expression: remove direct dependencies with sessionctx.Context for …

…package `expression` (#51025)

close #51024

pkg/expression/BUILD.bazel

@@ -207,7 +207,6 @@ go_test(
         "//pkg/parser/terror",
         "//pkg/planner/core",
         "//pkg/session",
-        "//pkg/sessionctx",
         "//pkg/sessionctx/stmtctx",
         "//pkg/sessionctx/variable",
         "//pkg/sessiontxn",

pkg/expression/aggregation/BUILD.bazel

@@ -1,5 +1,13 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
+package_group(
+    name = "aggregation_friend",
+    packages = [
+        "-//pkg/sessionctx/...",
+        "//...",
+    ],
+)
+
 go_library(
     name = "aggregation",
     srcs = [
@@ -21,7 +29,9 @@ go_library(
         "window_func.go",
     ],
     importpath = "github.com/pingcap/tidb/pkg/expression/aggregation",
-    visibility = ["//visibility:public"],
+    visibility = [
+        ":aggregation_friend",
+    ],
     deps = [
         "//pkg/expression",
         "//pkg/kv",
@@ -30,7 +40,6 @@ go_library(
         "//pkg/parser/mysql",
         "//pkg/parser/terror",
         "//pkg/planner/util",
-        "//pkg/sessionctx",
         "//pkg/sessionctx/stmtctx",
         "//pkg/sessionctx/variable",
         "//pkg/types",
@@ -64,7 +73,6 @@ go_test(
         "//pkg/kv",
         "//pkg/parser/ast",
         "//pkg/parser/mysql",
-        "//pkg/sessionctx",
         "//pkg/sessionctx/stmtctx",
         "//pkg/sessionctx/variable",
         "//pkg/testkit/testsetup",

pkg/expression/aggregation/agg_to_pb.go

@@ -22,7 +22,6 @@ import (
 	"github.com/pingcap/tidb/pkg/expression"
 	"github.com/pingcap/tidb/pkg/kv"
 	"github.com/pingcap/tidb/pkg/parser/ast"
-	"github.com/pingcap/tidb/pkg/sessionctx"
 	"github.com/pingcap/tidb/pkg/sessionctx/variable"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/codec"
@@ -184,7 +183,7 @@ func PBAggFuncModeToAggFuncMode(pbMode *tipb.AggFunctionMode) (mode AggFunctionM
 }
 
 // PBExprToAggFuncDesc converts pb to aggregate function.
-func PBExprToAggFuncDesc(ctx sessionctx.Context, aggFunc *tipb.Expr, fieldTps []*types.FieldType) (*AggFuncDesc, error) {
+func PBExprToAggFuncDesc(ctx expression.BuildContext, aggFunc *tipb.Expr, fieldTps []*types.FieldType) (*AggFuncDesc, error) {
 	var name string
 	switch aggFunc.Tp {
 	case tipb.ExprType_Count:

pkg/expression/aggregation/aggregation.go

@@ -23,7 +23,6 @@ import (
 	"github.com/pingcap/tidb/pkg/kv"
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
-	"github.com/pingcap/tidb/pkg/sessionctx"
 	"github.com/pingcap/tidb/pkg/sessionctx/stmtctx"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
@@ -51,7 +50,7 @@ type Aggregation interface {
 }
 
 // NewDistAggFunc creates new Aggregate function for mock tikv.
-func NewDistAggFunc(expr *tipb.Expr, fieldTps []*types.FieldType, ctx sessionctx.Context) (Aggregation, *AggFuncDesc, error) {
+func NewDistAggFunc(expr *tipb.Expr, fieldTps []*types.FieldType, ctx expression.BuildContext) (Aggregation, *AggFuncDesc, error) {
 	args := make([]expression.Expression, 0, len(expr.Children))
 	for _, child := range expr.Children {
 		arg, err := expression.PBToExpr(ctx, child, fieldTps)

pkg/expression/aggregation/aggregation_test.go

@@ -21,7 +21,6 @@ import (
 	"github.com/pingcap/tidb/pkg/expression"
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
-	"github.com/pingcap/tidb/pkg/sessionctx"
 	"github.com/pingcap/tidb/pkg/sessionctx/variable"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
@@ -30,7 +29,7 @@ import (
 )
 
 type mockAggFuncSuite struct {
-	ctx     sessionctx.Context
+	ctx     expression.BuildContext
 	rows    []chunk.Row
 	nullRow chunk.Row
 }

pkg/expression/aggregation/base_func.go

@@ -25,7 +25,6 @@ import (
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/charset"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
-	"github.com/pingcap/tidb/pkg/sessionctx"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/chunk"
 	"github.com/pingcap/tidb/pkg/util/mathutil"
@@ -42,13 +41,13 @@ type baseFuncDesc struct {
 	RetTp *types.FieldType
 }
 
