fix: user-friendly errors for undefined FunC functions (tact-lang#587)

CHANGELOG.md

@@ -47,6 +47,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Error messages for unicode code points outside of valid range: PR [#535](https://github.com/tact-lang/tact/pull/535)
 - Correct regex for unicode code points and escaping of control codes in generated comments: PR [#535](https://github.com/tact-lang/tact/pull/535)
 - Add `impure` specifier to some stdlib functions that are expected to throw errors: PR [#565](https://github.com/tact-lang/tact/pull/565)
+- Defining non-existing native FunC functions now throws an understandable compilation error: PR [#585](https://github.com/tact-lang/tact/pull/585)
 
 ## [1.4.0] - 2024-06-21
 

src/pipeline/build.ts

@@ -180,6 +180,16 @@ export async function build(args: {
                 logger,
             });
             if (!c.ok) {
+                const match = c.log.match(
+                    /undefined function `([^`]+)`, defining a global function of unknown type/,
+                );
+                if (match) {
+                    const message = `Function '${match[1]}' does not exist in imported FunC sources`;
+                    logger.error(message);
+                    errorMessages.push(new Error(message));
+                    return { ok: false, error: errorMessages };
+                }
+
                 logger.error(c.log);
                 ok = false;
                 errorMessages.push(new Error(c.log));

src/test/compilation-failed/contracts/func-function-does-not-exist.tact

@@ -0,0 +1,8 @@
+@name(iDoNotExist)
+native youDo();
+
+contract Test {
+   get fun test() {
+       youDo();
+   }
+}

src/test/compilation-failed/func-errors.spec.ts

@@ -0,0 +1,14 @@
+import { __DANGER_resetNodeId } from "../../grammar/ast";
+import { itShouldNotCompile } from "./util";
+
+describe("func-errors", () => {
+    beforeEach(() => {
+        __DANGER_resetNodeId();
+    });
+
+    itShouldNotCompile({
+        testName: "func-function-does-not-exist",
+        errorMessage:
+            "Function 'iDoNotExist' does not exist in imported FunC sources",
+    });
+});

src/test/compilation-failed/tact.config.json

@@ -131,6 +131,11 @@
       "name": "contract-duplicate-receiver-opcode",
       "path": "./contracts/contract-duplicate-receiver-opcode.tact",
       "output": "./contracts/output"
+    },
+    {
+      "name": "func-function-does-not-exist",
+      "path": "./contracts/func-function-does-not-exist.tact",
+      "output": "./contracts/output"
     }
   ]
 }