Initial commit

Author: rnben

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2024 rnben
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# go-break-select-in-for
+
+The Go linter go-break-select-in-for checks that break statement inside select statement inside for loop.
+
+For example, in myFunc the break may want to exit the outer for loop, but it doesn't work as expected.
+
+```go
+func myFunc() {
+    for {
+        select {
+        case <-ch:
+            break // should be careful
+        }
+    }
+}
+```

cmd/go-break-select-in-for/main.go

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+package main
+
+import (
+	"github.com/rnben/go-break-select-in-for/pkg/analyzer"
+	"golang.org/x/tools/go/analysis/singlechecker"
+)
+
+func main() {
+	singlechecker.Main(analyzer.Analyzer)
+}

example.go

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+package main
+
+func bad() {
+	var ch chan string
+	for {
+		select {
+		case <-ch:
+			break
+		}
+	}
+}

go.mod

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+module github.com/rnben/go-break-select-in-for
+
+go 1.18
+
+require golang.org/x/tools v0.24.0
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+)

go.sum

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+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

pkg/analyzer/analyzer.go

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+package analyzer
+
+import (
+	"go/ast"
+	"go/token"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var Analyzer = &analysis.Analyzer{
+	Name: "gobreakselectinfor",
+	Doc:  "Checks that using break statement inside select inside for loop",
+	Run:  run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+	inspect := func(node ast.Node) bool {
+		funcDecl, ok := node.(*ast.FuncDecl)
+		if !ok {
+			return true
+		}
+
+		ast.Inspect(funcDecl.Body, func(stmt ast.Node) bool {
+			if forStmt, ok := stmt.(*ast.ForStmt); ok {
+				ast.Inspect(forStmt.Body, func(stmt ast.Node) bool {
+					if selStmt, ok := stmt.(*ast.SelectStmt); ok {
+						ast.Inspect(selStmt.Body, func(stmt ast.Node) bool {
+							if brkStmt, ok := stmt.(*ast.BranchStmt); ok && brkStmt.Tok == token.BREAK {
+								pass.Reportf(stmt.Pos(), "break statement inside select statement inside for loop")
+								return true
+							}
+							return true
+						})
+					}
+					return true
+				})
+			}
+			return true
+		})
+
+		return true
+	}
+
+	for _, f := range pass.Files {
+		ast.Inspect(f, inspect)
+	}
+	return nil, nil
+}

pkg/analyzer/analyzer_test.go

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+package analyzer
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"golang.org/x/tools/go/analysis/analysistest"
+)
+
+func TestAll(t *testing.T) {
+	wd, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("Failed to get wd: %s", err)
+	}
+
+	testdata := filepath.Join(filepath.Dir(filepath.Dir(wd)), "testdata")
+	analysistest.Run(t, testdata, Analyzer, "p")
+}

testdata/src/p/p.go

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+package p
+
+func bad() {
+	var ch chan string
+	for {
+		select {
+		case <-ch:
+			break // want "break statement inside select statement inside for loop"
+		}
+	}
+}