don't call asyncio.run for async handling

docs/changelog.md

@@ -1,5 +1,9 @@
 # Changelog
 
+### 0.10.3 - Bugfixes
+
+-  Don't use `asyncio.run` for async handling. Fixes [#93](https://github.com/smarie/mkdocs-gallery/issues/93).
+
 ### 0.10.2 - Bugfixes
 
 - **SECURITY** removed insecure polyfill extra javascript from example. Fixes [#99](https://github.com/smarie/mkdocs-gallery/issues/99).

docs/examples/plot_12_async.py → examples/plot_12_async.py

@@ -31,16 +31,9 @@ async def afn():
 
 # %%
 # Without any handling, the snippet above would trigger a `SyntaxError`, since we are using `await` outside of an
-# asynchronous context. With the handling, it works just fine.
+# asynchronous context. With the background handling, it works just fine.
 #
-# The background handling will only be applied if it is actually needed. Meaning, you can still run your asynchronous
-# code manually if required.
-
-asyncio.run(afn())
-
-
-# %%
-# Apart from `await` all other asynchronous syntax is supported as well.
+# Apart from `await` that we used above, all other asynchronous syntax is supported as well.
 #
 # ## Asynchronous Generators
 

src/mkdocs_gallery/gen_single.py

@@ -41,7 +41,7 @@
 from .notebook import jupyter_notebook, save_notebook
 from .py_source_parser import remove_config_comments, split_code_and_text_blocks
 from .scrapers import ImageNotFoundError, _find_image_ext, clean_modules, save_figures
-from .utils import _new_file, _replace_by_new_if_needed, optipng, rescale_image
+from .utils import _new_file, _replace_by_new_if_needed, optipng, rescale_image, run_async
 
 logger = mkdocs_compatibility.getLogger("mkdocs-gallery")
 
@@ -780,8 +780,7 @@ def _apply_async_handling(code_ast, *, compiler_flags):
                 async def __async_wrapper__():
                     # original AST goes here
                     return locals()
-                import asyncio as __asyncio__
-                __async_wrapper_locals__ = __asyncio__.run(__async_wrapper__())
+                __async_wrapper_locals__ = __run_async__(__async_wrapper__())
                 __async_wrapper_result__ = __async_wrapper_locals__.pop("__async_wrapper_result__", None)
                 globals().update(__async_wrapper_locals__)
                 __async_wrapper_result__
@@ -950,6 +949,7 @@ def parse_and_execute(script: GalleryScript, script_blocks):
             # Don't ever support __file__: Issues #166 #212
             # Don't let them use input()
             "input": _check_input,
+            "__run_async__": run_async,
         }
     )
     script.run_vars.example_globals = example_globals
@@ -960,7 +960,7 @@ def parse_and_execute(script: GalleryScript, script_blocks):
     # Remember the original argv so that we can put them back after run
     argv_orig = sys.argv[:]
 
-    # Remember the original sys.path so that we can reset it after run
+    # Remember the original sys.path so that we can reset it after run
     sys_path_orig = deepcopy(sys.path)
 
     # Python file is the original one (not the copy for download)

src/mkdocs_gallery/utils.py

@@ -12,6 +12,7 @@
 
 from __future__ import absolute_import, division, print_function
 
+import asyncio
 import hashlib
 import os
 import re
@@ -376,3 +377,15 @@ def is_relative_to(parentpath: Path, subpath: Path) -> bool:
 
     except ValueError:
         return False
+
+
+def run_async(coro):
+    try:
+        loop = asyncio.get_running_loop()
+    except RuntimeError:
+        loop = asyncio.new_event_loop()
+
+    try:
+        return loop.run_until_complete(coro)
+    finally:
+        loop.close()

tests/test_gen_single.py

@@ -1,45 +1,47 @@
 import ast
+import asyncio
 import codeop
 import sys
 from textwrap import dedent
 
 import pytest
 
 from mkdocs_gallery.gen_single import _needs_async_handling, _parse_code
+from mkdocs_gallery.utils import run_async
 
