feat/2: add scopelint fmt --check

README.md

@@ -33,6 +33,9 @@ This command will format:
 - Solidity files using the configuration specified in `foundry.toml`.
 - TOML files using a hardcoded configuration that indents keys and sorts them alphabetically to improve readability.
 
+**Flags:**
+- `--check`: Show changes without modifying files (dry run mode)
+
 ### `scopelint check`
 
 This command ensures that development [best practices](https://book.getfoundry.sh/tutorials/best-practices) are consistently followed by validating that:

src/config.rs

@@ -17,7 +17,11 @@ pub enum Subcommands {
     Check,
     #[clap(about = "Formats Solidity and TOML files in the codebase.")]
     /// Formats Solidity and TOML files in the codebase.
-    Fmt,
+    Fmt {
+        #[clap(long, help = "Show changes without modifying files")]
+        /// Show changes without modifying files.
+        check: bool,
+    },
     #[clap(about = "Generates a specification for the current project from test names.")]
     /// Generates a specification for the current project from test names.
     Spec,

src/fmt/mod.rs

@@ -1,10 +1,99 @@
+use colored::Colorize;
 use std::{error::Error, fs, process};
 
-/// Format the code.
+/// Check formatting without modifying files.
+/// # Errors
+/// Errors if `forge fmt` fails, or if `taplo` fails to format `foundry.toml`.
+fn check_formatting(taplo_opts: taplo::formatter::Options) -> Result<(), Box<dyn Error>> {
+    println!("Checking formatting...");
+
+    let forge_status = process::Command::new("forge").args(["fmt", "--check"]).output()?;
+
+    let mut has_changes = false;
+
+    // Print any warnings/errors from `forge fmt --check`.
+    if !forge_status.stderr.is_empty() {
+        print!("{}", String::from_utf8(forge_status.stderr)?);
+    }
+
+    // Print the diff output from forge fmt --check with colors
+    if !forge_status.stdout.is_empty() {
+        println!("Solidity files that would be reformatted:");
+        let forge_output = String::from_utf8(forge_status.stdout)?;
+
+        for line in forge_output.lines() {
+            if line.starts_with("Diff in ") {
+                println!("{line}");
+            } else if line.contains("|-") {
+                // Red for removed lines
+                let parts: Vec<&str> = line.split("|-").collect();
+                if parts.len() == 2 {
+                    println!("{}{}{}", parts[0], "|-".red(), parts[1].red());
+                } else {
+                    println!("{line}");
+                }
+            } else if line.contains("|+") {
+                // Green for added lines
+                let parts: Vec<&str> = line.split("|+").collect();
+                if parts.len() == 2 {
+                    println!("{}{}{}", parts[0], "|+".green(), parts[1].green());
+                } else {
+                    println!("{line}");
+                }
+            } else {
+                println!("{line}");
+            }
+        }
+        has_changes = true;
+    }
+
+    // Check if forge fmt found any issues
+    if !forge_status.status.success() {
+        has_changes = true;
+    }
+
+    // Check foundry.toml formatting
+    let config_orig = fs::read_to_string("./foundry.toml")?;
+    let config_fmt = taplo::formatter::format(&config_orig, taplo_opts);
+
+    if config_orig != config_fmt {
+        println!("foundry.toml would be reformatted:");
+        println!("Diff in foundry.toml:");
+
+        // Simple diff output with colors
+        let orig_lines: Vec<&str> = config_orig.lines().collect();
+        let fmt_lines: Vec<&str> = config_fmt.lines().collect();
+
+        for (i, line) in fmt_lines.iter().enumerate() {
+            if i < orig_lines.len() && orig_lines[i] != *line {
+                // Red for removed lines
+                println!("{}    |{}{}", i + 1, "-".red(), orig_lines[i].red());
+                // Green for added lines
+                println!("{}    |{}{}", i + 1, "+".green(), line.green());
+            } else if i >= orig_lines.len() {
+                // Green for new lines
+                println!("{}    |{}{}", i + 1, "+".green(), line.green());
+            }
+        }
+
+        has_changes = true;
+    }
+
+    // Exit with error code if any files would be changed
+    if has_changes {
+        println!("\nRun 'scopelint fmt' to apply these changes.");
+        process::exit(1);
+    } else {
+        println!("All files are properly formatted!");
+    }
+
+    Ok(())
+}
+
+/// Apply formatting to files.
 /// # Errors
 /// Errors if `forge fmt` fails, or if `taplo` fails to format `foundry.toml`.
-pub fn run(taplo_opts: taplo::formatter::Options) -> Result<(), Box<dyn Error>> {
-    // Format Solidity with forge
+fn apply_formatting(taplo_opts: taplo::formatter::Options) -> Result<(), Box<dyn Error>> {
     let forge_status = process::Command::new("forge").arg("fmt").output()?;
 
     // Print any warnings/errors from `forge fmt`.
@@ -18,3 +107,14 @@ pub fn run(taplo_opts: taplo::formatter::Options) -> Result<(), Box<dyn Error>>
     fs::write("./foundry.toml", config_fmt)?;
     Ok(())
 }
+
+/// Format the code.
+/// # Errors
+/// Errors if `forge fmt` fails, or if `taplo` fails to format `foundry.toml`.
+pub fn run(taplo_opts: taplo::formatter::Options, check: bool) -> Result<(), Box<dyn Error>> {
+    if check {
+        check_formatting(taplo_opts)
+    } else {
+        apply_formatting(taplo_opts)
+    }
+}

src/lib.rs

@@ -33,9 +33,9 @@ pub fn run(opts: &config::Opts) -> Result<(), Box<dyn Error>> {
     };
 
     // Execute commands.
-    match opts.subcommand {
+    match &opts.subcommand {
         config::Subcommands::Check => check::run(taplo_opts),
-        config::Subcommands::Fmt => fmt::run(taplo_opts),
+        config::Subcommands::Fmt { check } => fmt::run(taplo_opts, *check),
         config::Subcommands::Spec => spec::run(),
     }
 }