fix: Fix reporting of local/remote cache misses in depend mode

3 files changed, 15 insertions, 0 deletions

diff --git a/src/ccache.cpp b/src/ccache.cpp
index c063a58f..8791f788 100644
--- a/src/ccache.cpp
+++ b/src/ccache.cpp
@@ -631,6 +631,11 @@ process_preprocessed_file(Context& ctx, Hash& hash, const std::string& path)
 static std::optional<Digest>
 result_key_from_depfile(Context& ctx, Hash& hash)
 {
+  // Make sure that result hash will always be different from the manifest hash
+  // since there otherwise may a storage key collision (in case the dependency
+  // file is empty).
+  hash.hash_delimiter("result");
+
   const auto file_content =
     util::read_file<std::string>(ctx.args_info.output_dep);
   if (!file_content) {
diff --git a/src/storage/Storage.cpp b/src/storage/Storage.cpp
index 5c843db2..da707ea6 100644
--- a/src/storage/Storage.cpp
+++ b/src/storage/Storage.cpp
@@ -463,6 +463,11 @@ Storage::get_from_remote_storage(const Digest& key,
       local.increment_statistic(core::Statistic::remote_storage_read_miss);
       if (type == core::CacheEntryType::result) {
         local.increment_statistic(core::Statistic::remote_storage_miss);
+      } else if (m_config.depend_mode()) {
+        // With the depend mode enabled, a missing manifest means that we can't
+        // even try to look up a result, so note the miss already now.
+        ASSERT(type == core::CacheEntryType::manifest);
+        local.increment_statistic(core::Statistic::remote_storage_miss);
       }
     }
   }
diff --git a/src/storage/local/LocalStorage.cpp b/src/storage/local/LocalStorage.cpp
index 274a4460..f1984caa 100644
--- a/src/storage/local/LocalStorage.cpp
+++ b/src/storage/local/LocalStorage.cpp
@@ -223,6 +223,11 @@ LocalStorage::get(const Digest& key, const core::CacheEntryType type)
   if (type == core::CacheEntryType::result) {
     increment_statistic(return_value ? core::Statistic::local_storage_hit
                                      : core::Statistic::local_storage_miss);
+  } else if (m_config.depend_mode() && !return_value) {
+    // With the depend mode enabled, a missing manifest means that we can't even
+    // try to look up a result, so note the miss already now.
+    ASSERT(type == core::CacheEntryType::manifest);
+    increment_statistic(core::Statistic::local_storage_miss);
   }
 
   return return_value;