From fb8c58439ced2f2839ab272d087517c1610c49b0 Mon Sep 17 00:00:00 2001
From: Charlotte Hartmann Paludo <git@charlotteharludo.com>
Date: Fri, 12 Sep 2025 08:14:01 +0200
Subject: [PATCH] fix: do not reuse excluded status from cache

---
 lychee-bin/src/cache.rs       | 61 ++++++++++++++++++++++++++++++++---
 lychee-bin/src/main.rs        |  6 +++-
 lychee-lib/src/types/cache.rs | 23 ++++++++++++-
 3 files changed, 83 insertions(+), 7 deletions(-)

diff --git a/lychee-bin/src/cache.rs b/lychee-bin/src/cache.rs
index 4e872d4567..644526ce81 100644
--- a/lychee-bin/src/cache.rs
+++ b/lychee-bin/src/cache.rs
@@ -1,7 +1,7 @@
 use crate::time::{self, Timestamp, timestamp};
 use anyhow::Result;
 use dashmap::DashMap;
-use lychee_lib::{CacheStatus, Status, Uri};
+use lychee_lib::{CacheStatus, Status, StatusCodeExcluder, Uri};
 use serde::{Deserialize, Serialize};
 use std::path::Path;
 
@@ -33,7 +33,11 @@ pub(crate) trait StoreExt {
     fn store<T: AsRef<Path>>(&self, path: T) -> Result<()>;
 
     /// Load cache from path. Discard entries older than `max_age_secs`
-    fn load<T: AsRef<Path>>(path: T, max_age_secs: u64) -> Result<Cache>;
+    fn load<T: AsRef<Path>>(
+        path: T,
+        max_age_secs: u64,
+        excluder: &StatusCodeExcluder,
+    ) -> Result<Cache>;
 }
 
 impl StoreExt for Cache {
@@ -47,7 +51,11 @@ impl StoreExt for Cache {
         Ok(())
     }
 
-    fn load<T: AsRef<Path>>(path: T, max_age_secs: u64) -> Result<Cache> {
+    fn load<T: AsRef<Path>>(
+        path: T,
+        max_age_secs: u64,
+        excluder: &StatusCodeExcluder,
+    ) -> Result<Cache> {
         let mut rdr = csv::ReaderBuilder::new()
             .has_headers(false)
             .from_path(path)?;
@@ -58,10 +66,53 @@ impl StoreExt for Cache {
             let (uri, value): (Uri, CacheValue) = result?;
             // Discard entries older than `max_age_secs`.
             // This allows gradually updating the cache over multiple runs.
-            if current_ts - value.timestamp < max_age_secs {
-                map.insert(uri, value);
+            if current_ts - value.timestamp >= max_age_secs {
+                continue;
             }
+
+            // Discard entries for status codes which have been excluded.
+            // Without this check, an entry might be cached, then its status code is configured as
+            // excluded, and in subsequent runs the cached value is still reused.
+            if value.status.is_excluded(excluder) {
+                continue;
+            }
+
+            map.insert(uri, value);
         }
         Ok(map)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use dashmap::DashMap;
+    use lychee_lib::{AcceptRange, CacheStatus, StatusCodeExcluder, Uri};
+
+    use crate::{
+        cache::{Cache, CacheValue, StoreExt},
+        time::timestamp,
+    };
+
+    #[test]
+    fn test_excluded_status_not_reused_from_cache() {
+        let uri: Uri = "https://example.com".try_into().unwrap();
+
+        let cache: Cache = DashMap::<Uri, CacheValue>::new();
+        cache.insert(
+            uri.clone(),
+            CacheValue {
+                status: CacheStatus::Ok(429),
+                timestamp: timestamp(),
+            },
+        );
+
+        let tmp = tempfile::NamedTempFile::new().unwrap();
+        cache.store(tmp.path()).unwrap();
+
+        let mut excluder = StatusCodeExcluder::new();
+        excluder.add_range(AcceptRange::new_from(400, 500).unwrap());
+
+        let cache = Cache::load(tmp.path(), u64::MAX, &excluder).unwrap();
+        assert!(cache.get(&uri).is_none());
+    }
+}
diff --git a/lychee-bin/src/main.rs b/lychee-bin/src/main.rs
index c814b0aa7c..1321f0a926 100644
--- a/lychee-bin/src/main.rs
+++ b/lychee-bin/src/main.rs
@@ -246,7 +246,11 @@ fn load_cache(cfg: &Config) -> Option<Cache> {
         }
     }
 
-    let cache = Cache::load(LYCHEE_CACHE_FILE, cfg.max_cache_age.as_secs());
+    let cache = Cache::load(
+        LYCHEE_CACHE_FILE,
+        cfg.max_cache_age.as_secs(),
+        &cfg.cache_exclude_status,
+    );
     match cache {
         Ok(cache) => Some(cache),
         Err(e) => {
diff --git a/lychee-lib/src/types/cache.rs b/lychee-lib/src/types/cache.rs
index aa42a50a9d..41f7f1529e 100644
--- a/lychee-lib/src/types/cache.rs
+++ b/lychee-lib/src/types/cache.rs
@@ -2,7 +2,7 @@ use std::fmt::Display;
 
 use serde::{Deserialize, Deserializer, Serialize};
 
-use crate::{ErrorKind, Status};
+use crate::{ErrorKind, Status, StatusCodeExcluder};
 
 /// Representation of the status of a cached request. This is kept simple on
 /// purpose because the type gets serialized to a cache file and might need to
@@ -89,6 +89,27 @@ impl From<&Status> for CacheStatus {
     }
 }
 
+impl From<CacheStatus> for Option<u16> {
+    fn from(val: CacheStatus) -> Self {
+        match val {
+            CacheStatus::Ok(status) => Some(status),
+            CacheStatus::Error(status) => status,
+            _ => None,
+        }
+    }
+}
+
+impl CacheStatus {
+    /// Returns `true` if the cache status is excluded by the given [`StatusCodeExcluder`].
+    #[must_use]
+    pub fn is_excluded(&self, excluder: &StatusCodeExcluder) -> bool {
+        match Option::<u16>::from(*self) {
+            Some(status) => excluder.contains(status),
+            _ => false,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use serde::Deserialize;