ruleguard: implement Var.Object.IsGlobal() predicate (#370)

quasilyte · Feb 2, 2022 · cb19258 · cb19258
1 parent 0e209b8
commit cb19258
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Showing 9 changed files with 86 additions and 32 deletions.
diff --git a/analyzer/testdata/src/filtertest/f1.go b/analyzer/testdata/src/filtertest/f1.go
@@ -872,3 +872,23 @@ func detectNode() {
 	nodeTest(rows[0][5], "IndexExpr") // want `true`
 	nodeTest("42", "IndexExpr")
 }
+
+var globalVar string
+var globalVar2 string = time.Now().String() // want `\Qglobal var`
+var globalVar3 = time.Now().String()        // want `\Qglobal var`
+var (
+	globalVar4 string
+)
+
+func detectGlobal() {
+	globalVar = time.Now().String()  // want `\Qglobal var`
+	globalVar4 = time.Now().String() // want `\Qglobal var`
+	{
+		globalVar := time.Now().String() // shadowed global var
+		print(globalVar)
+	}
+	{
+		var globalVar = time.Now().String() // shadowed global var
+		print(globalVar)
+	}
+}
diff --git a/analyzer/testdata/src/filtertest/rules.go b/analyzer/testdata/src/filtertest/rules.go
@@ -263,4 +263,11 @@ func testRules(m dsl.Matcher) {
 	m.Match(`typeTest($x, $y, "identical types")`).
 		Where(m["x"].Type.IdenticalTo(m["y"])).
 		Report(`true`)
+
+	m.Match(`$x = time.Now().String()`,
+		`var $x = time.Now().String()`,
+		`var $x $_ = time.Now().String()`,
+		`$x := time.Now().String()`).
+		Where(m["x"].Object.IsGlobal()).
+		Report(`global var`)
 }
diff --git a/go.mod b/go.mod
@@ -5,7 +5,7 @@ go 1.17
 require (
 	github.com/go-toolsmith/astcopy v1.0.0
 	github.com/google/go-cmp v0.5.6
-	github.com/quasilyte/go-ruleguard/dsl v0.3.15
+	github.com/quasilyte/go-ruleguard/dsl v0.3.16
 	github.com/quasilyte/go-ruleguard/rules v0.0.0-20211022131956-028d6511ab71
 	github.com/quasilyte/gogrep v0.0.0-20220120141003-628d8b3623b5
 	github.com/quasilyte/stdinfo v0.0.0-20220114132959-f7386bf02567

diff --git a/go.sum b/go.sum
@@ -10,8 +10,8 @@ github.com/google/go-cmp v0.5.6 h1:BKbKCqvP6I+rmFHt06ZmyQtvB8xAkWdhFyr0ZUNZcxQ=
 github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/quasilyte/go-ruleguard v0.3.1-0.20210203134552-1b5a410e1cc8/go.mod h1:KsAh3x0e7Fkpgs+Q9pNLS5XpFSvYCEVl5gP9Pp1xp30=
 github.com/quasilyte/go-ruleguard/dsl v0.3.0/go.mod h1:KeCP03KrjuSO0H1kTuZQCWlQPulDV6YMIXmpQss17rU=
-github.com/quasilyte/go-ruleguard/dsl v0.3.15 h1:rClYn6lk8wUV5kXnQG4JVsRQjZhSetaNtwml5wkFp5g=
-github.com/quasilyte/go-ruleguard/dsl v0.3.15/go.mod h1:KeCP03KrjuSO0H1kTuZQCWlQPulDV6YMIXmpQss17rU=
+github.com/quasilyte/go-ruleguard/dsl v0.3.16 h1:yJtIpd4oyNS+/c/gKqxNwoGO9+lPOsy1A4BzKjJRcrI=
+github.com/quasilyte/go-ruleguard/dsl v0.3.16/go.mod h1:KeCP03KrjuSO0H1kTuZQCWlQPulDV6YMIXmpQss17rU=
 github.com/quasilyte/go-ruleguard/rules v0.0.0-20201231183845-9e62ed36efe1/go.mod h1:7JTjp89EGyU1d6XfBiXihJNG37wB2VRkd125Q1u7Plc=
 github.com/quasilyte/go-ruleguard/rules v0.0.0-20211022131956-028d6511ab71 h1:CNooiryw5aisadVfzneSZPswRWvnVW8hF1bS/vo8ReI=
 github.com/quasilyte/go-ruleguard/rules v0.0.0-20211022131956-028d6511ab71/go.mod h1:4cgAphtvu7Ftv7vOT2ZOYhC6CvBxZixcasr8qIOTA50=

diff --git a/ruleguard/filters.go b/ruleguard/filters.go
@@ -7,12 +7,13 @@ import (
 	"go/types"
 	"path/filepath"
 
