theme_importer: Format generated themes (#3255)

This PR makes the `theme_importer` format the themes that it generates
automatically.

Release Notes:

- N/A

crates/theme_importer/src/main.rs

@@ -5,6 +5,7 @@ mod vscode;
 use std::fs::{self, File};
 use std::io::Write;
 use std::path::PathBuf;
+use std::process::Command;
 use std::str::FromStr;
 
 use anyhow::{anyhow, Context, Result};
@@ -152,6 +153,9 @@ fn main() -> Result<()> {
 
         let theme_module = format!(
             r#"
+            // This file was generated by the `theme_importer`.
+            // Be careful when modifying it by hand.
+
             use gpui::rgba;
 
             use crate::{{
@@ -174,7 +178,7 @@ fn main() -> Result<()> {
         r#"
         use crate::UserThemeFamily;
 
-        pub(crate) fn all_imported_themes() -> Vec<UserThemeFamily> {{
+        pub(crate) fn all_user_themes() -> Vec<UserThemeFamily> {{
             vec![{all_themes}]
         }}
         "#,
@@ -187,6 +191,9 @@ fn main() -> Result<()> {
 
     let mod_rs_contents = format!(
         r#"
+        // This file was generated by the `theme_importer`.
+        // Be careful when modifying it by hand.
+
         {mod_statements}
 
         {use_statements}
@@ -208,5 +215,23 @@ fn main() -> Result<()> {
 
     mod_rs_file.write_all(mod_rs_contents.as_bytes())?;
 
+    println!("Formatting themes...");
+
+    let format_result = format_themes_crate()
+        // We need to format a second time to catch all of the formatting issues.
+        .and_then(|_| format_themes_crate());
+
+    if let Err(err) = format_result {
+        eprintln!("Failed to format themes: {}", err);
+    }
+
+    println!("Done!");
+
     Ok(())
 }
+
+fn format_themes_crate() -> std::io::Result<std::process::Output> {
+    Command::new("cargo")
+        .args(["fmt", "--package", "theme2"])
+        .output()
+}