linux-kernel - [PATCH v2 1/2] rust: replace length checks with match

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Message-Id: <20250529-idiomatic-match-slice-v2-1-4925ca2f1550@gmail.com>
Date: Thu, 29 May 2025 09:14:58 -0400
From: Tamir Duberstein <tamird@...il.com>
To: Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
 Boqun Feng <boqun.feng@...il.com>, Gary Guo <gary@...yguo.net>, 
 Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
 Benno Lossin <lossin@...nel.org>, Andreas Hindborg <a.hindborg@...nel.org>, 
 Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>, 
 Danilo Krummrich <dakr@...nel.org>, 
 Brendan Higgins <brendan.higgins@...ux.dev>, 
 David Gow <davidgow@...gle.com>, Rae Moar <rmoar@...gle.com>
Cc: linux-kselftest@...r.kernel.org, kunit-dev@...glegroups.com, 
 rust-for-linux@...r.kernel.org, linux-kernel@...r.kernel.org, 
 Tamir Duberstein <tamird@...il.com>
Subject: [PATCH v2 1/2] rust: replace length checks with match

Use a match expression with slice patterns instead of length checks and
indexing. The result is more idiomatic, which is a better example for
future Rust code authors.

Reviewed-by: Alice Ryhl <aliceryhl@...gle.com>
Signed-off-by: Tamir Duberstein <tamird@...il.com>
---
 scripts/rustdoc_test_gen.rs | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/scripts/rustdoc_test_gen.rs b/scripts/rustdoc_test_gen.rs
index 1ca253594d38..d796481f4359 100644
--- a/scripts/rustdoc_test_gen.rs
+++ b/scripts/rustdoc_test_gen.rs
@@ -85,24 +85,23 @@ fn find_candidates(
         }
     }
 
-    assert!(
-        valid_paths.len() > 0,
-        "No path candidates found for `{file}`. This is likely a bug in the build system, or some \
-        files went away while compiling."
-    );
-
-    if valid_paths.len() > 1 {
-        eprintln!("Several path candidates found:");
-        for path in valid_paths {
-            eprintln!("    {path:?}");
+    match valid_paths.as_slice() {
+        [] => panic!(
+            "No path candidates found for `{file}`. This is likely a bug in the build system, or \
+            some files went away while compiling."
+        ),
+        [valid_path] => valid_path.to_str().unwrap(),
+        valid_paths => {
+            eprintln!("Several path candidates found:");
+            for path in valid_paths {
+                eprintln!("    {path:?}");
+            }
+            panic!(
+                "Several path candidates found for `{file}`, please resolve the ambiguity by \
+                renaming a file or folder."
+            );
         }
-        panic!(
-            "Several path candidates found for `{file}`, please resolve the ambiguity by renaming \
-            a file or folder."
-        );
     }
-
-    valid_paths[0].to_str().unwrap()
 }
 
 fn main() {

-- 
2.49.0