Reenable errcheck linter and fix violations

.golangci.yaml

@@ -194,8 +194,8 @@ linters:
   disable-all: true
   enable:
     - mirror
-    # - errcheck # reenable after https://github.com/open-policy-agent/opa-envoy-plugin/issues/723 is complete
     - govet
+    - errcheck
     - ineffassign
     - intrange
     - revive

envoyauth/evaluation.go

@@ -48,7 +48,9 @@ func Eval(ctx context.Context, evalContext EvalContext, input ast.Value, result
 			logger.WithFields(map[string]any{"err": err}).Error("Unable to start new storage transaction.")
 			return err
 		}
-		defer txnClose(ctx, err)
+		defer func() {
+			_ = txnClose(ctx, err)
+		}()
 		result.Txn = txn
 	}
 
@@ -115,7 +117,8 @@ func Eval(ctx context.Context, evalContext EvalContext, input ast.Value, result
 
 	result.NDBuiltinCache = ndbCache
 	result.Decision = rs[0].Expressions[0].Value
-	return nil
+
+	return err
 }
 
 type hook struct {

envoyauth/evaluation_test.go

@@ -87,7 +87,10 @@ func TestEval(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	defer txnClose(ctx, err)
+	defer func() {
+		_ = txnClose(ctx, err)
+	}()
+
 	er.Txn = txn
 
 	err = Eval(ctx, server, inputValue, er)
@@ -123,8 +126,12 @@ func testAuthzServer(logger logging.Logger) (*mockExtAuthzGrpcServer, error) {
 	ctx := context.Background()
 	store := inmem.New()
 	txn := storage.NewTransactionOrDie(ctx, store, storage.WriteParams)
-	store.UpsertPolicy(ctx, txn, "example.rego", []byte(module))
-	store.Commit(ctx, txn)
+	if err := store.UpsertPolicy(ctx, txn, "example.rego", []byte(module)); err != nil {
+		return nil, err
+	}
+	if err := store.Commit(ctx, txn); err != nil {
+		return nil, err
+	}
 
 	m, err := plugins.New([]byte{}, "test", store,
 		plugins.EnablePrintStatements(true),

internal/internal_test.go

@@ -2361,8 +2361,12 @@ func getPluginManager(module string, customPluginFuncs ...customPluginFunc) (*pl
 	ctx := context.Background()
 	store := inmem.New()
 	txn := storage.NewTransactionOrDie(ctx, store, storage.WriteParams)
-	store.UpsertPolicy(ctx, txn, "example.rego", []byte(module))
-	store.Commit(ctx, txn)
+	if err := store.UpsertPolicy(ctx, txn, "example.rego", []byte(module)); err != nil {
+		return nil, err
+	}
+	if err := store.Commit(ctx, txn); err != nil {
+		return nil, err
+	}
 
 	registry := prometheus.NewRegistry()
 	m, err := plugins.New([]byte{}, "test", store, plugins.WithPrometheusRegister(registry))

test/e2e/testing.go

@@ -39,8 +39,14 @@ func TestAuthzServerWithWithOpts(module string, path string, addr string, opts .
 	ctx := context.Background()
 	store := inmem.New()
 	txn := storage.NewTransactionOrDie(ctx, store, storage.WriteParams)
-	store.UpsertPolicy(ctx, txn, "example.rego", []byte(module))
-	store.Commit(ctx, txn)
+	if err := store.UpsertPolicy(ctx, txn, "example.rego", []byte(module)); err != nil {
+		return nil, err
+	}
+
+	if err := store.Commit(ctx, txn); err != nil {
+		return nil, err
+	}
+
 	m, err := plugins.New([]byte{}, "test", store, opts...)
 	if err != nil {
 		return nil, err