Generate JSON schema for Ruff options (#1329)

ruff_dev/src/generate_json_schema.rs

@@ -0,0 +1,30 @@
+use std::fs;
+use std::path::PathBuf;
+
+use anyhow::Result;
+use clap::Args;
+use ruff::settings::options::Options;
+use schemars::schema_for;
+
+#[derive(Args)]
+pub struct Cli {
+    /// Write the generated table to stdout (rather than to `ruff.schema.json`).
+    #[arg(long)]
+    dry_run: bool,
+}
+
+pub fn main(cli: &Cli) -> Result<()> {
+    let schema = schema_for!(Options);
+    let schema_string = serde_json::to_string_pretty(&schema).unwrap();
+
+    if cli.dry_run {
+        println!("{schema_string}");
+    } else {
+        let file = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .parent()
+            .expect("Failed to find root directory")
+            .join("ruff.schema.json");
+        fs::write(file, schema_string.as_bytes())?;
+    }
+    Ok(())
+}