-func newBaseFuncDesc(ctx sessionctx.Context, name string, args []expression.Expression) (baseFuncDesc, error) {
+func newBaseFuncDesc(ctx expression.BuildContext, name string, args []expression.Expression) (baseFuncDesc, error) {
 	b := baseFuncDesc{Name: strings.ToLower(name), Args: args}
 	err := b.TypeInfer(ctx)
 	return b, err
 }
 
-func (a *baseFuncDesc) equal(ctx sessionctx.Context, other *baseFuncDesc) bool {
+func (a *baseFuncDesc) equal(ctx expression.EvalContext, other *baseFuncDesc) bool {
 	if a.Name != other.Name || len(a.Args) != len(other.Args) {
 		return false
 	}
@@ -86,18 +85,18 @@ func (a *baseFuncDesc) String() string {
 }
 
 // TypeInfer infers the arguments and return types of an function.
-func (a *baseFuncDesc) TypeInfer(ctx sessionctx.Context) error {
+func (a *baseFuncDesc) TypeInfer(ctx expression.BuildContext) error {
 	switch a.Name {
 	case ast.AggFuncCount:
-		a.typeInfer4Count(ctx)
+		a.typeInfer4Count()
 	case ast.AggFuncApproxCountDistinct:
-		a.typeInfer4ApproxCountDistinct(ctx)
+		a.typeInfer4ApproxCountDistinct()
 	case ast.AggFuncApproxPercentile:
 		return a.typeInfer4ApproxPercentile(ctx)
 	case ast.AggFuncSum:
-		a.typeInfer4Sum(ctx)
+		a.typeInfer4Sum()
 	case ast.AggFuncAvg:
-		a.typeInfer4Avg(ctx)
+		a.typeInfer4Avg()
 	case ast.AggFuncGroupConcat:
 		a.typeInfer4GroupConcat(ctx)
 	case ast.AggFuncMax, ast.AggFuncMin, ast.AggFuncFirstRow,
@@ -116,9 +115,9 @@ func (a *baseFuncDesc) TypeInfer(ctx sessionctx.Context) error {
 	case ast.WindowFuncLead, ast.WindowFuncLag:
 		a.typeInfer4LeadLag(ctx)
 	case ast.AggFuncVarPop, ast.AggFuncStddevPop, ast.AggFuncVarSamp, ast.AggFuncStddevSamp:
-		a.typeInfer4PopOrSamp(ctx)
+		a.typeInfer4PopOrSamp()
 	case ast.AggFuncJsonArrayagg:
-		a.typeInfer4JsonArrayAgg(ctx)
+		a.typeInfer4JsonArrayAgg()
 	case ast.AggFuncJsonObjectAgg:
 		return a.typeInfer4JsonObjectAgg(ctx)
 	default:
@@ -127,7 +126,7 @@ func (a *baseFuncDesc) TypeInfer(ctx sessionctx.Context) error {
 	return nil
 }
 
-func (a *baseFuncDesc) typeInfer4Count(sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4Count() {
 	a.RetTp = types.NewFieldType(mysql.TypeLonglong)
 	a.RetTp.SetFlen(21)
 	a.RetTp.SetDecimal(0)
@@ -136,11 +135,11 @@ func (a *baseFuncDesc) typeInfer4Count(sessionctx.Context) {
 	types.SetBinChsClnFlag(a.RetTp)
 }
 
-func (a *baseFuncDesc) typeInfer4ApproxCountDistinct(ctx sessionctx.Context) {
-	a.typeInfer4Count(ctx)
+func (a *baseFuncDesc) typeInfer4ApproxCountDistinct() {
+	a.typeInfer4Count()
 }
 
