From fa03adb718db050b51d996d1afc6cbc066c456f5 Mon Sep 17 00:00:00 2001
From: Pratyoy Mukhopadhyay <35388175+pmmukh@users.noreply.github.com>
Date: Tue, 2 Nov 2021 12:00:37 -0700
Subject: [PATCH] [VAULT-4034] Revert back to caching nil values (#13013)

* Revert "[VAULT-4034] Only cache non-nil values (#12993)"

This reverts commit 67e1ed06c7199856f8493f416df55f06603881c6.

* Update sdk/physical/cache.go

Co-authored-by: Nick Cabatoff <ncabatoff@hashicorp.com>

Co-authored-by: Nick Cabatoff <ncabatoff@hashicorp.com>
---
 changelog/12993.txt              |  3 ---
 sdk/physical/cache.go            |  6 ++---
 sdk/physical/inmem/cache_test.go | 42 --------------------------------
 3 files changed, 2 insertions(+), 49 deletions(-)
 delete mode 100644 changelog/12993.txt

diff --git a/changelog/12993.txt b/changelog/12993.txt
deleted file mode 100644
index 5e9068b7cf..0000000000
--- a/changelog/12993.txt
+++ /dev/null
@@ -1,3 +0,0 @@
-```release-note:bug
-sdk/physical: Fix to only populate cache with non-nil values
-```
\ No newline at end of file
diff --git a/sdk/physical/cache.go b/sdk/physical/cache.go
index d399cdae3c..ffac33189b 100644
--- a/sdk/physical/cache.go
+++ b/sdk/physical/cache.go
@@ -184,10 +184,8 @@ func (c *Cache) Get(ctx context.Context, key string) (*Entry, error) {
 		return nil, err
 	}
 
-	if ent != nil {
-		// Cache the result
-		c.lru.Add(key, ent)
-	}
+	// Cache the result, even if nil
+	c.lru.Add(key, ent)
 
 	return ent, nil
 }
diff --git a/sdk/physical/inmem/cache_test.go b/sdk/physical/inmem/cache_test.go
index ec1b5bcde0..e6e6dabfe3 100644
--- a/sdk/physical/inmem/cache_test.go
+++ b/sdk/physical/inmem/cache_test.go
@@ -328,45 +328,3 @@ func TestCache_Refresh(t *testing.T) {
 		t.Fatalf("expected value baz, got %s", string(r.Value))
 	}
 }
-
-// TestCache_UpdateFromStorage fetches a nil value from cache, updates
-// the underlying storage and checks the cache value on a subsequent lookup
-func TestCache_UpdateFromStorage(t *testing.T) {
-	logger := logging.NewVaultLogger(log.Debug)
-
-	inm, err := NewInmem(nil, logger)
-	if err != nil {
-		t.Fatal(err)
-	}
-	cache := physical.NewCache(inm, 0, logger, &metrics.BlackholeSink{})
-	cache.SetEnabled(true)
-
-	ent := &physical.Entry{
-		Key:   "foo",
-		Value: []byte("bar"),
-	}
-
-	// Read should return nil
-	out, err := cache.Get(context.Background(), "foo")
-	if err != nil {
-		t.Fatalf("err: %v", err)
-	}
-	if out != nil {
-		t.Fatalf("should not have key")
-	}
-
-	// Add data to the underlying backend
-	inm.Put(context.Background(), ent)
-
-	// Read should return data
-	out, err = cache.Get(context.Background(), "foo")
-	if err != nil {
-		t.Fatalf("err: %v", err)
-	}
-	if out == nil {
-		t.Fatalf("should have key")
-	}
-	if string(out.Value) != "bar" {
-		t.Fatalf("expected value bar, got %s", string(out.Value))
-	}
-}