Add xtask for finding crates with missing licenses (#11776)

This PR adds a new `cargo xtask licenses` command for finding crates
with missing license files.

A number of crates were uncovered that were missing a license file, and
have had the appropriate license file added.

Release Notes:

- N/A

tooling/xtask/src/tasks/clippy.rs

@@ -0,0 +1,63 @@
+use std::process::Command;
+
+use anyhow::{bail, Context, Result};
+use clap::Parser;
+
+#[derive(Parser)]
+pub struct ClippyArgs {
+    /// Automatically apply lint suggestions (`clippy --fix`).
+    #[arg(long)]
+    fix: bool,
+
+    /// The package to run Clippy against (`cargo -p <PACKAGE> clippy`).
+    #[arg(long, short)]
+    package: Option<String>,
+}
+
+pub fn run_clippy(args: ClippyArgs) -> Result<()> {
+    let cargo = std::env::var("CARGO").unwrap_or_else(|_| "cargo".to_string());
+
+    let mut clippy_command = Command::new(&cargo);
+    clippy_command.arg("clippy");
+
+    if let Some(package) = args.package.as_ref() {
+        clippy_command.args(["--package", package]);
+    } else {
+        clippy_command.arg("--workspace");
+    }
+
+    clippy_command
+        .arg("--release")
+        .arg("--all-targets")
+        .arg("--all-features");
+
+    if args.fix {
+        clippy_command.arg("--fix");
+    }
+
+    clippy_command.arg("--");
+
+    // Deny all warnings.
+    clippy_command.args(["--deny", "warnings"]);
+
+    eprintln!(
+        "running: {cargo} {}",
+        clippy_command
+            .get_args()
+            .map(|arg| arg.to_str().unwrap())
+            .collect::<Vec<_>>()
+            .join(" ")
+    );
+
+    let exit_status = clippy_command
+        .spawn()
+        .context("failed to spawn child process")?
+        .wait()
+        .context("failed to wait for child process")?;
+
+    if !exit_status.success() {
+        bail!("clippy failed: {}", exit_status);
+    }
+
+    Ok(())
+}

tooling/xtask/src/tasks/licenses.rs

@@ -0,0 +1,39 @@
+use std::path::{Path, PathBuf};
+
+use anyhow::Result;
+use clap::Parser;
+
+use crate::workspace::load_workspace;
+
+#[derive(Parser)]
+pub struct LicensesArgs {}
+
+pub fn run_licenses(_args: LicensesArgs) -> Result<()> {
+    let workspace = load_workspace()?;
+
+    for member in workspace.members {
+        let crate_dir = PathBuf::from(&member);
+
+        if has_any_license_file(
+            &crate_dir,
+            &["LICENSE-APACHE", "LICENSE-GPL", "LICENSE-AGPL"],
+        ) {
+            continue;
+        }
+
+        println!("Missing license: {member}");
+    }
+
+    Ok(())
+}
+
+fn has_any_license_file(path: &Path, license_files: &[&str]) -> bool {
+    for license_file in license_files {
+        let path_to_license = path.join(license_file);
+        if path_to_license.exists() {
+            return true;
+        }
+    }
+
+    false
+}