Optional source map generation (#6894)

crates/ruff_formatter/src/builders.rs

@@ -1,16 +1,17 @@
-use crate::format_element::tag::{Condition, Tag};
-use crate::prelude::tag::{DedentMode, GroupMode, LabelId};
-use crate::prelude::*;
-use crate::{format_element, write, Argument, Arguments, FormatContext, GroupId, TextSize};
-use crate::{Buffer, VecBuffer};
-
-use ruff_text_size::TextRange;
 use std::cell::Cell;
 use std::marker::PhantomData;
 use std::num::NonZeroU8;
+
+use ruff_text_size::TextRange;
 #[allow(clippy::enum_glob_use)]
 use Tag::*;
 
+use crate::format_element::tag::{Condition, Tag};
+use crate::prelude::tag::{DedentMode, GroupMode, LabelId};
+use crate::prelude::*;
+use crate::{format_element, write, Argument, Arguments, FormatContext, GroupId, TextSize};
+use crate::{Buffer, VecBuffer};
+
 /// A line break that only gets printed if the enclosing `Group` doesn't fit on a single line.
 /// It's omitted if the enclosing `Group` fits on a single line.
 /// A soft line break is identical to a hard line break when not enclosed inside of a `Group`.
@@ -283,7 +284,6 @@ impl std::fmt::Debug for StaticText {
 /// ## Examples
 ///
 /// ```
-/// /// ```
 /// use ruff_formatter::format;
 /// use ruff_formatter::prelude::*;
 ///
@@ -329,6 +329,7 @@ pub struct SourcePosition(TextSize);
 impl<Context> Format<Context> for SourcePosition {
     fn fmt(&self, f: &mut Formatter<Context>) -> FormatResult<()> {
         f.write_element(FormatElement::SourcePosition(self.0));
+
         Ok(())
     }
 }

crates/ruff_formatter/src/format_element/document.rs

@@ -1,17 +1,19 @@
-use super::tag::Tag;
+use std::collections::HashMap;
+use std::ops::Deref;
+
+use rustc_hash::FxHashMap;
+
 use crate::format_element::tag::{Condition, DedentMode};
 use crate::prelude::tag::GroupMode;
 use crate::prelude::*;
-use crate::printer::LineEnding;
 use crate::source_code::SourceCode;
 use crate::{format, write, TabWidth};
 use crate::{
     BufferExtensions, Format, FormatContext, FormatElement, FormatOptions, FormatResult, Formatter,
     IndentStyle, LineWidth, PrinterOptions,
 };
-use rustc_hash::FxHashMap;
-use std::collections::HashMap;
-use std::ops::Deref;
+
+use super::tag::Tag;
 
 /// A formatted document.
 #[derive(Debug, Clone, Eq, PartialEq, Default)]
@@ -225,10 +227,9 @@ impl FormatOptions for IrFormatOptions {
 
     fn as_print_options(&self) -> PrinterOptions {
         PrinterOptions {
-            tab_width: TabWidth::default(),
             print_width: self.line_width().into(),
-            line_ending: LineEnding::LineFeed,
             indent_style: IndentStyle::Space(2),
+            ..PrinterOptions::default()
         }
     }
 }
@@ -781,10 +782,11 @@ impl Format<IrFormatContext<'_>> for Condition {
 
 #[cfg(test)]
 mod tests {
+    use ruff_text_size::{TextRange, TextSize};
+
     use crate::prelude::*;
     use crate::{format, format_args, write};
     use crate::{SimpleFormatContext, SourceCode};
-    use ruff_text_size::{TextRange, TextSize};
 
