flake8_to_ruff: support `isort` options (#2082)

See: https://github.com/charliermarsh/ruff/issues/1749.

flake8_to_ruff/src/main.rs

@@ -18,7 +18,7 @@ use std::path::PathBuf;
 use anyhow::Result;
 use clap::Parser;
 use configparser::ini::Ini;
-use ruff::flake8_to_ruff;
+use ruff::flake8_to_ruff::{self, ExternalConfig};
 
 #[derive(Parser)]
 #[command(
@@ -48,14 +48,18 @@ fn main() -> Result<()> {
     let config = ini.load(cli.file).map_err(|msg| anyhow::anyhow!(msg))?;
 
     // Read the pyproject.toml file.
-    let black = cli
-        .pyproject
-        .map(flake8_to_ruff::parse_black_options)
-        .transpose()?
-        .flatten();
+    let pyproject = cli.pyproject.map(flake8_to_ruff::parse).transpose()?;
+    let external_config = pyproject
+        .as_ref()
+        .and_then(|pyproject| pyproject.tool.as_ref())
+        .map(|tool| ExternalConfig {
+            black: tool.black.as_ref(),
+            isort: tool.isort.as_ref(),
+        })
+        .unwrap_or_default();
 
     // Create Ruff's pyproject.toml section.
-    let pyproject = flake8_to_ruff::convert(&config, black.as_ref(), cli.plugin)?;
+    let pyproject = flake8_to_ruff::convert(&config, &external_config, cli.plugin)?;
     println!("{}", toml_edit::easy::to_string_pretty(&pyproject)?);
 
     Ok(())

src/flake8_to_ruff/black.rs

@@ -1,8 +1,5 @@
 //! Extract Black configuration settings from a pyproject.toml.
 
-use std::path::Path;
-
-use anyhow::Result;
 use serde::{Deserialize, Serialize};
 
 use crate::settings::types::PythonVersion;
@@ -14,20 +11,3 @@ pub struct Black {
     #[serde(alias = "target-version", alias = "target_version")]
     pub target_version: Option<Vec<PythonVersion>>,
 }
-
-#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
-struct Tools {
-    black: Option<Black>,
-}
-
-#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
-struct Pyproject {
-    tool: Option<Tools>,
-}
-
-pub fn parse_black_options<P: AsRef<Path>>(path: P) -> Result<Option<Black>> {
-    let contents = std::fs::read_to_string(path)?;
-    Ok(toml_edit::easy::from_str::<Pyproject>(&contents)?
-        .tool
-        .and_then(|tool| tool.black))
-}

src/flake8_to_ruff/converter.rs

@@ -3,7 +3,7 @@ use std::collections::{BTreeSet, HashMap};
 use anyhow::Result;
 use colored::Colorize;
 
-use super::black::Black;
+use super::external_config::ExternalConfig;
 use super::plugin::Plugin;
 use super::{parser, plugin};
 use crate::registry::RuleSelector;
@@ -23,7 +23,7 @@ use crate::warn_user;
 
 pub fn convert(
     config: &HashMap<String, HashMap<String, Option<String>>>,
-    black: Option<&Black>,
+    external_config: &ExternalConfig,
     plugins: Option<Vec<Plugin>>,
 ) -> Result<Pyproject> {
     // Extract the Flake8 section.
@@ -377,7 +377,7 @@ pub fn convert(
     }
 
     // Extract any settings from the existing `pyproject.toml`.
-    if let Some(black) = black {
+    if let Some(black) = &external_config.black {
         if let Some(line_length) = &black.line_length {
             options.line_length = Some(*line_length);
         }
@@ -389,6 +389,19 @@ pub fn convert(
         }
     }
 
