extmod/asyncio/uasyncio.py: Add backwards-compatible uasyncio alias.

This allows existing code that does `import uasyncio` or
`import uasyncio as asyncio` to continue working.

It uses the same lazy-loading as asyncio to prevent loading of unused
features.

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

extmod/asyncio/manifest.py

@@ -13,3 +13,6 @@
     base_path="..",
     opt=3,
 )
+
+# Backwards-compatible uasyncio module.
+module("uasyncio.py", opt=3)

extmod/asyncio/uasyncio.py

@@ -0,0 +1,8 @@
+# This module just allows `import uasyncio` to work. It lazy-loads from
+# `asyncio` without duplicating its globals dict.
+
+
+def __getattr__(attr):
+    import asyncio
+
+    return getattr(asyncio, attr)

tests/extmod/asyncio_as_uasyncio.py

@@ -0,0 +1,12 @@
+try:
+    import uasyncio
+    import asyncio
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+x = set(dir(uasyncio))
+y = set(dir(asyncio)) - set(["event", "lock", "stream", "funcs"])
+
+print(x - y)
+print(y - x)

tests/extmod/asyncio_as_uasyncio.py.exp

@@ -0,0 +1,2 @@
+set()
+set()