     #[test]
     fn display_elements() {

crates/ruff_formatter/src/lib.rs

@@ -39,7 +39,7 @@ use std::fmt::{Debug, Display};
 use std::marker::PhantomData;
 
 use crate::format_element::document::Document;
-use crate::printer::{Printer, PrinterOptions};
+use crate::printer::{Printer, PrinterOptions, SourceMapGeneration};
 pub use arguments::{Argument, Arguments};
 pub use buffer::{
     Buffer, BufferExtensions, BufferSnapshot, Inspect, RemoveSoftLinesBuffer, VecBuffer,
@@ -311,10 +311,12 @@ impl FormatOptions for SimpleFormatOptions {
     }
 
     fn as_print_options(&self) -> PrinterOptions {
-        PrinterOptions::default()
-            .with_indent(self.indent_style)
-            .with_tab_width(self.tab_width())
-            .with_print_width(self.line_width.into())
+        PrinterOptions {
+            print_width: self.line_width.into(),
+            indent_style: self.indent_style,
+            source_map_generation: SourceMapGeneration::Enabled,
+            ..PrinterOptions::default()
+        }
     }
 }
 

crates/ruff_formatter/src/printer/mod.rs

@@ -396,6 +396,10 @@ impl<'a> Printer<'a> {
     }
 
     fn push_marker(&mut self) {
+        if self.options.source_map_generation.is_disabled() {
+            return;
+        }
+
         let marker = SourceMarker {
             source: self.state.source_position,
             dest: self.state.buffer.text_len(),

crates/ruff_formatter/src/printer/printer_options/mod.rs

@@ -14,39 +14,10 @@ pub struct PrinterOptions {
 
     /// Whether the printer should use tabs or spaces to indent code and if spaces, by how many.
     pub indent_style: IndentStyle,
-}
 
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-pub struct PrintWidth(u32);
-
-impl PrintWidth {
-    pub fn new(width: u32) -> Self {
-        Self(width)
-    }
-}
-
-impl Default for PrintWidth {
-    fn default() -> Self {
-        LineWidth::default().into()
-    }
-}
-
-impl From<LineWidth> for PrintWidth {
-    fn from(width: LineWidth) -> Self {
-        Self(u32::from(u16::from(width)))
-    }
-}
-
-impl From<PrintWidth> for usize {
-    fn from(width: PrintWidth) -> Self {
-        width.0 as usize
-    }
-}
-
-impl From<PrintWidth> for u32 {
-    fn from(width: PrintWidth) -> Self {
-        width.0
-    }
+    /// Whether the printer should build a source map that allows mapping positions in the source document
+    /// to positions in the formatted document.
+    pub source_map_generation: SourceMapGeneration,
 }
 
 impl<'a, O> From<&'a O> for PrinterOptions
@@ -94,6 +65,64 @@ impl PrinterOptions {
     }
 }
 
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct PrintWidth(u32);
+
+impl PrintWidth {
+    pub fn new(width: u32) -> Self {
+        Self(width)
+    }
+}
+
+impl Default for PrintWidth {
+    fn default() -> Self {
+        LineWidth::default().into()
+    }
+}
+
+impl From<LineWidth> for PrintWidth {
+    fn from(width: LineWidth) -> Self {
+        Self(u32::from(u16::from(width)))
+    }
+}
+
+impl From<PrintWidth> for usize {
+    fn from(width: PrintWidth) -> Self {
+        width.0 as usize
+    }
+}
+
+impl From<PrintWidth> for u32 {
+    fn from(width: PrintWidth) -> Self {
+        width.0
+    }
+}
+
+/// Configures whether the formatter and printer generate a source map that allows mapping
+/// positions in the source document to positions in the formatted code.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Default)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+pub enum SourceMapGeneration {
+    /// The formatter generates no source map.
+    #[default]
+    Disabled,
+
+    /// The formatter generates a source map that allows mapping positions in the source document
+    /// to positions in the formatted document. The ability to map positions is useful for range formatting
+    /// or when trying to identify where to move the cursor so that it matches its position in the source document.
+    Enabled,
+}
+
+impl SourceMapGeneration {
+    pub const fn is_enabled(self) -> bool {
+        matches!(self, SourceMapGeneration::Enabled)
+    }
+
+    pub const fn is_disabled(self) -> bool {
+        matches!(self, SourceMapGeneration::Disabled)
+    }
+}
+
 #[allow(dead_code)]
 #[derive(Clone, Debug, Eq, PartialEq, Default)]
 pub enum LineEnding {

