Return syntax error

Author: Peter554

rust/src/errors.rs

@@ -1,6 +1,7 @@
-use crate::exceptions::{InvalidModuleExpression, ModuleNotPresent, NoSuchContainer};
+use crate::exceptions::{InvalidModuleExpression, ModuleNotPresent, NoSuchContainer, ParseError};
 use pyo3::exceptions::PyValueError;
 use pyo3::PyErr;
+use ruff_python_parser::ParseError as RuffParseError;
 use thiserror::Error;
 
 #[derive(Debug, Error)]
@@ -16,6 +17,14 @@ pub enum GrimpError {
 
     #[error("{0} is not a valid module expression.")]
     InvalidModuleExpression(String),
+
+    #[error("Error parsing python code (line {line_number}, text {text}).")]
+    ParseError {
+        line_number: usize,
+        text: String,
+        #[source]
+        parse_error: RuffParseError,
+    },
 }
 
 pub type GrimpResult<T> = Result<T, GrimpError>;
@@ -30,6 +39,7 @@ impl From<GrimpError> for PyErr {
             GrimpError::InvalidModuleExpression(_) => {
                 InvalidModuleExpression::new_err(value.to_string())
             }
+            GrimpError::ParseError { .. } => ParseError::new_err(value.to_string()),
         }
     }
 }

rust/src/exceptions.rs

@@ -7,3 +7,4 @@ create_exception!(
     InvalidModuleExpression,
     pyo3::exceptions::PyException
 );
+create_exception!(_rustgrimp, ParseError, pyo3::exceptions::PyException);

rust/src/import_parsing.rs

@@ -1,4 +1,4 @@
-use crate::errors::GrimpResult;
+use crate::errors::{GrimpError, GrimpResult};
 use ruff_python_ast::statement_visitor::{walk_body, walk_stmt, StatementVisitor};
 use ruff_python_ast::{Expr, Stmt};
 use ruff_python_parser::parse_module;
@@ -73,11 +73,22 @@ pub fn parse_imports_from_code(code: &str) -> GrimpResult<Vec<ImportedObject>> {
 fn parse_imports_from_code_without_line_contents(
     code: &str,
 ) -> GrimpResult<Vec<ImportedObjectWithoutLineContents>> {
-    let ast = parse_module(code).expect("failed to parse python code");
-
     let line_index = LineIndex::from_source_text(code);
     let source_code = SourceCode::new(code, &line_index);
 
+    let ast = match parse_module(code) {
+        Ok(ast) => ast,
+        Err(e) => {
+            let line_number = source_code.line_index(e.location.start()).get();
+            let text = source_code.slice(e.location);
+            Err(GrimpError::ParseError {
+                line_number,
+                text: text.to_owned(),
+                parse_error: e,
+            })?
+        }
+    };
+
     let mut visitor = Visitor::new(source_code);
     walk_body(&mut visitor, &ast.syntax().body);
 

rust/src/lib.rs

@@ -5,7 +5,7 @@ pub mod import_parsing;
 pub mod module_expressions;
 
 use crate::errors::{GrimpError, GrimpResult};
-use crate::exceptions::{InvalidModuleExpression, ModuleNotPresent, NoSuchContainer};
+use crate::exceptions::{InvalidModuleExpression, ModuleNotPresent, NoSuchContainer, ParseError};
 use crate::graph::higher_order_queries::Level;
 use crate::graph::{Graph, Module, ModuleIterator, ModuleTokenIterator};
 use crate::module_expressions::ModuleExpression;
@@ -29,6 +29,7 @@ fn _rustgrimp(py: Python<'_>, m: &Bound<'_, PyModule>) -> PyResult<()> {
         "InvalidModuleExpression",
         py.get_type::<InvalidModuleExpression>(),
     )?;
+    m.add("ParseError", py.get_type::<ParseError>())?;
     Ok(())
 }
 

src/grimp/adaptors/importscanner.py

@@ -50,7 +50,9 @@ def scan_for_imports(
 
         try:
             imported_objects = self._get_raw_imported_objects(module_contents)
-        except SyntaxError as e:
+        except rust.ParseError as e:
+            # TODO What to do with the rust.ParseError?
+            # TODO The line number and text are part of str(e), but is there a nice way to get them?
             raise exceptions.SourceSyntaxError(
                 filename=module_filename,
                 lineno=e.lineno,