+	"github.com/quasilyte/gogrep"
+	"github.com/quasilyte/gogrep/nodetag"
+
 	"github.com/quasilyte/go-ruleguard/internal/xtypes"
 	"github.com/quasilyte/go-ruleguard/ruleguard/quasigo"
 	"github.com/quasilyte/go-ruleguard/ruleguard/textmatch"
 	"github.com/quasilyte/go-ruleguard/ruleguard/typematch"
-	"github.com/quasilyte/gogrep"
-	"github.com/quasilyte/gogrep/nodetag"
 )
 
 const filterSuccess = matchFilterResult("")
@@ -363,6 +364,18 @@ func makeLineFilter(src, varname string, op token.Token, rhsVarname string) filt
 	}
 }
 
+func makeObjectIsGlobalFilter(src, varname string) filterFunc {
+	return func(params *filterParams) matchFilterResult {
+		obj := params.ctx.Types.ObjectOf(identOf(params.subExpr(varname)))
+		globalScope := params.ctx.Pkg.Scope()
+		if obj.Parent() == globalScope {
+			return filterSuccess
+		}
+
+		return filterFailure(src)
+	}
+}
+
 func makeGoVersionFilter(src string, op token.Token, version GoVersion) filterFunc {
 	return func(params *filterParams) matchFilterResult {
 		if params.ctx.GoVersion.IsAny() {

diff --git a/ruleguard/ir/filter_op.gen.go b/ruleguard/ir/filter_op.gen.go
diff --git a/ruleguard/ir/gen_filter_op.go b/ruleguard/ir/gen_filter_op.go
@@ -1,3 +1,4 @@
+//go:build generate
 // +build generate
 
 package main
@@ -52,6 +53,7 @@ func main() {
 		{name: "VarFilter", comment: "m[$Value].Filter($Args[0])", valueType: "string", flags: flagHasVar},
 		{name: "VarNodeIs", comment: "m[$Value].Node.Is($Args[0])", valueType: "string", flags: flagHasVar},
 		{name: "VarObjectIs", comment: "m[$Value].Object.Is($Args[0])", valueType: "string", flags: flagHasVar},
+		{name: "VarObjectIsGlobal", comment: "m[$Value].Object.IsGlobal()", valueType: "string", flags: flagHasVar},
 		{name: "VarTypeIs", comment: "m[$Value].Type.Is($Args[0])", valueType: "string", flags: flagHasVar},
 		{name: "VarTypeIdenticalTo", comment: "m[$Value].Type.IdenticalTo($Args[0])", valueType: "string", flags: flagHasVar},
 		{name: "VarTypeUnderlyingIs", comment: "m[$Value].Type.Underlying().Is($Args[0])", valueType: "string", flags: flagHasVar},

diff --git a/ruleguard/ir_loader.go b/ruleguard/ir_loader.go
@@ -11,13 +11,14 @@ import (
 	"io/ioutil"
 	"regexp"
 
+	"github.com/quasilyte/gogrep"
+	"github.com/quasilyte/gogrep/nodetag"
+
 	"github.com/quasilyte/go-ruleguard/ruleguard/goutil"
 	"github.com/quasilyte/go-ruleguard/ruleguard/ir"
 	"github.com/quasilyte/go-ruleguard/ruleguard/quasigo"
 	"github.com/quasilyte/go-ruleguard/ruleguard/textmatch"
 	"github.com/quasilyte/go-ruleguard/ruleguard/typematch"
-	"github.com/quasilyte/gogrep"
-	"github.com/quasilyte/gogrep/nodetag"
 )
 
 type irLoaderConfig struct {
@@ -675,6 +676,8 @@ func (l *irLoader) newFilter(filter ir.FilterExpr, info *filterInfo) (matchFilte
 		result.fn = makePureFilter(result.src, filter.Value.(string))
 	case ir.FilterVarConstOp:
 		result.fn = makeConstFilter(result.src, filter.Value.(string))
+	case ir.FilterVarObjectIsGlobalOp:
+		result.fn = makeObjectIsGlobalFilter(result.src, filter.Value.(string))
 	case ir.FilterVarConstSliceOp:
 		result.fn = makeConstSliceFilter(result.src, filter.Value.(string))
 	case ir.FilterVarAddressableOp:

diff --git a/ruleguard/irconv/irconv.go b/ruleguard/irconv/irconv.go
@@ -11,9 +11,10 @@ import (
 	"strings"
 
 	"github.com/go-toolsmith/astcopy"
+	"golang.org/x/tools/go/ast/astutil"
+
 	"github.com/quasilyte/go-ruleguard/ruleguard/goutil"
 	"github.com/quasilyte/go-ruleguard/ruleguard/ir"
-	"golang.org/x/tools/go/ast/astutil"
 )
 
 type Context struct {
@@ -714,6 +715,8 @@ func (conv *converter) convertFilterExprImpl(e ast.Expr) ir.FilterExpr {
 			return ir.FilterExpr{Op: ir.FilterRootNodeParentIsOp, Args: args}
 		case "Object.Is":
 			return ir.FilterExpr{Op: ir.FilterVarObjectIsOp, Value: op.varName, Args: args}
+		case "Object.IsGlobal":
+			return ir.FilterExpr{Op: ir.FilterVarObjectIsGlobalOp, Value: op.varName}
 		case "Type.HasPointers":
 			return ir.FilterExpr{Op: ir.FilterVarTypeHasPointersOp, Value: op.varName}
 		case "Type.Is":