From: Dmitry Volyntsev <xeioex@nginx.com>
Date: Thu, 2 Jun 2022 23:32:38 +0000 (-0700)
Subject: Fixed njs_vmcode_interpreter() when await fails.
X-Git-Tag: 0.7.5~19
X-Git-Url: http://git.kaiwu.me/postgresql/log/contrib/postgres_fdw/postgres_fdw.c?a=commitdiff_plain;h=d09868bc71f9a990445959329ad8c1b10d3898f5;p=njs.git

Fixed njs_vmcode_interpreter() when await fails.

Previously, while interpreting a user function, njs_vmcode_interpreter()
might return prematurely when an error happens in await instruction.
This is not correct because the current frame has to be unwound (or
exception caught) first.

The fix is to exit through only 5 appropriate exit points to ensure
proper unwinding.

The patch correctly fixes issue reported in 07ef6c1f04f1 (0.7.3).

This closes #506 issue on Github.
---

diff --git a/src/njs_vmcode.c b/src/njs_vmcode.c
index 9833ada0..cc33d20b 100644
--- a/src/njs_vmcode.c
+++ b/src/njs_vmcode.c
@@ -856,9 +856,15 @@ next:
             case NJS_VMCODE_AWAIT:
                 await = (njs_vmcode_await_t *) pc;
 
+                ret = njs_vmcode_await(vm, await, promise_cap, async_ctx);
+
                 njs_vmcode_debug(vm, pc, "EXIT AWAIT");
 
-                return njs_vmcode_await(vm, await, promise_cap, async_ctx);
+                if (njs_slow_path(ret == NJS_ERROR)) {
+                    goto error;
+                }
+
+                return ret;
 
             case NJS_VMCODE_TRY_START:
                 ret = njs_vmcode_try_start(vm, value1, value2, pc);
@@ -1923,6 +1929,7 @@ njs_vmcode_await(njs_vm_t *vm, njs_vmcode_await_t *await,
 
     value = njs_scope_valid_value(vm, await->retval);
     if (njs_slow_path(value == NULL)) {
+        njs_internal_error(vm, "await->retval is invalid");
         return NJS_ERROR;
     }
 
diff --git a/test/js/async_exception_in_await.t.js b/test/js/async_exception_in_await.t.js
new file mode 100644
index 00000000..cc9bc8ab
--- /dev/null
+++ b/test/js/async_exception_in_await.t.js
@@ -0,0 +1,22 @@
+/*---
+includes: []
+flags: []
+---*/
+
+var p = new Promise(() => 0);
+Object.defineProperty(p, "constructor", {get: () => ({}).a.a});
+
+async function g() {
+    try {
+        await p;
+    } catch (e) {
+    }
+}
+
+function f() {
+    g();
+
+    return 42;
+}
+
+assert.sameValue(f(), 42);