Revalidate but do not update cache when readonly

Shopify · Jan 30, 2024 · 4ea8870 · 4ea8870
1 parent cb3e5b9
commit 4ea8870
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Showing 2 changed files with 40 additions and 13 deletions.
diff --git a/ext/bootsnap/bootsnap.c b/ext/bootsnap/bootsnap.c
@@ -780,10 +780,12 @@ bs_fetch(char * path, VALUE path_v, char * cache_path, VALUE handler, VALUE args
         goto fail_errno;
       }
       valid_cache = cache_key_equal_slow_path(&current_key, &cached_key, input_data);
-      if (valid_cache) { // TODO: readonly
-        if (update_cache_key(&current_key, cache_fd, &errno_provenance)) {
-            exception_message = path_v;
-            goto fail_errno;
+      if (valid_cache) {
+        if (!readonly) {
+          if (update_cache_key(&current_key, cache_fd, &errno_provenance)) {
+              exception_message = path_v;
+              goto fail_errno;
+          }
         }
         bs_instrumentation(sym_revalidated, path_v);
       }
@@ -902,6 +904,10 @@ bs_fetch(char * path, VALUE path_v, char * cache_path, VALUE handler, VALUE args
 static VALUE
 bs_precompile(char * path, VALUE path_v, char * cache_path, VALUE handler)
 {
+  if (readonly) {
+    return Qfalse;
+  }
+
   struct bs_cache_key cached_key, current_key;
   int cache_fd = -1, current_fd = -1;
   int res, valid_cache = 0, exception_tag = 0;
@@ -936,7 +942,7 @@ bs_precompile(char * path, VALUE path_v, char * cache_path, VALUE handler)
         goto fail;
       }
       valid_cache = cache_key_equal_slow_path(&current_key, &cached_key, input_data);
-       if (valid_cache) { // TODO: readonly */
+       if (valid_cache) {
          if (update_cache_key(&current_key, cache_fd, &errno_provenance)) {
              goto fail;
          }

diff --git a/test/compile_cache_test.rb b/test/compile_cache_test.rb
@@ -9,6 +9,7 @@ class CompileCacheTest < Minitest::Test
   def teardown
     super
     Bootsnap::CompileCache::Native.readonly = false
+    Bootsnap.instrumentation = nil
   end
 
   def test_compile_option_crc32
@@ -158,6 +159,34 @@ def test_dont_store_cache_after_a_stale_when_readonly
     load(path)
   end
 
+  def test_dont_revalidate_when_readonly
+    path = Help.set_file("a.rb", "a = a = 3", 100)
+    load(path)
+
+    entries = Dir["#{Bootsnap::CompileCache::ISeq.cache_dir}/**/*"].select { |f| File.file?(f) }
+    assert_equal 1, entries.size
+    cache_entry = entries.first
+    old_cache_content = File.binread(cache_entry)
+
+    Bootsnap::CompileCache::Native.readonly = true
+
+    output = RubyVM::InstructionSequence.compile_file(path)
+    Bootsnap::CompileCache::ISeq.expects(:input_to_storage).never
+    Bootsnap::CompileCache::ISeq.expects(:storage_to_output).once.returns(output)
+    Bootsnap::CompileCache::ISeq.expects(:input_to_output).never
+
+    FileUtils.touch(path, mtime: File.mtime(path) + 50)
+
+    calls = []
+    Bootsnap.instrumentation = ->(event, path) { calls << [event, path] }
+    load(path)
+
+    assert_equal [[:revalidated, "a.rb"]], calls
+
+    new_cache_content = File.binread(cache_entry)
+    assert_equal old_cache_content, new_cache_content, "Cache entry was mutated"
+  end
+
   def test_invalid_cache_file
     path = Help.set_file("a.rb", "a = a = 3", 100)
     cp = Help.cache_path("#{@tmp_dir}-iseq", path)
@@ -177,8 +206,6 @@ def test_instrumentation_hit
     load(file_path)
 
     assert_equal [], calls
-  ensure
-    Bootsnap.instrumentation = nil
   end
 
   def test_instrumentation_miss
@@ -190,8 +217,6 @@ def test_instrumentation_miss
     load(file_path)
 
     assert_equal [[:miss, "a.rb"]], calls
-  ensure
-    Bootsnap.instrumentation = nil
   end
 
   def test_instrumentation_revalidate
@@ -205,8 +230,6 @@ def test_instrumentation_revalidate
     load(file_path)
 
     assert_equal [[:revalidated, "a.rb"]], calls
-  ensure
-    Bootsnap.instrumentation = nil
   end
 
   def test_instrumentation_stale
@@ -220,7 +243,5 @@ def test_instrumentation_stale
     load(file_path)
 
     assert_equal [[:stale, "a.rb"]], calls
-  ensure
-    Bootsnap.instrumentation = nil
   end
 end