Fix: add missing int64 <-> bigint primitive mapping when generating TypeScript definitions (#20451)

This PR adds a missing mapping between int64_t <=> bigint that makes the typings generation fail for code that makes use of that primitive type.

Author: Dabolus

site/source/docs/porting/connecting_cpp_and_javascript/embind.rst

@@ -917,13 +917,19 @@ Out of the box, *embind* provides converters for many standard C++ types:
 +---------------------+--------------------------------------------------------------------+
 | ``double``          | Number                                                             |
 +---------------------+--------------------------------------------------------------------+
+| ``int64_t``         | BigInt*                                                            |
++---------------------+--------------------------------------------------------------------+
+| ``uint64_t``        | BigInt*                                                            |
++---------------------+--------------------------------------------------------------------+
 | ``std::string``     | ArrayBuffer, Uint8Array, Uint8ClampedArray, Int8Array, or String   |
 +---------------------+--------------------------------------------------------------------+
 | ``std::wstring``    | String (UTF-16 code units)                                         |
 +---------------------+--------------------------------------------------------------------+
 | ``emscripten::val`` | anything                                                           |
 +---------------------+--------------------------------------------------------------------+
 
+\*Requires BigInt support to be enabled with the `-sWASM_BIGINT` flag.
+
 For convenience, *embind* provides factory functions to register
 ``std::vector<T>`` (:cpp:func:`register_vector`) and ``std::map<K, V>``
 (:cpp:func:`register_map`) types:

src/embind/embind_ts.js

@@ -210,6 +210,10 @@ var LibraryEmbind = {
         ['bool', 'boolean'],
         ['float', 'number'],
         ['double', 'number'],
+#if WASM_BIGINT
+        ['int64_t', 'bigint'],
+        ['uint64_t', 'bigint'],
+#endif
         ['void', 'void'],
         ['std::string', jsString],
         ['std::basic_string<unsigned char>', jsString],

test/other/embind_tsgen_bigint.cpp

@@ -0,0 +1,10 @@
+#include <emscripten/bind.h>
+#include <emscripten/val.h>
+
+using namespace emscripten;
+
+uint64_t bigint_fn(int64_t) { return 0; }
+
+EMSCRIPTEN_BINDINGS(Test) {
+  function("bigintFn", &bigint_fn);
+}

test/other/embind_tsgen_bigint.d.ts

@@ -0,0 +1,3 @@
+export interface MainModule {
+  bigintFn(_0: bigint): bigint;
+}

test/test_other.py

@@ -2990,6 +2990,15 @@ def test_embind_tsgen_val(self):
                       '-lembind', '--embind-emit-tsd', 'embind_tsgen_val.d.ts'])
     self.assertExists('embind_tsgen_val.d.ts')
 
+  def test_embind_tsgen_bigint(self):
+    args = [EMCC, test_file('other/embind_tsgen_bigint.cpp'), '-lembind', '--embind-emit-tsd', 'embind_tsgen_bigint.d.ts']
+    # Check that TypeScript generation fails when code contains bigints but their support is not enabled
+    stderr = self.expect_fail(args)
+    self.assertContained("Missing primitive type to TS type for 'int64_t", stderr)
+    # Check that TypeScript generation works when bigint support is enabled
+    self.run_process(args + ['-sWASM_BIGINT'])
+    self.assertFileContents(test_file('other/embind_tsgen_bigint.d.ts'), read_file('embind_tsgen_bigint.d.ts'))
+
   def test_emconfig(self):
     output = self.run_process([emconfig, 'LLVM_ROOT'], stdout=PIPE).stdout.strip()
     self.assertEqual(output, config.LLVM_ROOT)