uudoc: move tldr.zip warning to build.rs

Move the tldr.zip missing warning from runtime (uudoc.rs) to compile
time (build.rs). This ensures the warning is printed only once during
the build, instead of 100+ times when make calls uudoc separately for
each utility.

Fixes #9940

Author: rynewang

build.rs

@@ -3,7 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-// spell-checker:ignore (vars) krate mangen
+// spell-checker:ignore (vars) krate mangen tldr
 
 use std::env;
 use std::fs::File;
@@ -19,6 +19,18 @@ pub fn main() {
     // See <https://doc.rust-lang.org/cargo/reference/build-scripts.html#change-detection>
     println!("cargo:rerun-if-changed=build.rs");
 
+    // Check for tldr.zip when building uudoc to warn users once at build time
+    // instead of repeatedly at runtime for each utility
+    if env::var("CARGO_FEATURE_UUDOC").is_ok() && !Path::new("docs/tldr.zip").exists() {
+        println!(
+            "cargo:warning=No tldr archive found, so the documentation will not include examples."
+        );
+        println!("cargo:warning=To include examples, download the tldr archive:");
+        println!(
+            "cargo:warning=  curl -L https://github.com/tldr-pages/tldr/releases/latest/download/tldr.zip -o docs/tldr.zip"
+        );
+    }
+
     if let Ok(profile) = env::var("PROFILE") {
         println!("cargo:rustc-cfg=build={profile:?}");
     }

src/bin/uudoc.rs

@@ -133,19 +133,6 @@ fn gen_completions<T: Args>(args: impl Iterator<Item = OsString>, util_map: &Uti
     process::exit(0);
 }
 
-/// print tldr error
-fn print_tldr_error() {
-    eprintln!("Warning: No tldr archive found, so the documentation will not include examples.");
-    eprintln!(
-        "To include examples in the documentation, download the tldr archive and put it in the docs/ folder."
-    );
-    eprintln!();
-    eprintln!(
-        "  curl -L https://github.com/tldr-pages/tldr/releases/latest/download/tldr.zip -o docs/tldr.zip"
-    );
-    eprintln!();
-}
-
 /// # Errors
 /// Returns an error if the writer fails.
 #[allow(clippy::too_many_lines)]
@@ -162,9 +149,6 @@ fn main() -> io::Result<()> {
         match command {
             "manpage" => {
                 let args_iter = args.into_iter().skip(2);
-                if tldr_zip.is_none() {
-                    print_tldr_error();
-                }
                 gen_manpage(
                     &mut tldr_zip,
                     args_iter,
@@ -186,9 +170,6 @@ fn main() -> io::Result<()> {
             }
         }
     }
-    if tldr_zip.is_none() {
-        print_tldr_error();
-    }
     let utils = util_map::<Box<dyn Iterator<Item = OsString>>>();
     match std::fs::create_dir("docs/src/utils/") {
         Err(e) if e.kind() == std::io::ErrorKind::AlreadyExists => Ok(()),

tests/uudoc/mod.rs

@@ -28,9 +28,11 @@ fn test_manpage_generation() {
         "Command failed with status: {}",
         output.status
     );
+    // Note: tldr warning is now printed at build time (in build.rs), not at runtime
     assert!(
-        String::from_utf8_lossy(&output.stderr).contains("Warning: No tldr archive found"),
-        "stderr should contains tldr alert",
+        output.stderr.is_empty(),
+        "stderr should be empty but got: {}",
+        String::from_utf8_lossy(&output.stderr)
     );
 
     let output_str = String::from_utf8_lossy(&output.stdout);
@@ -52,9 +54,11 @@ fn test_manpage_coreutils() {
         "Command failed with status: {}",
         output.status
     );
+    // Note: tldr warning is now printed at build time (in build.rs), not at runtime
     assert!(
-        String::from_utf8_lossy(&output.stderr).contains("Warning: No tldr archive found"),
-        "stderr should contains tldr alert",
+        output.stderr.is_empty(),
+        "stderr should be empty but got: {}",
+        String::from_utf8_lossy(&output.stderr)
     );
 
     let output_str = String::from_utf8_lossy(&output.stdout);
@@ -123,9 +127,11 @@ fn test_manpage_base64() {
         "Command failed with status: {}",
         output.status
     );
+    // Note: tldr warning is now printed at build time (in build.rs), not at runtime
     assert!(
-        String::from_utf8_lossy(&output.stderr).contains("Warning: No tldr archive found"),
-        "stderr should contains tldr alert",
+        output.stderr.is_empty(),
+        "stderr should be empty but got: {}",
+        String::from_utf8_lossy(&output.stderr)
     );
 
     let output_str = String::from_utf8_lossy(&output.stdout);