Detect and ignore Jupyter automagics

crates/ruff_notebook/resources/test/fixtures/jupyter/cell/automagic.json

@@ -0,0 +1,8 @@
+{
+  "execution_count": null,
+  "cell_type": "code",
+  "id": "1",
+  "metadata": {},
+  "outputs": [],
+  "source": ["pip install requests"]
+}

crates/ruff_notebook/src/notebook.rs

@@ -80,14 +80,127 @@ impl Cell {
         // Ignore cells containing cell magic as they act on the entire cell
         // as compared to line magic which acts on a single line.
         !match source {
-            SourceValue::String(string) => string
-                .lines()
-                .any(|line| line.trim_start().starts_with("%%")),
+            SourceValue::String(string) => string.lines().any(Self::is_magic_cell),
             SourceValue::StringArray(string_array) => string_array
                 .iter()
-                .any(|line| line.trim_start().starts_with("%%")),
+                .map(String::as_str)
+                .any(Self::is_magic_cell),
         }
     }
+
+    /// Returns `true` if a cell should be ignored due to the use of cell magics.
+    fn is_magic_cell(line: &str) -> bool {
+        let line = line.trim_start();
+
+        // Detect cell magics (which operate on multiple lines).
+        if line.starts_with("%%") {
+            return true;
+        }
+
+        // Detect automatic line magics (automagic), which aren't supported by the parser. If a line
+        // magic uses automagic, Jupyter doesn't allow following it with non-magic lines anyway, so
+        // we aren't missing out on any valid Python code.
+        //
+        // For example, this is valid:
+        // ```jupyter
+        // cat /path/to/file
+        // cat /path/to/file
+        // ```
+        //
+        // But this is invalid:
+        // ```jupyter
+        // cat /path/to/file
+        // x = 1
+        // ```
+        //
+        // See: https://ipython.readthedocs.io/en/stable/interactive/magics.html
+        if line.split_whitespace().next().is_some_and(|token| {
+            matches!(
+                token,
+                "alias"
+                    | "alias_magic"
+                    | "autoawait"
+                    | "autocall"
+                    | "automagic"
+                    | "bookmark"
+                    | "cd"
+                    | "code_wrap"
+                    | "colors"
+                    | "conda"
+                    | "config"
+                    | "debug"
+                    | "dhist"
+                    | "dirs"
+                    | "doctest_mode"
+                    | "edit"
+                    | "env"
+                    | "gui"
+                    | "history"
+                    | "killbgscripts"
+                    | "load"
+                    | "load_ext"
+                    | "loadpy"
+                    | "logoff"
+                    | "logon"
+                    | "logstart"
+                    | "logstate"
+                    | "logstop"
+                    | "lsmagic"
+                    | "macro"
+                    | "magic"
+                    | "mamba"
+                    | "matplotlib"
+                    | "micromamba"
+                    | "notebook"
+                    | "page"
+                    | "pastebin"
+                    | "pdb"
+                    | "pdef"
+                    | "pdoc"
+                    | "pfile"
+                    | "pinfo"
+                    | "pinfo2"
+                    | "pip"
+                    | "popd"
+                    | "pprint"
+                    | "precision"
+                    | "prun"
+                    | "psearch"
+                    | "psource"
+                    | "pushd"
+                    | "pwd"
+                    | "pycat"
+                    | "pylab"
+                    | "quickref"
+                    | "recall"
+                    | "rehashx"
+                    | "reload_ext"
+                    | "rerun"
+                    | "reset"
+                    | "reset_selective"
+                    | "run"
+                    | "save"
+                    | "sc"
+                    | "set_env"
+                    | "sx"
+                    | "system"
+                    | "tb"
+                    | "time"
+                    | "timeit"
+                    | "unalias"
+                    | "unload_ext"
+                    | "who"
+                    | "who_ls"
+                    | "whos"
+                    | "xdel"
+                    | "xmode"
+            )
+        }) {
+            return true;
+        }
+
+        false
+    }
 }
 
 /// An error that can occur while deserializing a Jupyter Notebook.
@@ -481,6 +594,7 @@ mod tests {
     #[test_case(Path::new("code_and_magic.json"), true; "code_and_magic")]
     #[test_case(Path::new("only_code.json"), true; "only_code")]
     #[test_case(Path::new("cell_magic.json"), false; "cell_magic")]
+    #[test_case(Path::new("automagic.json"), false; "automagic")]
     fn test_is_valid_code_cell(path: &Path, expected: bool) -> Result<()> {
         /// Read a Jupyter cell from the `resources/test/fixtures/jupyter/cell` directory.
         fn read_jupyter_cell(path: impl AsRef<Path>) -> Result<Cell> {