xor
+            (call "{fallible_peer_id}" ("fallible_call_service" "") [""])
+            (seq
+                (ap %last_error% scalar)
+                (fail scalar)
+            )
+        )
+    "#);
+
+    let result = call_vm!(fallible_vm, "", &script, "", "");
+
+    let expected_error = CatchableError::UserError {
+        error: rc!(json!({
+            "error_code": 10000i64,
+            "instruction": r#"call "fallible_peer_id" ("fallible_call_service" "") [""] "#,
+            "message": r#"Local service error, ret_code is 1, error message is '"failed result from fallible_call_service"'"#,
+            "peer_id": "fallible_peer_id",
+        })),
+    };
+    assert!(check_error(&result, expected_error));
+}
+
+#[test]
+fn fail_with_scalar_from_call() {
+    let vm_peer_id = "vm_peer_id";
+    let error_code = 1337;
+    let error_message = "error message";
+    let service_result = json!({"error_code": error_code, "message": error_message});
+    let mut vm = create_avm(set_variable_call_service(service_result), vm_peer_id);
+
+    let script = f!(r#"
+        (seq
+            (call "{vm_peer_id}" ("" "") [""] scalar)
+            (fail scalar)
+        )
+    "#);
+
+    let result = call_vm!(vm, "", &script, "", "");
+
+    let expected_error = CatchableError::UserError {
+        error: rc!(json!({
+            "error_code": error_code,
+            "message": error_message,
+        })),
+    };
+    assert!(check_error(&result, expected_error));
+}
+
+#[test]
+fn fail_with_scalar_with_lambda_from_call() {
+    let vm_peer_id = "vm_peer_id";
+    let error_code = 1337;
+    let error_message = "error message";
+    let service_result = json!({"error": {"error_code": error_code, "message": error_message}});
+    let mut vm = create_avm(set_variable_call_service(service_result), vm_peer_id);
+
+    let script = f!(r#"
+        (seq
+            (call "{vm_peer_id}" ("" "") [""] scalar)
+            (fail scalar.$.error)
+        )
+    "#);
+
+    let result = call_vm!(vm, "", &script, "", "");
+
+    let expected_error = CatchableError::UserError {
+        error: rc!(json!({
+            "error_code": error_code,
+            "message": error_message,
+        })),
+    };
+    assert!(check_error(&result, expected_error));
+}
+
+#[test]
+fn fail_with_scalar_from_call_not_enough_fields() {
+    let vm_peer_id = "vm_peer_id";
+    let error_code = 1337;
+    let service_result = json!({ "error_code": error_code });
+    let mut vm = create_avm(set_variable_call_service(service_result.clone()), vm_peer_id);
+
+    let script = f!(r#"
+        (seq
+            (call "{vm_peer_id}" ("" "") [""] scalar)
+            (fail scalar)
+        )
+    "#);
+
+    let result = call_vm!(vm, "", &script, "", "");
+
+    let expected_error = CatchableError::InvalidLastErrorObjectError(LastErrorObjectError::ScalarMustContainField {
+        scalar: service_result,
+        field_name: "message",
+    });
+    assert!(check_error(&result, expected_error));
+}
+
+#[test]
+fn fail_with_scalar_from_call_not_right_type() {
+    let vm_peer_id = "vm_peer_id";
+    let service_result = json!([]);
+    let mut vm = create_avm(set_variable_call_service(service_result.clone()), vm_peer_id);
+
+    let script = f!(r#"
+        (seq
+            (call "{vm_peer_id}" ("" "") [""] scalar)
+            (fail scalar)
+        )
+    "#);
+
+    let result = call_vm!(vm, "", &script, "", "");
+
+    let expected_error =
+        CatchableError::InvalidLastErrorObjectError(LastErrorObjectError::ScalarMustBeObject(service_result));
+    assert!(check_error(&result, expected_error));
+}
+
+#[test]
+fn fail_with_scalar_from_call_field_not_right_type() {
+    let vm_peer_id = "vm_peer_id";
+    let service_result = json!({"error_code": "error_code", "message": "error message"});
+    let mut vm = create_avm(set_variable_call_service(service_result.clone()), vm_peer_id);
+
+    let script = f!(r#"
+        (seq
+            (call "{vm_peer_id}" ("" "") [""] scalar)
+            (fail scalar)
+        )
+    "#);
+
+    let result = call_vm!(vm, "", &script, "", "");
+
+    let expected_error = CatchableError::InvalidLastErrorObjectError(LastErrorObjectError::ScalarFieldIsWrongType {
+        scalar: service_result.clone(),
+        field_name: "error_code",
+        expected_type: "integer",
+    });
+    assert!(check_error(&result, expected_error));
+}
+
+#[test]
+fn last_error_with_match() {
+    let vm_peer_id = "vm_peer_id";
+    let mut vm = create_avm(fallible_call_service("fallible_call_service"), vm_peer_id);
+
+    let script = f!(r#"
+        (xor
+            (call "{vm_peer_id}" ("fallible_call_service" "") [""])
+            (match %last_error%.$.error_code 10000
+                (call "{vm_peer_id}" ("" "") [%last_error%])
+            )
+        )
+    "#);
+
+    let result = checked_call_vm!(vm, "asd", &script, "", "");
+
+    let trace = trace_from_result(&result);
+    assert_eq!(trace.len(), 2); // if match works there will be 2 calls in a resulted trace
+}

