expression: create a new context in ColumnInfos2ColumnsAndNames to ignore truncate error (#52468)

close pingcap/tidb#52366

pkg/executor/executor.go

@@ -931,13 +931,6 @@ func (e *CheckTableExec) Next(ctx context.Context, _ *chunk.Chunk) error {
 	}
 	defer func() { e.done = true }()
 
-	// See the comment of `ColumnInfos2ColumnsAndNames`. It's fixing #42341
-	originalTypeFlags := e.Ctx().GetSessionVars().StmtCtx.TypeFlags()
-	defer func() {
-		e.Ctx().GetSessionVars().StmtCtx.SetTypeFlags(originalTypeFlags)
-	}()
-	e.Ctx().GetSessionVars().StmtCtx.SetTypeFlags(originalTypeFlags.WithIgnoreTruncateErr(true))
-
 	idxNames := make([]string, 0, len(e.indexInfos))
 	for _, idx := range e.indexInfos {
 		if idx.MVIndex {

pkg/expression/expression.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	"github.com/pingcap/errors"
+	"github.com/pingcap/tidb/pkg/errctx"
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/model"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
@@ -1005,9 +1006,48 @@ func TableInfo2SchemaAndNames(ctx BuildContext, dbName model.CIStr, tbl *model.T
 	return schema, names, nil
 }
 
+type ignoreTruncateExprCtx struct {
+	BuildContext
+	EvalContext
+	tc types.Context
+	ec errctx.Context
+}
+
+// ignoreTruncate returns a new BuildContext that ignores the truncate error.
+func ignoreTruncate(ctx BuildContext) BuildContext {
+	evalCtx := ctx.GetEvalCtx()
+	tc, ec := evalCtx.TypeCtx(), evalCtx.ErrCtx()
+	if tc.Flags().IgnoreTruncateErr() && ec.LevelForGroup(errctx.ErrGroupTruncate) == errctx.LevelIgnore {
+		return ctx
+	}
+
+	tc = tc.WithFlags(tc.Flags().WithIgnoreTruncateErr(true))
+	ec = ec.WithErrGroupLevel(errctx.ErrGroupTruncate, errctx.LevelIgnore)
+
+	return &ignoreTruncateExprCtx{
+		BuildContext: ctx,
+		EvalContext:  evalCtx,
+		tc:           tc,
+		ec:           ec,
+	}
+}
+
+// GetEvalCtx implements the BuildContext.EvalCtx().
+func (ctx *ignoreTruncateExprCtx) GetEvalCtx() EvalContext {
+	return ctx
+}
+
+// TypeCtx implements the EvalContext.TypeCtx().
+func (ctx *ignoreTruncateExprCtx) TypeCtx() types.Context {
+	return ctx.tc
+}
+
+// ErrCtx implements the EvalContext.ErrCtx().
+func (ctx *ignoreTruncateExprCtx) ErrCtx() errctx.Context {
+	return ctx.ec
+}
+
 // ColumnInfos2ColumnsAndNames converts the ColumnInfo to the *Column and NameSlice.
-// This function is **unsafe** to be called concurrently, unless the `IgnoreTruncate` has been set to `true`. The only
-// known case which will call this function concurrently is `CheckTableExec`. Ref #18408 and #42341.
 func ColumnInfos2ColumnsAndNames(ctx BuildContext, dbName, tblName model.CIStr, colInfos []*model.ColumnInfo, tblInfo *model.TableInfo) ([]*Column, types.NameSlice, error) {
 	columns := make([]*Column, 0, len(colInfos))
 	names := make([]*types.FieldName, 0, len(colInfos))
@@ -1031,17 +1071,16 @@ func ColumnInfos2ColumnsAndNames(ctx BuildContext, dbName, tblName model.CIStr,
 	}
 	// Resolve virtual generated column.
 	mockSchema := NewSchema(columns...)
-	// Ignore redundant warning here.
-	flags := ctx.GetSessionVars().StmtCtx.TypeFlags()
-	if !flags.IgnoreTruncateErr() {
-		defer func() {
-			ctx.GetSessionVars().StmtCtx.SetTypeFlags(flags)
-		}()
-		ctx.GetSessionVars().StmtCtx.SetTypeFlags(flags.WithIgnoreTruncateErr(true))
-	}
 
+	truncateIgnored := false
 	for i, col := range colInfos {
 		if col.IsVirtualGenerated() {
+			if !truncateIgnored {
+				// Ignore redundant warning here.
+				ctx = ignoreTruncate(ctx)
+				truncateIgnored = true
+			}
+
 			expr, err := generatedexpr.ParseExpression(col.GeneratedExprString)
 			if err != nil {
 				return nil, nil, errors.Trace(err)

pkg/expression/expression_test.go

@@ -17,6 +17,7 @@ package expression
 import (
 	"testing"
 
+	"github.com/pingcap/tidb/pkg/errctx"
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/model"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
@@ -295,3 +296,34 @@ func TestExpressionMemeoryUsage(t *testing.T) {
 	c4 := Constant{Value: types.NewStringDatum("11")}
 	require.Greater(t, c4.MemoryUsage(), c3.MemoryUsage())
 }
+
+func TestIgnoreTruncateExprCtx(t *testing.T) {
+	ctx := createContext(t)
+	ctx.GetSessionVars().StmtCtx.SetTypeFlags(types.StrictFlags)
+	evalCtx := ctx.GetEvalCtx()
+	tc, ec := evalCtx.TypeCtx(), evalCtx.ErrCtx()
+	require.True(t, !tc.Flags().IgnoreTruncateErr() && !tc.Flags().TruncateAsWarning())
+	require.Equal(t, errctx.LevelError, ec.LevelForGroup(errctx.ErrGroupTruncate))
+
+	// new ctx will ignore truncate error
+	newEvalCtx := ignoreTruncate(ctx).GetEvalCtx()
+	tc, ec = newEvalCtx.TypeCtx(), newEvalCtx.ErrCtx()
+	require.True(t, tc.Flags().IgnoreTruncateErr() && !tc.Flags().TruncateAsWarning())
+	require.Equal(t, errctx.LevelIgnore, ec.LevelForGroup(errctx.ErrGroupTruncate))
+
+	// old eval ctx will not change
+	tc, ec = evalCtx.TypeCtx(), evalCtx.ErrCtx()
+	require.True(t, !tc.Flags().IgnoreTruncateErr() && !tc.Flags().TruncateAsWarning())
+	require.Equal(t, errctx.LevelError, ec.LevelForGroup(errctx.ErrGroupTruncate))
+
+	// old build ctx will not change
+	evalCtx = ctx.GetEvalCtx()
+	tc, ec = evalCtx.TypeCtx(), evalCtx.ErrCtx()
+	require.True(t, !tc.Flags().IgnoreTruncateErr() && !tc.Flags().TruncateAsWarning())
+	require.Equal(t, errctx.LevelError, ec.LevelForGroup(errctx.ErrGroupTruncate))
+
+	// truncate ignored ctx will not create new ctx
+	ctx.GetSessionVars().StmtCtx.SetTypeFlags(types.StrictFlags.WithIgnoreTruncateErr(true))
+	newCtx := ignoreTruncate(ctx)
+	require.Same(t, ctx, newCtx)
+}