database/sql: ensure driverConns are closed if not returned to pool

Previously if a connection was requested but timed out during the
request and when acquiring the db.Lock the connection request
is fulfilled and the request is unable to be returned to the
connection pool, then then driver connection would not be closed.

No tests were added or modified because I was unable to determine
how to trigger this situation without something invasive.

Change-Id: I9d4dc680e3fdcf63d79d212174a5b8b313f363f1
Reviewed-on: https://go-review.googlesource.com/36641
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index cf3334ad8570952f540c91bff54de53c38ffc7da..adf964992de58ae547dcc596ae93c3cab2f1c2e1 100644 (file)
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -939,14 +939,14 @@ func (db *DB) conn(ctx context.Context, strategy connReuseStrategy) (*driverConn
                        // on it after removing.
                        db.mu.Lock()
                        delete(db.connRequests, reqKey)
+                       db.mu.Unlock()
                        select {
                        default:
                        case ret, ok := <-req:
                                if ok {
-                                       db.putConnDBLocked(ret.conn, ret.err)
+                                       db.putConn(ret.conn, ret.err)
                                }
                        }
-                       db.mu.Unlock()
                        return nil, ctx.Err()
                case ret, ok := <-req:
                        if !ok {