crates/ruff_python_formatter/src/lib.rs

@@ -1,11 +1,8 @@
 use thiserror::Error;
 
 use ruff_formatter::format_element::tag;
-use ruff_formatter::prelude::{source_position, text, Formatter, Tag};
-use ruff_formatter::{
-    format, write, Buffer, Format, FormatElement, FormatError, FormatResult, PrintError,
-};
-use ruff_formatter::{Formatted, Printed, SourceCode};
+use ruff_formatter::prelude::*;
+use ruff_formatter::{format, FormatError, Formatted, PrintError, Printed, SourceCode};
 use ruff_python_ast::node::{AnyNodeRef, AstNode};
 use ruff_python_ast::Mod;
 use ruff_python_index::{CommentRanges, CommentRangesBuilder};
@@ -54,23 +51,22 @@ where
         if self.is_suppressed(node_comments.trailing, f.context()) {
             suppressed_node(node.as_any_node_ref()).fmt(f)
         } else {
-            write!(
-                f,
-                [
-                    leading_comments(node_comments.leading),
-                    source_position(node.start())
-                ]
-            )?;
+            leading_comments(node_comments.leading).fmt(f)?;
+
+            let is_source_map_enabled = f.options().source_map_generation().is_enabled();
+
+            if is_source_map_enabled {
+                source_position(node.start()).fmt(f)?;
+            }
+
             self.fmt_fields(node, f)?;
             self.fmt_dangling_comments(node_comments.dangling, f)?;
 
-            write!(
-                f,
-                [
-                    source_position(node.end()),
-                    trailing_comments(node_comments.trailing)
-                ]
-            )
+            if is_source_map_enabled {
+                source_position(node.end()).fmt(f)?;
+            }
+
+            trailing_comments(node_comments.trailing).fmt(f)
         }
     }
 

crates/ruff_python_formatter/src/options.rs

@@ -1,4 +1,4 @@
-use ruff_formatter::printer::{LineEnding, PrinterOptions};
+use ruff_formatter::printer::{LineEnding, PrinterOptions, SourceMapGeneration};
 use ruff_formatter::{FormatOptions, IndentStyle, LineWidth, TabWidth};
 use ruff_python_ast::PySourceType;
 use std::path::Path;
@@ -33,6 +33,10 @@ pub struct PyFormatOptions {
 
     /// Whether to expand lists or elements if they have a trailing comma such as `(a, b,)`.
     magic_trailing_comma: MagicTrailingComma,
+
+    /// Should the formatter generate a source map that allows mapping source positions to positions
+    /// in the formatted document.
+    source_map_generation: SourceMapGeneration,
 }
 
 fn default_line_width() -> LineWidth {
@@ -56,6 +60,7 @@ impl Default for PyFormatOptions {
             tab_width: default_tab_width(),
             quote_style: QuoteStyle::default(),
             magic_trailing_comma: MagicTrailingComma::default(),
+            source_map_generation: SourceMapGeneration::default(),
         }
     }
 }
@@ -85,6 +90,10 @@ impl PyFormatOptions {
         self.source_type
     }
 
+    pub fn source_map_generation(&self) -> SourceMapGeneration {
+        self.source_map_generation
+    }
+
     #[must_use]
     pub fn with_quote_style(mut self, style: QuoteStyle) -> Self {
         self.quote_style = style;
@@ -129,6 +138,7 @@ impl FormatOptions for PyFormatOptions {
             print_width: self.line_width.into(),
             line_ending: LineEnding::LineFeed,
             indent_style: self.indent_style,
+            source_map_generation: self.source_map_generation,
         }
     }
 }