Support installing pyemscripten platform wheels

CHANGELOG.md

@@ -6,12 +6,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## [0.11.1] - 2026/04/02
+
 ### Fixed
 
 - Fixed content-type header parsing to handle PyPI mirrors that include charset parameters.
   This improves compatibility with mirrors that return headers like `application/json; charset=utf-8`.
   [#261](https://github.com/pyodide/micropip/pull/261)
 
+### Changed
+
+- micropip now accepts `pyemscripten` platform wheels in addition to `pyodide` platform wheels,
+  following the PEP 783 standard.
+  [#270](https://github.com/pyodide/micropip/pull/270)
+
 ## [0.11.0] - 2025/10/18
 
 ### Added

micropip/_utils.py

@@ -69,12 +69,25 @@ def get_files_in_distribution(dist: Distribution) -> set[Path]:
 
 @functools.cache
 def sys_tags() -> tuple[Tag, ...]:
-    new_tags = []
-    abi_version = get_config_var("PYODIDE_ABI_VERSION")
-    pyodide_platform_tag = f"pyodide_{abi_version}_wasm32"
+    new_tags: list[Tag] = []
+
+    abi_version = get_config_var("PYEMSCRIPTEN_PLATFORM_VERSION")
+    if not abi_version:
+        # Fallback to PYODIDE_ABI_VERSION for compatibility
+        abi_version = get_config_var("PYODIDE_ABI_VERSION")
+
+    pyodide_platform_tags = [
+        # PEP 783
+        f"pyemscripten_{abi_version}_wasm32",
+        # for backward compatibility
+        f"pyodide_{abi_version}_wasm32",
+    ]
     for tag in sys_tags_orig():
         if "emscripten" in tag.platform:
-            new_tags.append(Tag(tag.interpreter, tag.abi, pyodide_platform_tag))
+            new_tags.extend(
+                Tag(tag.interpreter, tag.abi, pyodide_platform_tag)
+                for pyodide_platform_tag in pyodide_platform_tags
+            )
         new_tags.append(tag)
     return tuple(new_tags)
 

tests/test_utils.py

@@ -210,3 +210,41 @@ def test_constrain_requirement_direct_url(valid_constraint, wheel_catalog):
     assert not msg
     constrained = _utils.constrain_requirement(req, constrained_reqs)
     assert constrained.url == url
+
+
+@run_in_pyodide
+def test_sys_tags_pep783_both_tags_present(selenium_standalone_micropip):
+    """sys_tags() should produce both pyemscripten_ and pyodide_ platform tags."""
+    from sysconfig import get_config_var
+
+    from micropip._utils import sys_tags
+
+    version = get_config_var("PYEMSCRIPTEN_PLATFORM_VERSION")
+    if not version:
+        version = get_config_var("PYODIDE_ABI_VERSION")
+
+    tags = list(sys_tags())
+    pyemscripten_tags = [
+        t for t in tags if t.platform == f"pyemscripten_{version}_wasm32"
+    ]
+    pyodide_tags = [t for t in tags if t.platform == f"pyodide_{version}_wasm32"]
+
+    assert len(pyemscripten_tags) > 0, "No pyemscripten_ tags found"
+    assert len(pyodide_tags) > 0, "No pyodide_ tags found"
+
+
+@run_in_pyodide
+def test_check_compatible_pyemscripten_wheel(selenium_standalone_micropip):
+    """Wheels tagged with pyemscripten_ platform should be compatible in Pyodide."""
+    from sys import version_info
+    from sysconfig import get_config_var
+
+    from micropip._utils import check_compatible
+
+    version = get_config_var("PYEMSCRIPTEN_PLATFORM_VERSION")
+    if not version:
+        version = get_config_var("PYODIDE_ABI_VERSION")
+
+    cpver = f"cp{version_info.major}{version_info.minor}"
+    wheel_name = f"pkg-1.0.0-{cpver}-{cpver}-pyemscripten_{version}_wasm32.whl"
+    check_compatible(wheel_name)  # should not raise