Add copyright command.

Cargo.toml

@@ -16,3 +16,4 @@ rust.missing_docs = "warn"
 [workspace.dependencies]
 anyhow = "1.0.100"
 clap = "4.5.56"
+time = "0.3.46"

prep/Cargo.toml

@@ -21,3 +21,4 @@ workspace = true
 [dependencies]
 anyhow.workspace = true
 clap = { workspace = true, features = ["derive"] }
+time.workspace = true

prep/src/cmd/copyright.rs

@@ -0,0 +1,61 @@
+// Copyright 2026 the Prep Authors
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use std::process::Command;
+
+use anyhow::{Context, bail, ensure};
+use time::UtcDateTime;
+
+use crate::ui;
+use crate::ui::style::{ERROR, HEADER, LITERAL, NOTE};
+
+// TODO: Allow configuring the regex
+// TODO: Allow excluding files from the check
+// TODO: ALlow configuring the project name
+// TODO: Allow configuring the license (or fetch it from Cargo.toml per-package?)
+
+const REGEX: &str = r#"^// Copyright (19|20)[\d]{2} (.+ and )?the Prep Authors( and .+)?$\n^// SPDX-License-Identifier: Apache-2\.0 OR MIT$\n\n"#;
+
+/// Verify copyright headers.
+pub fn run() -> anyhow::Result<()> {
+    let mut cmd = Command::new("rg");
+    let cmd = cmd
+        .arg(REGEX)
+        .arg("--files-without-match")
+        .arg("--multiline")
+        .args(["-g", "*.rs"])
+        .arg(".");
+
+    ui::print_cmd(cmd);
+
+    let output = cmd.output().context("failed to run ripgrep")?;
+
+    // ripgrep exits with code 1 in case of no matches, code 2 in case of error
+    ensure!(
+        output.status.success() || output.status.code().is_some_and(|code| code == 1),
+        "ripgrep failed: {}",
+        output.status
+    );
+
+    if !output.stdout.is_empty() {
+        print_missing(String::from_utf8(output.stdout).unwrap());
+        bail!("failed copyright header verification");
+    }
+
+    let h = HEADER;
+    eprintln!("    {h}Verified{h:#} all source files have correct copyright headers.");
+
+    Ok(())
+}
+
+fn print_missing(msg: String) {
+    let (e, l, n) = (ERROR, LITERAL, NOTE);
+    let year = UtcDateTime::now().year();
+
+    eprintln!("{e}The following files lack the correct copyright header:{e:#}");
+    eprintln!("{l}{msg}{l:#}");
+    eprintln!("{n}Please add the following header:{n:#}\n");
+    eprintln!("// Copyright {year} the Prep Authors");
+    eprintln!("// SPDX-License-Identifier: Apache-2.0 OR MIT");
+    eprintln!("\n... rest of the file ...\n");
+}

prep/src/cmd/mod.rs

@@ -5,6 +5,7 @@ use clap::ValueEnum;
 
 pub mod ci;
 pub mod clippy;
+pub mod copyright;
 pub mod format;
 
 /// Cargo targets.

prep/src/main.rs

@@ -35,6 +35,8 @@ enum Commands {
         #[arg(short, long)]
         strict: bool,
     },
+    #[command()]
+    Copyright,
     #[command(alias = "fmt")]
     Format {
         #[arg(short, long)]
@@ -58,6 +60,7 @@ fn main() -> anyhow::Result<()> {
             no_fail_fast,
         } => cmd::ci::run(extended, !no_fail_fast),
         Commands::Clippy { targets, strict } => cmd::clippy::run(targets, strict),
+        Commands::Copyright => cmd::copyright::run(),
         Commands::Format { check } => cmd::format::run(check),
     }
 }

prep/src/ui/help.rs

@@ -4,7 +4,7 @@
 use clap::Command;
 use clap::builder::StyledStr;
 
-use crate::ui;
+use crate::ui::style::{HEADER, LITERAL, PLACEHOLDER};
 
 /// Sets our custom help messages.
 pub fn set(cmd: Command) -> Command {
@@ -18,6 +18,8 @@ pub fn set(cmd: Command) -> Command {
             scmd.override_help(format_msg())
         } else if name == "clippy" {
             scmd.override_help(clippy_msg())
+        } else if name == "copyright" {
+            scmd.override_help(copyright_msg())
         } else {
             panic!("Sub-command '{name}' help message is not implemented");
         }
@@ -26,22 +28,23 @@ pub fn set(cmd: Command) -> Command {
 
 /// Returns the main help message.
 pub fn root_msg() -> StyledStr {
-    let (gb, cb, bb) = ui::styles();
+    let (h, l, p) = (HEADER, LITERAL, PLACEHOLDER);
     let help = format!(
         "\
 Prepare Rust projects for greatness.
 
-{gb}Usage:{gb:#} {cb}prep{cb:#} {bb}[command] [options]{bb:#}
+{h}Usage:{h:#} {l}prep{l:#} {p}[command] [options]{p:#}
 
-{gb}Commands:{gb:#}
-  {cb}     ci              {cb:#}Verify for CI.
-  {cb}clp  clippy          {cb:#}Analyze with Clippy.
-  {cb}fmt  format          {cb:#}Format with rustfmt.
-  {cb}     help            {cb:#}Print help for the provided command.
+{h}Commands:{h:#}
+  {l}     ci              {l:#}Verify for CI.
+  {l}clp  clippy          {l:#}Analyze with Clippy.
+  {l}     copyright       {l:#}Verify copyright headers.
+  {l}fmt  format          {l:#}Format with rustfmt.
+  {l}     help            {l:#}Print help for the provided command.
 