-func (a *baseFuncDesc) typeInfer4ApproxPercentile(ctx sessionctx.Context) error {
+func (a *baseFuncDesc) typeInfer4ApproxPercentile(ctx expression.EvalContext) error {
 	if len(a.Args) != 2 {
 		return errors.New("APPROX_PERCENTILE should take 2 arguments")
 	}
@@ -182,7 +181,7 @@ func (a *baseFuncDesc) typeInfer4ApproxPercentile(ctx sessionctx.Context) error
 
 // typeInfer4Sum should return a "decimal", otherwise it returns a "double".
 // Because child returns integer or decimal type.
-func (a *baseFuncDesc) typeInfer4Sum(sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4Sum() {
 	switch a.Args[0].GetType().GetType() {
 	case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong, mysql.TypeYear:
 		a.RetTp = types.NewFieldType(mysql.TypeNewDecimal)
@@ -221,7 +220,7 @@ func (a *baseFuncDesc) TypeInfer4FinalCount(finalCountRetType *types.FieldType)
 
 // typeInfer4Avg should returns a "decimal", otherwise it returns a "double".
 // Because child returns integer or decimal type.
-func (a *baseFuncDesc) typeInfer4Avg(sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4Avg() {
 	switch a.Args[0].GetType().GetType() {
 	case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong:
 		a.RetTp = types.NewFieldType(mysql.TypeNewDecimal)
@@ -247,7 +246,7 @@ func (a *baseFuncDesc) typeInfer4Avg(sessionctx.Context) {
 	types.SetBinChsClnFlag(a.RetTp)
 }
 
-func (a *baseFuncDesc) typeInfer4GroupConcat(ctx sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4GroupConcat(ctx expression.BuildContext) {
 	a.RetTp = types.NewFieldType(mysql.TypeVarString)
 	charset, collate := charset.GetDefaultCharsetAndCollate()
 	a.RetTp.SetCharset(charset)
@@ -263,7 +262,7 @@ func (a *baseFuncDesc) typeInfer4GroupConcat(ctx sessionctx.Context) {
 	}
 }
 
-func (a *baseFuncDesc) typeInfer4MaxMin(ctx sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4MaxMin(ctx expression.BuildContext) {
 	_, argIsScalaFunc := a.Args[0].(*expression.ScalarFunction)
 	if argIsScalaFunc && a.Args[0].GetType().GetType() == mysql.TypeFloat {
 		// For scalar function, the result of "float32" is set to the "float64"
@@ -288,20 +287,20 @@ func (a *baseFuncDesc) typeInfer4MaxMin(ctx sessionctx.Context) {
 	}
 }
 
-func (a *baseFuncDesc) typeInfer4BitFuncs(ctx sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4BitFuncs(ctx expression.BuildContext) {
 	a.RetTp = types.NewFieldType(mysql.TypeLonglong)
 	a.RetTp.SetFlen(21)
 	types.SetBinChsClnFlag(a.RetTp)
 	a.RetTp.AddFlag(mysql.UnsignedFlag | mysql.NotNullFlag)
 	a.Args[0] = expression.WrapWithCastAsInt(ctx, a.Args[0])
 }
 
-func (a *baseFuncDesc) typeInfer4JsonArrayAgg(sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4JsonArrayAgg() {
 	a.RetTp = types.NewFieldType(mysql.TypeJSON)
 	types.SetBinChsClnFlag(a.RetTp)
 }
 
-func (a *baseFuncDesc) typeInfer4JsonObjectAgg(ctx sessionctx.Context) error {
+func (a *baseFuncDesc) typeInfer4JsonObjectAgg(ctx expression.BuildContext) error {
 	a.RetTp = types.NewFieldType(mysql.TypeJSON)
 	types.SetBinChsClnFlag(a.RetTp)
 	a.Args[0] = expression.WrapWithCastAsString(ctx, a.Args[0])
@@ -333,7 +332,7 @@ func (a *baseFuncDesc) typeInfer4PercentRank() {
 	a.RetTp.SetDecimal(mysql.NotFixedDec)
 }
 
-func (a *baseFuncDesc) typeInfer4LeadLag(ctx sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4LeadLag(ctx expression.BuildContext) {
 	if len(a.Args) < 3 {
 		a.typeInfer4MaxMin(ctx)
 	} else {
@@ -343,7 +342,7 @@ func (a *baseFuncDesc) typeInfer4LeadLag(ctx sessionctx.Context) {
 	}
 }
 
