From cba610c245265ff50ea3c56a9961da218ed7d730 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Wed, 11 Nov 2020 15:52:59 -0600
Subject: [PATCH] StatementErrored does not need context nor return an error

---
 stmtcache/lru.go       | 14 ++++----------
 stmtcache/lru_test.go  |  7 +++----
 stmtcache/stmtcache.go | 10 ++++------
 3 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/stmtcache/lru.go b/stmtcache/lru.go
index 2f183f90..f58f2ac3 100644
--- a/stmtcache/lru.go
+++ b/stmtcache/lru.go
@@ -88,24 +88,18 @@ func (c *LRU) Clear(ctx context.Context) error {
 	return nil
 }
 
-func (c *LRU) StatementErrored(ctx context.Context, sql string, err error) error {
+func (c *LRU) StatementErrored(sql string, err error) {
 	pgErr, ok := err.(*pgconn.PgError)
 	if !ok {
-		// we don't know how to handle this error
-		return nil
+		return
 	}
 
 	isInvalidCachedPlanError := pgErr.Severity == "ERROR" &&
 		pgErr.Code == "0A000" &&
 		pgErr.Message == "cached plan must not change result type"
-	if !isInvalidCachedPlanError {
-		// only flush if a plan has been changed out from under us
-		return nil
+	if isInvalidCachedPlanError {
+		c.stmtsToClear = append(c.stmtsToClear, sql)
 	}
-
-	c.stmtsToClear = append(c.stmtsToClear, sql)
-
-	return nil
 }
 
 func (c *LRU) clearStmt(ctx context.Context, sql string) error {
diff --git a/stmtcache/lru_test.go b/stmtcache/lru_test.go
index 58a0c378..2d620905 100644
--- a/stmtcache/lru_test.go
+++ b/stmtcache/lru_test.go
@@ -89,8 +89,7 @@ func TestLRUStmtInvalidation(t *testing.T) {
 	require.EqualValues(t, 1, cache.Len())
 	require.ElementsMatch(t, []string{"select 1"}, fetchServerStatements(t, ctx, conn))
 
-	err = cache.StatementErrored(ctx, "select 1", fakeInvalidCachePlanError)
-	require.NoError(t, err)
+	cache.StatementErrored("select 1", fakeInvalidCachePlanError)
 	_, err = cache.Get(ctx, "select 2")
 	require.NoError(t, err)
 	require.EqualValues(t, 1, cache.Len())
@@ -117,7 +116,7 @@ func TestLRUStmtInvalidation(t *testing.T) {
 	require.Error(t, res.Close())
 	require.Equal(t, byte('E'), conn.TxStatus())
 
-	err = cache.StatementErrored(ctx, "select 1", fakeInvalidCachePlanError)
+	cache.StatementErrored("select 1", fakeInvalidCachePlanError)
 	require.EqualValues(t, 1, cache.Len())
 
 	res = conn.Exec(ctx, "rollback")
@@ -156,7 +155,7 @@ func TestLRUStmtInvalidationIntegration(t *testing.T) {
 	result = conn.ExecPrepared(ctx, sd1.Name, nil, nil, nil).Read()
 	require.EqualError(t, result.Err, "ERROR: cached plan must not change result type (SQLSTATE 0A000)")
 
-	cache.StatementErrored(ctx, sql, result.Err)
+	cache.StatementErrored(sql, result.Err)
 
 	sd2, err := cache.Get(ctx, sql)
 	require.NoError(t, err)
diff --git a/stmtcache/stmtcache.go b/stmtcache/stmtcache.go
index 6e88ba54..d083e1b4 100644
--- a/stmtcache/stmtcache.go
+++ b/stmtcache/stmtcache.go
@@ -21,12 +21,10 @@ type Cache interface {
 	Clear(ctx context.Context) error
 
 	// StatementErrored informs the cache that the given statement resulted in an error when it
-	// was last used against the database. In some cases, this will cause the cache to flush
-	// the statement from the cache. It will only do so when the underlying `*pgconn.PgConn`
-	// is not currently in a transaction. If the connection is in the middle of a transaction,
-	// the bad statement will instead be flushed during the next call to Get that occurrs outside
-	// of a transaction.
-	StatementErrored(ctx context.Context, sql string, err error) error
+	// was last used against the database. In some cases, this will cause the cache to maer that
+	// statement as bad. The bad statement will instead be flushed during the next call to Get
+	// that occurs outside of a failed transaction.
+	StatementErrored(sql string, err error)
 
 	// Len returns the number of cached prepared statement descriptions.
 	Len() int