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

@@ -88,6 +88,7 @@ pub struct MisMatch<'i> {
 /// (fail %last_error%)
 #[derive(Serialize, Debug, PartialEq)]
 pub enum Fail<'i> {
+    Scalar(ScalarWithLambda<'i>),
     Literal {
         ret_code: i64,
         error_message: &'i str,

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

@@ -36,7 +36,7 @@ impl fmt::Display for Instruction<'_> {
             Next(next) => write!(f, "{}", next),
             New(new) => write!(f, "{}", new),
             Null(null) => write!(f, "{}", null),
-            Error => Ok(()),
+            Error => write!(f, "error"),
         }
     }
 }
@@ -59,6 +59,7 @@ impl fmt::Display for Ap<'_> {
 impl fmt::Display for Fail<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
+            Fail::Scalar(scalar) => write!(f, "fail {}", scalar),
             Fail::Literal {
                 ret_code,
                 error_message,

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

@@ -136,6 +136,8 @@ ScriptVariable: Variable<'input> = {
 };
 
 FailBody: Fail<'input> = {
+    <scalar:Scalar> => Fail::Scalar(ScalarWithLambda::new(scalar.0, None, scalar.1)),
+    <scalar:ScalarWithLambda> => Fail::Scalar(ScalarWithLambda::new(scalar.0, Some(scalar.1), scalar.2)),
     <ret_code:I64> <error_message:Literal> => Fail::Literal {
         ret_code,
         error_message,

crates/air-lib/air-parser/src/parser/tests/dsl.rs

@@ -69,6 +69,10 @@ pub(super) fn null() -> Instruction<'static> {
     Instruction::Null(Null)
 }
 
+pub(super) fn fail_scalar(scalar: ScalarWithLambda) -> Instruction<'_> {
+    Instruction::Fail(Fail::Scalar(scalar))
+}
+
 pub(super) fn fail_literals(ret_code: i64, error_message: &str) -> Instruction<'_> {
     Instruction::Fail(Fail::Literal {
         ret_code,

crates/air-lib/air-parser/src/parser/tests/fail.rs

@@ -16,6 +16,10 @@
 
 use super::dsl::*;
 use super::parse;
+use crate::ast::ScalarWithLambda;
+
+use air_lambda_ast::LambdaAST;
+use air_lambda_ast::ValueAccessor;
 
 #[test]
 fn parse_fail_last_error() {
@@ -36,3 +40,31 @@ fn parse_fail_literals() {
     let expected = fail_literals(1, "error message");
     assert_eq!(instruction, expected)
 }
+
+#[test]
+fn parse_fail_scalars() {
+    let source_code = r#"
+           (fail scalar)
+        "#;
+    let instruction = parse(source_code);
+    let expected = fail_scalar(ScalarWithLambda::new("scalar", None, 18));
+    assert_eq!(instruction, expected)
+}
+
+#[test]
+fn parse_fail_scalar_with_lambda() {
+    let source_code = r#"
+           (fail scalar.$.field_accessor)
+        "#;
+    let instruction = parse(source_code);
+    let expected = fail_scalar(ScalarWithLambda::new(
+        "scalar",
+        Some(unsafe {
+            LambdaAST::new_unchecked(vec![ValueAccessor::FieldAccessByName {
+                field_name: "field_accessor",
+            }])
+        }),
+        18,
+    ));
+    assert_eq!(instruction, expected)
+}