 SRC_FILE = __file__
 COMPILER = codeop.Compile()
-COMPILER_FLAGS = codeop.Compile().flags
+COMPILER_FLAGS = COMPILER.flags
 
 
 needs_ast_unparse = pytest.mark.skipif(
     sys.version_info < (3, 9), reason="ast.unparse is only available for Python >= 3.9"
 )
 
 
+def make_globals():
+    return {"__run_async__": run_async}
+
+
 def test_non_async_syntax_error():
     with pytest.raises(SyntaxError, match="unexpected indent"):
         _parse_code("foo = None\n bar = None", src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS)
 
 
+@needs_ast_unparse
+def test_no_async_roundtrip():
+    code = "None"
+    assert not _needs_async_handling(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS)
+
+    code_unparsed = ast.unparse(_parse_code(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS))
+
+    assert code_unparsed == code
+
+
 @needs_ast_unparse
 @pytest.mark.parametrize(
-    ("code", "needs"),
+    "code",
     [
-        pytest.param("None", False, id="no_async"),
-        pytest.param(
-            dedent(
-                """
-                async def afn():
-                    return True
-
-                import asyncio
-                assert asyncio.run(afn())
-                """
-            ),
-            False,
-            id="asyncio_run",
-        ),
         pytest.param(
             dedent(
                 """
@@ -49,7 +51,6 @@ async def afn():
                 assert await afn()
                 """
             ),
-            True,
             id="await",
         ),
         pytest.param(
@@ -62,7 +63,6 @@ async def agen():
                     assert item
                 """
             ),
-            True,
             id="async_for",
         ),
         pytest.param(
@@ -74,7 +74,6 @@ async def agen():
                 assert [item async for item in agen()] == [True]
                 """
             ),
-            True,
             id="async_comprehension",
         ),
         pytest.param(
@@ -90,25 +89,23 @@ async def acm():
                     assert ctx
                 """
             ),
-            True,
             id="async_context_manager",
         ),
     ],
 )
-def test_async_handling(code, needs):
-    assert _needs_async_handling(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS) is needs
+def test_async_handling(code):
+    assert _needs_async_handling(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS)
 
     # Since AST objects are quite involved to compare, we unparse again and check that nothing has changed. Note that
     # since we are dealing with AST and not CST here, all whitespace is eliminated in the process and this needs to be
     # reflected in the input as well.
     code_stripped = "\n".join(line for line in code.splitlines() if line)
     code_unparsed = ast.unparse(_parse_code(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS))
-    assert (code_unparsed == code_stripped) ^ needs
+    assert code_unparsed != code_stripped
 
-    if needs:
-        assert not _needs_async_handling(code_unparsed, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS)
+    assert not _needs_async_handling(code_unparsed, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS)
 
-    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), {})
+    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), make_globals())
 
 
 @needs_ast_unparse
@@ -128,10 +125,10 @@ async def afn():
     )
     code_unparsed = ast.unparse(_parse_code(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS))
 
-    locals = {}
-    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), locals)
+    globals_ = make_globals()
+    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), globals_)
 
-    assert "sentinel" in locals and locals["sentinel"] == sentinel
+    assert "sentinel" in globals_ and globals_["sentinel"] == sentinel
 
 
 @needs_ast_unparse
@@ -153,6 +150,24 @@ async def afn():
     last = code_unparsed_ast.body[-1]
     assert isinstance(last, ast.Expr)
 
-    locals = {}
-    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), locals)
-    assert eval(ast.unparse(last.value), locals)
+    globals_ = make_globals()
+    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), globals_)
+    assert eval(ast.unparse(last.value), globals_)
+
+
+@needs_ast_unparse
+def test_get_event_loop_after_async_handling():
+    # Non-regression test for https://github.com/smarie/mkdocs-gallery/issues/93
+    code = dedent(
+        """
+        async def afn():
+            return True
+
+        assert await afn()
+        """
+    )
+
+    code_unparsed = ast.unparse(_parse_code(code, src_file=SRC_FILE, compiler_flags=COMPILER_FLAGS))
+    exec(COMPILER(code_unparsed, SRC_FILE, "exec"), make_globals())
+
+    asyncio.events.get_event_loop()