-func (a *baseFuncDesc) typeInfer4PopOrSamp(sessionctx.Context) {
+func (a *baseFuncDesc) typeInfer4PopOrSamp() {
 	// var_pop/std/var_samp/stddev_samp's return value type is double
 	a.RetTp = types.NewFieldType(mysql.TypeDouble)
 	a.RetTp.SetFlen(mysql.MaxRealWidth)
@@ -398,7 +397,7 @@ var noNeedCastAggFuncs = map[string]struct{}{
 }
 
 // WrapCastForAggArgs wraps the args of an aggregate function with a cast function.
-func (a *baseFuncDesc) WrapCastForAggArgs(ctx sessionctx.Context) {
+func (a *baseFuncDesc) WrapCastForAggArgs(ctx expression.BuildContext) {
 	if len(a.Args) == 0 {
 		return
 	}

pkg/expression/aggregation/descriptor.go

@@ -26,7 +26,6 @@ import (
 	"github.com/pingcap/tidb/pkg/parser/ast"
 	"github.com/pingcap/tidb/pkg/parser/mysql"
 	"github.com/pingcap/tidb/pkg/planner/util"
-	"github.com/pingcap/tidb/pkg/sessionctx"
 	"github.com/pingcap/tidb/pkg/sessionctx/variable"
 	"github.com/pingcap/tidb/pkg/types"
 	"github.com/pingcap/tidb/pkg/util/collate"
@@ -48,7 +47,7 @@ type AggFuncDesc struct {
 
 // NewAggFuncDesc creates an aggregation function signature descriptor.
 // this func cannot be called twice as the TypeInfer has changed the type of args in the first time.
-func NewAggFuncDesc(ctx sessionctx.Context, name string, args []expression.Expression, hasDistinct bool) (*AggFuncDesc, error) {
+func NewAggFuncDesc(ctx expression.BuildContext, name string, args []expression.Expression, hasDistinct bool) (*AggFuncDesc, error) {
 	b, err := newBaseFuncDesc(ctx, name, args)
 	if err != nil {
 		return nil, err
@@ -57,7 +56,7 @@ func NewAggFuncDesc(ctx sessionctx.Context, name string, args []expression.Expre
 }
 
 // NewAggFuncDescForWindowFunc creates an aggregation function from window functions, where baseFuncDesc may be ready.
-func NewAggFuncDescForWindowFunc(ctx sessionctx.Context, desc *WindowFuncDesc, hasDistinct bool) (*AggFuncDesc, error) {
+func NewAggFuncDescForWindowFunc(ctx expression.BuildContext, desc *WindowFuncDesc, hasDistinct bool) (*AggFuncDesc, error) {
 	if desc.RetTp == nil { // safety check
 		return NewAggFuncDesc(ctx, desc.Name, desc.Args, hasDistinct)
 	}
@@ -91,7 +90,7 @@ func (a *AggFuncDesc) String() string {
 }
 
 // Equal checks whether two aggregation function signatures are equal.
-func (a *AggFuncDesc) Equal(ctx sessionctx.Context, other *AggFuncDesc) bool {
+func (a *AggFuncDesc) Equal(ctx expression.EvalContext, other *AggFuncDesc) bool {
 	if a.HasDistinct != other.HasDistinct {
 		return false
 	}
@@ -200,7 +199,7 @@ func (a *AggFuncDesc) Split(ordinal []int) (partialAggDesc, finalAggDesc *AggFun
 // +------+-----------+---------+---------+------------+-------------+------------+---------+---------+------+----------+
 // |    1 |         1 |      95 | 95.0000 |         95 |          95 |         95 |      95 |      95 | NULL |     NULL |
 // +------+-----------+---------+---------+------------+-------------+------------+---------+---------+------+----------+
-func (a *AggFuncDesc) EvalNullValueInOuterJoin(ctx sessionctx.Context, schema *expression.Schema) (types.Datum, bool) {
+func (a *AggFuncDesc) EvalNullValueInOuterJoin(ctx expression.BuildContext, schema *expression.Schema) (types.Datum, bool) {
 	switch a.Name {
 	case ast.AggFuncCount:
 		return a.evalNullValueInOuterJoin4Count(ctx, schema)
@@ -219,7 +218,7 @@ func (a *AggFuncDesc) EvalNullValueInOuterJoin(ctx sessionctx.Context, schema *e
 }
 
