sql: step the sql transaction before commit

In cockroachdb#86153 we added logic to step the transaction before auto-commit. This was
insufficient to resolve cockroachdb#86132 because we did not step the transaction before
committing an explicit transaction. This PR addresses that by moving the step
logic to a shared code path. It also adds a test which previously failed.

Fixes cockroachdb#86132

Release justification: bug fix

Release note: None

pkg/sql/conn_executor_exec.go

@@ -926,6 +926,18 @@ func (ex *connExecutor) commitSQLTransactionInternal(ctx context.Context) error
 	ctx, sp := tracing.EnsureChildSpan(ctx, ex.server.cfg.AmbientCtx.Tracer, "commit sql txn")
 	defer sp.Finish()
 
+	// We need to step the transaction before committing if it has stepping
+	// enabled. If it doesn't have stepping enabled, then we just set the
+	// stepping mode back to what it was.
+	prevSteppingMode := ex.state.mu.txn.ConfigureStepping(ctx, kv.SteppingEnabled)
+	if prevSteppingMode == kv.SteppingEnabled {
+		if err := ex.state.mu.txn.Step(ctx); err != nil {
+			return err
+		}
+	} else {
+		ex.state.mu.txn.ConfigureStepping(ctx, prevSteppingMode)
+	}
+
 	if err := ex.createJobs(ctx); err != nil {
 		return err
 	}
@@ -2096,10 +2108,6 @@ func (ex *connExecutor) handleAutoCommit(
 	if err != nil {
 		return ex.makeErrEvent(err, stmt)
 	}
-	if err = ex.state.mu.txn.Step(ctx); err != nil {
-		log.VEventf(ctx, 2, "AutoCommit. err: %v", err)
-		return ex.makeErrEvent(err, stmt)
-	}
 	ev, payload := ex.commitSQLTransaction(ctx, stmt, ex.commitSQLTransactionInternal)
 	if perr, ok := payload.(payloadWithError); ok {
 		err = perr.errorCause()

pkg/sql/logictest/testdata/logic_test/schema

@@ -875,6 +875,14 @@ CREATE SCHEMA sc
 statement ok
 DROP SCHEMA sc
 
+statement ok
+BEGIN;
+CREATE SCHEMA sc;
+COMMIT
+
+statement ok
+DROP SCHEMA sc
+
 statement ok
 SET CLUSTER SETTING server.eventlog.enabled = false