fix: whitespace discrepancies on round trip conversions

frontend/src/core/codemirror/language/languages/markdown.ts

@@ -103,6 +103,9 @@ export class MarkdownLanguageAdapter
     code: string,
     metadata: MarkdownLanguageAdapterMetadata,
   ): [string, number] {
+    // NB. Must be kept consistent with marimo/_convert/utils.py
+    // ::markdown_to_marimo
+
     // Empty string
     if (code === "") {
       // Need at least a space, otherwise the output will be 6 quotes

marimo/_convert/markdown/markdown.py

@@ -247,7 +247,7 @@ def _tree_to_ir(root: Element) -> SafeWrap[NotebookSerializationV1]:
     header = root.get("header", None)
     pyproject = root.get("pyproject", None)
     if pyproject and not header:
-        header = "\n# ".join(["# ///script", *pyproject.splitlines(), "///"])
+        header = "\n# ".join(["# /// script", *pyproject.splitlines(), "///"])
     notebook = NotebookSerializationV1(
         app=AppInstantiation(options=app_config),
         cells=[

marimo/_convert/utils.py

@@ -5,14 +5,25 @@
 
 
 def markdown_to_marimo(source: str) -> str:
+    # NB. This should be kept in sync with the logic in
+    # frontend/src/core/codemirror/language/languages/markdown.ts
+    # ::transformOut
     source = source.replace('"""', '\\"\\"\\"')
+
+    # 6 quotes in a row breaks
+    if not source:
+        source = " "
+
+    if "\n" not in source:
+        return f'mo.md(r"""{source}""")'
+
     return "\n".join(
         [
             "mo.md(",
             # r-string: a backslash is just a backslash!
             codegen.indent_text('r"""'),
-            codegen.indent_text(source),
-            codegen.indent_text('"""'),
+            source,
+            '"""',
             ")",
         ]
     )

marimo/_server/export/exporter.py

@@ -291,7 +291,7 @@ def export_as_md(
                 metadata["header"] = header.strip()
         else:
             header_file = previous if previous else filename
-            if header_file:
+            if header_file and Path(header_file).exists():
                 with open(header_file, encoding="utf-8") as f:
                     _metadata, _ = extract_frontmatter(f.read())
                 metadata.update(_metadata)

tests/_cli/snapshots/markdown_to_marimo.txt

@@ -8,10 +8,10 @@ app = marimo.App()
 def _(mo):
     mo.md(
         r"""
-        # Test Markdown
+    # Test Markdown
 
-        print('Hello from Markdown!')
-        """
+    print('Hello from Markdown!')
+    """
     )
     return
 

tests/_cli/snapshots/remote_markdown_to_marimo.txt

@@ -8,12 +8,12 @@ app = marimo.App()
 def _(mo):
     mo.md(
         r"""
-        # Remote Markdown Test
+    # Remote Markdown Test
 
-        ```python
-        print('Hello from Remote Markdown!')
-        ```
-        """
+    ```python
+    print('Hello from Remote Markdown!')
+    ```
+    """
     )
     return
 

tests/_convert/snapshots/basic_marimo_example.py.txt

@@ -0,0 +1,33 @@
+import marimo
+
+__generated_with = "0.15.2"
+app = marimo.App(width="medium")
+
+
+@app.cell(hide_code=True)
+def _(mo):
+    mo.md(r"""This is a simple marimo notebook""")
+    return
+
+
+@app.cell
+def _():
+    x = 1
+    return (x,)
+
+
+@app.cell
+def _(x):
+    y = x+1
+    y
+    return
+
+
+@app.cell
+def _():
+    import marimo as mo
+    return (mo,)
+
+
+if __name__ == "__main__":
+    app.run()

tests/_convert/snapshots/basic_marimo_example_roundtrip.py.txt

@@ -0,0 +1,33 @@
+import marimo
+
+__generated_with = "0.0.0"
+app = marimo.App(width="medium", app_title="Test Notebook")
+
+
+@app.cell(hide_code=True)
+def _(mo):
+    mo.md(r"""This is a simple marimo notebook""")
+    return
+
+
+@app.cell
+def _():
+    x = 1
+    return (x,)
+
+
+@app.cell
+def _(x):
+    y = x+1
+    y
+    return
+
+
+@app.cell
+def _():
+    import marimo as mo
+    return (mo,)
+
+
+if __name__ == "__main__":
+    app.run()

tests/_convert/snapshots/basic_marimo_example_to_md.txt

@@ -0,0 +1,20 @@
+---
+title: Test Notebook
+marimo-version: 0.0.0
+width: medium
+---
+
+This is a simple marimo notebook
+
+```python {.marimo}
+x = 1
+```
+
+```python {.marimo}
+y = x+1
+y
+```
+
+```python {.marimo}
+import marimo as mo
+```

tests/_convert/snapshots/convert_hides_markdown_cells.py.txt

@@ -5,33 +5,21 @@ app = marimo.App()
 