+    if let Some(isort) = &external_config.isort {
+        if let Some(src_paths) = &isort.src_paths {
+            match options.src.as_mut() {
+                Some(src) => {
+                    src.extend(src_paths.clone());
+                }
+                None => {
+                    options.src = Some(src_paths.clone());
+                }
+            }
+        }
+    }
+
     // Create the pyproject.toml.
     Ok(Pyproject::new(options))
 }
@@ -401,6 +414,7 @@ mod tests {
 
     use super::super::plugin::Plugin;
     use super::convert;
+    use crate::flake8_to_ruff::ExternalConfig;
     use crate::registry::RuleSelector;
     use crate::rules::pydocstyle::settings::Convention;
     use crate::rules::{flake8_quotes, pydocstyle};
@@ -411,7 +425,7 @@ mod tests {
     fn it_converts_empty() -> Result<()> {
         let actual = convert(
             &HashMap::from([("flake8".to_string(), HashMap::default())]),
-            None,
+            &ExternalConfig::default(),
             None,
         )?;
         let expected = Pyproject::new(Options {
@@ -475,7 +489,7 @@ mod tests {
                 "flake8".to_string(),
                 HashMap::from([("max-line-length".to_string(), Some("100".to_string()))]),
             )]),
-            None,
+            &ExternalConfig::default(),
             Some(vec![]),
         )?;
         let expected = Pyproject::new(Options {
@@ -539,7 +553,7 @@ mod tests {
                 "flake8".to_string(),
                 HashMap::from([("max_line_length".to_string(), Some("100".to_string()))]),
             )]),
-            None,
+            &ExternalConfig::default(),
             Some(vec![]),
         )?;
         let expected = Pyproject::new(Options {
@@ -603,7 +617,7 @@ mod tests {
                 "flake8".to_string(),
                 HashMap::from([("max_line_length".to_string(), Some("abc".to_string()))]),
             )]),
-            None,
+            &ExternalConfig::default(),
             Some(vec![]),
         )?;
         let expected = Pyproject::new(Options {
@@ -667,7 +681,7 @@ mod tests {
                 "flake8".to_string(),
                 HashMap::from([("inline-quotes".to_string(), Some("single".to_string()))]),
             )]),
-            None,
+            &ExternalConfig::default(),
             Some(vec![]),
         )?;
         let expected = Pyproject::new(Options {
@@ -739,7 +753,7 @@ mod tests {
                     Some("numpy".to_string()),
                 )]),
             )]),
-            None,
+            &ExternalConfig::default(),
             Some(vec![Plugin::Flake8Docstrings]),
         )?;
         let expected = Pyproject::new(Options {
@@ -810,7 +824,7 @@ mod tests {
                 "flake8".to_string(),
                 HashMap::from([("inline-quotes".to_string(), Some("single".to_string()))]),
             )]),
-            None,
+            &ExternalConfig::default(),
             None,
         )?;
         let expected = Pyproject::new(Options {

src/flake8_to_ruff/external_config.rs

@@ -0,0 +1,8 @@
+use super::black::Black;
+use super::isort::Isort;
+
+#[derive(Default)]
+pub struct ExternalConfig<'a> {
+    pub black: Option<&'a Black>,
+    pub isort: Option<&'a Isort>,
+}

src/flake8_to_ruff/isort.rs

@@ -0,0 +1,10 @@
+//! Extract isort configuration settings from a pyproject.toml.
+
+use serde::{Deserialize, Serialize};
+
+/// The [isort configuration](https://pycqa.github.io/isort/docs/configuration/config_files.html).
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Default)]
+pub struct Isort {
+    #[serde(alias = "src-paths", alias = "src_paths")]
+    pub src_paths: Option<Vec<String>>,
+}

src/flake8_to_ruff/mod.rs

@@ -1,8 +1,12 @@
 mod black;
 mod converter;
+mod external_config;
+mod isort;
 mod parser;
 mod plugin;
+mod pyproject;
 
-pub use black::parse_black_options;
 pub use converter::convert;
+pub use external_config::ExternalConfig;
 pub use plugin::Plugin;
+pub use pyproject::parse;

src/flake8_to_ruff/pyproject.rs

@@ -0,0 +1,24 @@
+use std::path::Path;
+
+use anyhow::Result;
+use serde::{Deserialize, Serialize};
+
+use super::black::Black;
+use super::isort::Isort;
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Tools {
+    pub black: Option<Black>,
+    pub isort: Option<Isort>,
+}
+
+#[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Pyproject {
+    pub tool: Option<Tools>,
+}
+
+pub fn parse<P: AsRef<Path>>(path: P) -> Result<Pyproject> {
+    let contents = std::fs::read_to_string(path)?;
+    let pyproject = toml_edit::easy::from_str::<Pyproject>(&contents)?;
+    Ok(pyproject)
+}