fix: Fix race condition issue

The `markdown` singleton was causing
race conditions while testing.
The code is simplified,
and the Markdown converter
is instantiated by each formatter.

src/markdown_exec/formatters/base.py

@@ -9,7 +9,7 @@
 from markupsafe import Markup
 
 from markdown_exec.logger import get_logger
-from markdown_exec.rendering import add_source, code_block, markdown
+from markdown_exec.rendering import MarkdownConverter, add_source, code_block
 
 logger = get_logger(__name__)
 
@@ -41,7 +41,7 @@ def base_format(  # noqa: WPS231
     Returns:
         HTML contents.
     """
-    markdown.setup(md)
+    markdown = MarkdownConverter(md)
     extra = options.get("extra", {})
     try:
         output = run(code, **extra)

src/markdown_exec/formatters/console.py

@@ -10,7 +10,7 @@
 
 from markdown_exec.formatters.sh import _run_sh  # noqa: WPS450
 from markdown_exec.logger import get_logger
-from markdown_exec.rendering import add_source, code_block, markdown
+from markdown_exec.rendering import MarkdownConverter, add_source, code_block
 
 logger = get_logger(__name__)
 
@@ -24,7 +24,7 @@ def _format_console(  # noqa: WPS231
     tabs: tuple[str, str],
     **options: Any,
 ) -> str:
-    markdown.setup(md)
+    markdown = MarkdownConverter(md)
 
     sh_lines = []
     for line in code.split("\n"):

src/markdown_exec/formatters/pycon.py

@@ -10,7 +10,7 @@
 
 from markdown_exec.formatters.python import _run_python  # noqa: WPS450
 from markdown_exec.logger import get_logger
-from markdown_exec.rendering import add_source, code_block, markdown
+from markdown_exec.rendering import MarkdownConverter, add_source, code_block
 
 logger = get_logger(__name__)
 
@@ -24,7 +24,7 @@ def _format_pycon(  # noqa: WPS231
     tabs: tuple[str, str],
     **options: Any,
 ) -> str:
-    markdown.setup(md)
+    markdown = MarkdownConverter(md)
 
     python_lines = []
     for line in code.split("\n"):

src/markdown_exec/formatters/tree.py

@@ -7,7 +7,7 @@
 
 from markdown import Markdown
 
-from markdown_exec.rendering import code_block, markdown
+from markdown_exec.rendering import MarkdownConverter, code_block
 
 
 def _rec_build_tree(lines: list[str], parent: list, offset: int, base_indent: int):
@@ -62,6 +62,6 @@ def _format_tree(  # noqa: WPS231
     tabs: tuple[str, str],
     **options: Any,
 ) -> str:
-    markdown.setup(md)
+    markdown = MarkdownConverter(md)
     output = "\n".join(_rec_format_tree(_build_tree(code)))
     return markdown.convert(code_block(result or "bash", output))

src/markdown_exec/rendering.py

@@ -128,28 +128,25 @@ def run(self, root: Element):  # noqa: D102,WPS231
 
 
 def _mimic(md: Markdown) -> Markdown:
+    md = getattr(md, "_original_md", md)
     new_md = Markdown()  # noqa: WPS442
     new_md.registerExtensions(md.registeredExtensions + ["tables", "md_in_html"], {})
     new_md.treeprocessors.register(
         _IdPrependingTreeprocessor(md, ""),
         _IdPrependingTreeprocessor.name,
         priority=4,  # right after 'toc' (needed because that extension adds ids to headers)
     )
+    new_md._original_md = md  # type: ignore[attr-defined]  # noqa: WPS437
     return new_md
 
 
-class _MarkdownConverter:
+class MarkdownConverter:
     """Helper class to avoid breaking the original Markdown instance state."""
 
-    def __init__(self) -> None:  # noqa: D107
-        self._md_ref: Markdown = None  # type: ignore[assignment]
-        self._md_stack: list[Markdown] = []
-        self._counter: int = 0
-        self._level: int = 0
+    counter: int = 0
 
-    def setup(self, md: Markdown) -> None:
-        if not self._md_ref:
-            self._md_ref = md
+    def __init__(self, md: Markdown) -> None:  # noqa: D107
+        self._md_ref: Markdown = md
 
     def convert(self, text: str, stash: dict[str, str] | None = None) -> Markup:
         """Convert Markdown text to safe HTML.
@@ -161,34 +158,19 @@ def convert(self, text: str, stash: dict[str, str] | None = None) -> Markup:
         Returns:
             Safe HTML.
         """
-        # store current md instance
-        md = self._md
-        self._level += 1
+        md = _mimic(self._md_ref)
 
         # prepare for conversion
-        md.treeprocessors[_IdPrependingTreeprocessor.name].id_prefix = f"exec-{self._counter}--"
-        self._counter += 1
+        md.treeprocessors[_IdPrependingTreeprocessor.name].id_prefix = f"exec-{MarkdownConverter.counter}--"
+        MarkdownConverter.counter += 1
 
         try:  # noqa: WPS501
             converted = md.convert(text)
         finally:
-            self._level -= 1
             md.treeprocessors[_IdPrependingTreeprocessor.name].id_prefix = ""
 
         # restore html from stash
         for placeholder, stashed in (stash or {}).items():
             converted = converted.replace(placeholder, stashed)
 
         return Markup(converted)
-
-    @property
-    def _md(self) -> Markdown:
-        try:
-            return self._md_stack[self._level]
-        except IndexError:
-            self._md_stack.append(_mimic(self._md_ref))
-            return self._md
-
-
-# provide a singleton
-markdown = _MarkdownConverter()