 // GetAggFunc gets an evaluator according to the aggregation function signature.
-func (a *AggFuncDesc) GetAggFunc(ctx sessionctx.Context) Aggregation {
+func (a *AggFuncDesc) GetAggFunc(ctx expression.BuildContext) Aggregation {
 	aggFunc := aggFunction{AggFuncDesc: a}
 	switch a.Name {
 	case ast.AggFuncSum:
@@ -258,7 +257,7 @@ func (a *AggFuncDesc) GetAggFunc(ctx sessionctx.Context) Aggregation {
 	}
 }
 
-func (a *AggFuncDesc) evalNullValueInOuterJoin4Count(ctx sessionctx.Context, schema *expression.Schema) (types.Datum, bool) {
+func (a *AggFuncDesc) evalNullValueInOuterJoin4Count(ctx expression.BuildContext, schema *expression.Schema) (types.Datum, bool) {
 	for _, arg := range a.Args {
 		result := expression.EvaluateExprWithNull(ctx, schema, arg)
 		con, ok := result.(*expression.Constant)
@@ -269,7 +268,7 @@ func (a *AggFuncDesc) evalNullValueInOuterJoin4Count(ctx sessionctx.Context, sch
 	return types.NewDatum(1), true
 }
 
-func (a *AggFuncDesc) evalNullValueInOuterJoin4Sum(ctx sessionctx.Context, schema *expression.Schema) (types.Datum, bool) {
+func (a *AggFuncDesc) evalNullValueInOuterJoin4Sum(ctx expression.BuildContext, schema *expression.Schema) (types.Datum, bool) {
 	result := expression.EvaluateExprWithNull(ctx, schema, a.Args[0])
 	con, ok := result.(*expression.Constant)
 	if !ok || con.Value.IsNull() {
@@ -278,7 +277,7 @@ func (a *AggFuncDesc) evalNullValueInOuterJoin4Sum(ctx sessionctx.Context, schem
 	return con.Value, true
 }
 
-func (a *AggFuncDesc) evalNullValueInOuterJoin4BitAnd(ctx sessionctx.Context, schema *expression.Schema) (types.Datum, bool) {
+func (a *AggFuncDesc) evalNullValueInOuterJoin4BitAnd(ctx expression.BuildContext, schema *expression.Schema) (types.Datum, bool) {
 	result := expression.EvaluateExprWithNull(ctx, schema, a.Args[0])
 	con, ok := result.(*expression.Constant)
 	if !ok || con.Value.IsNull() {
@@ -287,7 +286,7 @@ func (a *AggFuncDesc) evalNullValueInOuterJoin4BitAnd(ctx sessionctx.Context, sc
 	return con.Value, true
 }
 
-func (a *AggFuncDesc) evalNullValueInOuterJoin4BitOr(ctx sessionctx.Context, schema *expression.Schema) (types.Datum, bool) {
+func (a *AggFuncDesc) evalNullValueInOuterJoin4BitOr(ctx expression.BuildContext, schema *expression.Schema) (types.Datum, bool) {
 	result := expression.EvaluateExprWithNull(ctx, schema, a.Args[0])
 	con, ok := result.(*expression.Constant)
 	if !ok || con.Value.IsNull() {

pkg/expression/aggregation/explain.go

@@ -18,12 +18,12 @@ import (
 	"bytes"
 	"fmt"
 
+	"github.com/pingcap/tidb/pkg/expression"
 	"github.com/pingcap/tidb/pkg/parser/ast"
-	"github.com/pingcap/tidb/pkg/sessionctx"
 )
 
 // ExplainAggFunc generates explain information for a aggregation function.
-func ExplainAggFunc(ctx sessionctx.Context, agg *AggFuncDesc, normalized bool) string {
+func ExplainAggFunc(ctx expression.EvalContext, agg *AggFuncDesc, normalized bool) string {
 	var buffer bytes.Buffer
 	fmt.Fprintf(&buffer, "%s(", agg.Name)
 	if agg.HasDistinct {