database/sql: fix typo bug resulting in double-Prepare

Bug reported by Blake Mizerany found while writing
his new Postgres driver.

R=golang-dev, blake.mizerany
CC=golang-dev
https://golang.org/cl/5754057

diff --git a/src/pkg/database/sql/fakedb_test.go b/src/pkg/database/sql/fakedb_test.go
index fc63f03740ac0a4e68310f0935231040e5dd4d36..3bbbb430b49d9206f69b06cea76e518fe609757f 100644 (file)
--- a/src/pkg/database/sql/fakedb_test.go
+++ b/src/pkg/database/sql/fakedb_test.go
@@ -82,6 +82,7 @@ type fakeConn struct {
        mu          sync.Mutex
        stmtsMade   int
        stmtsClosed int
+       numPrepare  int
 }
 
 func (c *fakeConn) incrStat(v *int) {
@@ -339,6 +340,7 @@ func (c *fakeConn) prepareInsert(stmt *fakeStmt, parts []string) (driver.Stmt, e
 }
 
 func (c *fakeConn) Prepare(query string) (driver.Stmt, error) {
+       c.numPrepare++
        if c.db == nil {
                panic("nil c.db; conn = " + fmt.Sprintf("%#v", c))
        }

diff --git a/src/pkg/database/sql/sql.go b/src/pkg/database/sql/sql.go
index 62b551d89b537ae098ce9f6723df850d660a85b4..f50daa11a1fc242753b0949aaf134967b7f63aee 100644 (file)
--- a/src/pkg/database/sql/sql.go
+++ b/src/pkg/database/sql/sql.go
@@ -700,7 +700,7 @@ func (s *Stmt) connStmt() (ci driver.Conn, releaseConn func(), si driver.Stmt, e
        for _, v := range s.css {
                // TODO(bradfitz): lazily clean up entries in this
                // list with dead conns while enumerating
-               if _, match = s.db.connIfFree(cs.ci); match {
+               if _, match = s.db.connIfFree(v.ci); match {
                        cs = v
                        break
                }

diff --git a/src/pkg/database/sql/sql_test.go b/src/pkg/database/sql/sql_test.go
index c985a10beee627492803d835e1d74ceb807c49a3..e6b92a941baf618c0837dc1c0a9a2cf09121abf9 100644 (file)
--- a/src/pkg/database/sql/sql_test.go
+++ b/src/pkg/database/sql/sql_test.go
@@ -47,9 +47,19 @@ func closeDB(t *testing.T, db *DB) {
        }
 }
 
+// numPrepares assumes that db has exactly 1 idle conn and returns
+// its count of calls to Prepare
+func numPrepares(t *testing.T, db *DB) int {
+       if n := len(db.freeConn); n != 1 {
+               t.Fatalf("free conns = %d; want 1", n)
+       }
+       return db.freeConn[0].(*fakeConn).numPrepare
+}
+
 func TestQuery(t *testing.T) {
        db := newTestDB(t, "people")
        defer closeDB(t, db)
+       prepares0 := numPrepares(t, db)
        rows, err := db.Query("SELECT|people|age,name|")
        if err != nil {
                t.Fatalf("Query: %v", err)
@@ -83,7 +93,10 @@ func TestQuery(t *testing.T) {
        // And verify that the final rows.Next() call, which hit EOF,
        // also closed the rows connection.
        if n := len(db.freeConn); n != 1 {
-               t.Errorf("free conns after query hitting EOF = %d; want 1", n)
+               t.Fatalf("free conns after query hitting EOF = %d; want 1", n)
+       }
+       if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
+               t.Errorf("executed %d Prepare statements; want 1", prepares)
        }
 }