-{gb}Options:{gb:#}
-  {cb}-h   --help          {cb:#}Print help for the provided command.
-  {cb}-V   --version       {cb:#}Print version information.
+{h}Options:{h:#}
+  {l}-h   --help          {l:#}Print help for the provided command.
+  {l}-V   --version       {l:#}Print version information.
 "
     );
 
@@ -50,64 +53,80 @@ Prepare Rust projects for greatness.
 
 /// Returns the `ci` help message.
 fn ci_msg() -> StyledStr {
-    let (gb, cb, bb) = ui::styles();
-
+    let (h, l, p) = (HEADER, LITERAL, PLACEHOLDER);
     let help = format!(
         "\
 Verify the Rust workspace for CI.
 
-{gb}Usage:{gb:#} {cb}prep ci{cb:#} {bb}[options]{bb:#}
+{h}Usage:{h:#} {l}prep ci{l:#} {p}[options]{p:#}
 
-{gb}Options:{gb:#}
-  {cb}-e   --extended      {cb:#}Run the extended verification suite.
-  ····                     ······Good idea for actual CI, rarely useful for local prep.
-  {cb}-n   --no-fail-fast  {cb:#}Keep going when encountering an error.
-  {cb}-h   --help          {cb:#}Print this help message.
+{h}Options:{h:#}
+  {l}-e   --extended      {l:#}Run the extended verification suite.
+  ···                     ·····Good idea for actual CI, rarely useful for local prep.
+  {l}-n   --no-fail-fast  {l:#}Keep going when encountering an error.
+  {l}-h   --help          {l:#}Print this help message.
 "
     )
     .replace("·", "");
 
     StyledStr::from(help)
 }
 
-/// Returns the `format` help message.
-fn format_msg() -> StyledStr {
-    let (gb, cb, bb) = ui::styles();
+/// Returns the `clippy` help message.
+fn clippy_msg() -> StyledStr {
+    let (h, l, p) = (HEADER, LITERAL, PLACEHOLDER);
+    let help = format!(
+        "\
+Analyze the Rust workspace with Clippy.
+
+{h}Usage:{h:#} {l}prep clp{l:#}    {p}[options]{p:#}
+···      ····· {l}prep clippy{l:#} {p}[options]{p:#}
 
+{h}Options:{h:#}
+  {l}-c   --crates <val>  {l:#}Target specified crates. Possible values:
+  ···                     ·····{p}main{p:#} -> Binaries and the main library. (default)
+  ···                     ·····{p}aux{p:#}  -> Examples, tests, and benches.
+  ···                     ·····{p}all{p:#}  -> All of the above.
+  {l}-s   --strict        {l:#}Treat warnings as errors.
+  {l}-h   --help          {l:#}Print this help message.
+"
+    )
+    .replace("·", "");
+
+    StyledStr::from(help)
+}
+
+/// Returns the `copyright` help message.
+fn copyright_msg() -> StyledStr {
+    let (h, l) = (HEADER, LITERAL);
     let help = format!(
         "\
-Format the Rust workspace with rustfmt.
+Verify that all Rust source files have the correct copyright header.
 
-{gb}Usage:{gb:#} {cb}prep fmt{cb:#}    {bb}[options]{bb:#}
-····      ······ {cb}prep format{cb:#} {bb}[options]{bb:#}
+{h}Usage:{h:#} {l}prep copyright{l:#}
 
-{gb}Options:{gb:#}
-  {cb}-c   --check         {cb:#}Verify that the workspace is already formatted.
-  {cb}-h   --help          {cb:#}Print this help message.
+{h}Options:{h:#}
+  {l}-h   --help          {l:#}Print this help message.
 "
     )
     .replace("·", "");
 
     StyledStr::from(help)
 }
 
-/// Returns the `clippy` help message.
-fn clippy_msg() -> StyledStr {
-    let (gb, cb, bb) = ui::styles();
+/// Returns the `format` help message.
+fn format_msg() -> StyledStr {
+    let (h, l, p) = (HEADER, LITERAL, PLACEHOLDER);
     let help = format!(
         "\
-Analyze the Rust workspace with Clippy.
+Format the Rust workspace with rustfmt.
 
-{gb}Usage:{gb:#} {cb}prep clp{cb:#}    {bb}[options]{bb:#}
-····      ······ {cb}prep clippy{cb:#} {bb}[options]{bb:#}
+{h}Usage:{h:#} {l}prep fmt{l:#}    {p}[options]{p:#}
+···      ····· {l}prep format{l:#} {p}[options]{p:#}
 
-{gb}Options:{gb:#}
-  {cb}-c   --crates <val>  {cb:#}Target specified crates. Possible values:
-  ····                     ······{bb}main{bb:#} -> Binaries and the main library. (default)
-  ····                     ······{bb}aux{bb:#}  -> Examples, tests, and benches.
-  ····                     ······{bb}all{bb:#}  -> All of the above.
-  {cb}-s   --strict        {cb:#}Treat warnings as errors.
-  {cb}-h   --help          {cb:#}Print this help message.
+{h}Options:{h:#}
+  {l}-c   --check         {l:#}Verify that the workspace is already formatted.
+  {l}-h   --help          {l:#}Print this help message.
 "
     )
     .replace("·", "");