 @app.cell(hide_code=True)
 def _(mo):
-    mo.md(
-        r"""
-        A markdown cell.
-        """
-    )
+    mo.md(r"""A markdown cell.""")
     return
 
 
 @app.cell(hide_code=True)
 def _(mo):
     # Cell tags: blah
-    mo.md(
-        r"""
-        A markdown cell with tags: ['blah'].
-        """
-    )
+    mo.md(r"""A markdown cell with tags: ['blah'].""")
     return
 
 
 @app.cell(hide_code=True)
 def _(mo):
     # Cell tags: blah
-    mo.md(
-        r"""
-        A markdown cell with tags: ['blah', 'hide-cell'].
-        """
-    )
+    mo.md(r"""A markdown cell with tags: ['blah', 'hide-cell'].""")
     return
 
 

tests/_convert/snapshots/frontmatter-test.py.txt

@@ -9,11 +9,7 @@ app = marimo.App(app_title="My Title")
 
 @app.cell(hide_code=True)
 def _(mo):
-    mo.md(
-        r"""
-        # Notebook
-        """
-    )
+    mo.md(r"""# Notebook""")
     return
 
 

tests/_convert/snapshots/no-frontmatter.py.txt

@@ -6,11 +6,7 @@ app = marimo.App()
 
 @app.cell(hide_code=True)
 def _(mo):
-    mo.md(
-        r"""
-        # My Notebook
-        """
-    )
+    mo.md(r"""# My Notebook""")
     return
 
 
@@ -24,9 +20,9 @@ def _():
 def _(mo):
     mo.md(
         r"""
-        **Appendix**
-        - This is the end of the notebook
-        """
+    **Appendix**
+    - This is the end of the notebook
+    """
     )
     return
 

tests/_convert/snapshots/pypercent_format.py.txt

@@ -16,20 +16,16 @@ def _():
 def _(mo):
     mo.md(
         r"""
-        This is a markdown cell
-        with multiple lines
-        """
+    This is a markdown cell
+    with multiple lines
+    """
     )
     return
 
 
 @app.cell(hide_code=True)
 def _(mo):
-    mo.md(
-        r"""
-        This is a doc string, but also markdown
-        """
-    )
+    mo.md(r"""This is a doc string, but also markdown""")
     return
 
 

tests/_convert/snapshots/pypercent_markdown_only.py.txt

@@ -14,9 +14,9 @@ def _():
 def _(mo):
     mo.md(
         r"""
-        Introduction
-        This is a documentation file.
-        """
+    Introduction
+    This is a documentation file.
+    """
     )
     return
 
@@ -25,9 +25,9 @@ def _(mo):
 def _(mo):
     mo.md(
         r"""
-        Usage
-        Here's how to use this module.
-        """
+    Usage
+    Here's how to use this module.
+    """
     )
     return
 

tests/_convert/snapshots/sql-notebook.py.txt

@@ -6,11 +6,7 @@ app = marimo.App(app_title="My Title")
 
 @app.cell(hide_code=True)
 def _(mo):
-    mo.md(
-        r"""
-        # SQL notebook
-        """
-    )
+    mo.md(r"""# SQL notebook""")
     return
 
 

tests/_convert/snapshots/unsafe-app.py.txt

@@ -52,12 +52,12 @@ def _(mo):
 def _(mo):
     mo.md(
         r"""
-        Nested fence
-        ````text
-        The guards are
-        ```python {.marimo}
-        ````
-        """
+    Nested fence
+    ````text
+    The guards are
+    ```python {.marimo}
+    ````
+    """
     )
     return
 

tests/_convert/snapshots/unsafe-doc-old.md.txt

@@ -17,10 +17,10 @@ print("Hello, World!")
 ````python {.marimo hide_code="true"}
 mo.md(
     r"""
-    -->
+-->
 
-    ```marimo run convert document.md```
-    """
+```marimo run convert document.md```
+"""
 )
 ````
 
@@ -31,12 +31,12 @@ it's an unparsable cell
 ````python {.marimo hide_code="true"}
 mo.md(
     r"""
-    <!-- Actually markdown -->
-    ```{python} `
-      print("Hello, World!")
+<!-- Actually markdown -->
+```{python} `
+  print("Hello, World!")
 
-    <!-- Disabled code block -->
-    """
+<!-- Disabled code block -->
+"""
 )
 ````