lints: Factor out walk_configuration() helper

Add a helper function that returns WalkConfiguration with noxdev()
enabled by default. This ensures consistent behavior across all
filesystem walks in the linting code.

The doc comment clarifies that noxdev skips directory mount points
(to avoid descending into bind mounts, tmpfs, etc.) but non-directory
mount points like bind-mounted regular files will still be visited.

Assisted-by: OpenCode (Opus 4.5)
Signed-off-by: Colin Walters <walters@verbum.org>

crates/lib/src/lints.rs

@@ -29,6 +29,16 @@ use serde::Serialize;
 
 use crate::bootc_composefs::boot::EFI_LINUX;
 
+/// Create a default WalkConfiguration with noxdev enabled.
+///
+/// This ensures we skip directory mount points when walking,
+/// which is important to avoid descending into bind mounts, tmpfs, etc.
+/// Note that non-directory mount points (e.g. bind-mounted regular files)
+/// will still be visited.
+fn walk_configuration() -> WalkConfiguration<'static> {
+    WalkConfiguration::default().noxdev()
+}
+
 /// Reference to embedded default baseimage content that should exist.
 const BASEIMAGE_REF: &str = "usr/share/doc/bootc/baseimage/base";
 // https://systemd.io/API_FILE_SYSTEMS/ with /var added for us
@@ -295,9 +305,7 @@ fn lint_inner<'skip>(
     let mut recursive_lints = BTreeSet::from_iter(recursive_lints);
     let mut recursive_errors = BTreeMap::new();
     root.walk(
-        &WalkConfiguration::default()
-            .noxdev()
-            .path_base(Path::new("/")),
+        &walk_configuration().path_base(Path::new("/")),
         |e| -> std::io::Result<_> {
             // If there's no recursive lints, we're done!
             if recursive_lints.is_empty() {
@@ -813,9 +821,7 @@ fn check_runtime_only_dirs(root: &Dir, config: &LintExecutionConfig) -> LintResu
         };
 
         d.walk(
-            &WalkConfiguration::default()
-                .noxdev()
-                .path_base(Path::new(dirname)),
+            &walk_configuration().path_base(Path::new(dirname)),
             |entry| -> std::io::Result<_> {
                 // Skip mount points (bind mounts, tmpfs, etc.) - these are
                 // container-runtime injected content like .containerenv
@@ -1095,9 +1101,7 @@ mod tests {
         // Helper function to execute a recursive lint function over a directory.
         let mut result = lint_ok();
         root.walk(
-            &WalkConfiguration::default()
-                .noxdev()
-                .path_base(Path::new("/")),
+            &walk_configuration().path_base(Path::new("/")),
             |e| -> Result<_> {
                 let r = f(e, config)?;
                 match r {