Add 'floatcompare' linter

.golangci.example.yml

@@ -285,6 +285,11 @@ linters-settings:
  - '*.Test'
  - 'example.com/package.ExampleStruct'
 
+ floatcompare:
+ # Search only for == and != no other comparisons
+ # Default: false
+ equal-only: true
+
  forbidigo:
  # Forbid the following identifiers (list of regexp).
  forbid:
@@ -1726,6 +1731,7 @@ linters:
  - exhaustive
  - exhaustivestruct
  - exportloopref
+ - floatcompare
  - forbidigo
  - forcetypeassert
  - funlen

go.mod

@@ -61,6 +61,7 @@ require (
  github.com/mitchellh/go-homedir v1.1.0
  github.com/mitchellh/go-ps v1.0.0
  github.com/moricho/tparallel v0.2.1
+ github.com/mweb/floatcompare v1.0.3
  github.com/nakabonne/nestif v0.3.1
  github.com/nishanths/exhaustive v0.7.11
  github.com/nishanths/predeclared v0.2.1
@@ -162,7 +163,7 @@ require (
  golang.org/x/exp/typeparams v0.0.0-20220218215828-6cf2b201936e // indirect
  golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
  golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
- golang.org/x/sys v0.0.0-20220319134239-a9b59b0215f8 // indirect
+ golang.org/x/sys v0.0.0-20220405052023-b1e9470b6e64 // indirect
  golang.org/x/text v0.3.7 // indirect
  golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
  google.golang.org/protobuf v1.27.1 // indirect

pkg/config/linters_settings.go

@@ -123,6 +123,7 @@ type LintersSettings struct {
  ErrorLint ErrorLintSettings
  Exhaustive ExhaustiveSettings
  ExhaustiveStruct ExhaustiveStructSettings
+ FloatCompare FloatCompareSettings
  Forbidigo ForbidigoSettings
  Funlen FunlenSettings
  Gci GciSettings
@@ -255,6 +256,10 @@ type ExhaustiveStructSettings struct {
  StructPatterns []string `mapstructure:"struct-patterns"`
 }
 
+type FloatCompareSettings struct {
+ EqualOnly bool `mapstructure:"equal-only"`
+}
+
 type ForbidigoSettings struct {
  Forbid []string `mapstructure:"forbid"`
  ExcludeGodocExamples bool `mapstructure:"exclude-godoc-examples"`

pkg/golinters/floatcompare.go

@@ -0,0 +1,29 @@
+package golinters
+
+import (
+ "github.com/mweb/floatcompare"
+ "golang.org/x/tools/go/analysis"
+
+ "github.com/golangci/golangci-lint/pkg/config"
+ "github.com/golangci/golangci-lint/pkg/golinters/goanalysis"
+)
+
+func NewFloatCompare(settings *config.FloatCompareSettings) *goanalysis.Linter {
+ a := floatcompare.NewAnalyzer()
+
+ var cfg map[string]map[string]interface{}
+ if settings != nil {
+ d := map[string]interface{}{
+ "equalOnly": settings.EqualOnly,
+ }
+
+ cfg = map[string]map[string]interface{}{a.Name: d}
+ }
+
+ return goanalysis.NewLinter(
+ a.Name,
+ a.Doc,
+ []*analysis.Analyzer{a},
+ cfg,
+ ).WithLoadMode(goanalysis.LoadModeTypesInfo)
+}

pkg/lint/lintersdb/manager.go

@@ -107,6 +107,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
  var errorlintCfg *config.ErrorLintSettings
  var exhaustiveCfg *config.ExhaustiveSettings
  var exhaustiveStructCfg *config.ExhaustiveStructSettings
+ var floatCompareStructCfg *config.FloatCompareSettings
  var gciCfg *config.GciSettings
  var goModDirectivesCfg *config.GoModDirectivesSettings
  var goMndCfg *config.GoMndSettings
@@ -140,6 +141,7 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
  errorlintCfg = &m.cfg.LintersSettings.ErrorLint
  exhaustiveCfg = &m.cfg.LintersSettings.Exhaustive
  exhaustiveStructCfg = &m.cfg.LintersSettings.ExhaustiveStruct
+ floatCompareStructCfg = &m.cfg.LintersSettings.FloatCompare
  gciCfg = &m.cfg.LintersSettings.Gci
  goModDirectivesCfg = &m.cfg.LintersSettings.GoModDirectives
  goMndCfg = &m.cfg.LintersSettings.Gomnd
@@ -289,6 +291,12 @@ func (m Manager) GetAllSupportedLinterConfigs() []*linter.Config {
  WithLoadForGoAnalysis().
  WithURL("https://github.com/kyoh86/exportloopref"),
 
+ linter.NewConfig(golinters.NewFloatCompare(floatCompareStructCfg)).
+ WithSince("v1.46.0").
+ WithPresets(linter.PresetBugs).
+ WithLoadForGoAnalysis().
+ WithURL("https://github.com/mweb/floatcompare"),
+
  linter.NewConfig(golinters.NewForbidigo()).
  WithSince("v1.34.0").
  WithPresets(linter.PresetStyle).

test/testdata/floatcompare.go

@@ -0,0 +1,71 @@
+// args: -Efloatcompare
+package testdata
+
+import "fmt"
+
+func EqualCompareIfFloats() {
+ x, y := 400., 500.
+ if 300. == 100. { // ERROR `float comparison found "300. == 100."`
+ dummy()
+ }
+ if x == y { // ERROR `float comparison found "x == y"`
+ dummy()
+ }
+ if 300.+200. == 10. { // ERROR `float comparison found "300.+200. == 10."`
+ dummy()
+ }
+ if 300 == 200 {
+ dummy()
+ }
+}
+
+func NotEqualCompareIfFloats() {
+ x, y := 400., 500.
+ if 300. != 100. { // ERROR `float comparison found "300. != 100."`
+
+ dummy()
+ }
+ if x != y { // ERROR `float comparison found "x != y"`
+ dummy()
+ }
+}
+
+func EqualCompareIfCustomType() {
+ type number float64
+ var x, y number = 300., 400.
+ if x == y { // ERROR `float comparison found "x == y"`
+ dummy()
+ }
+}
+
+func GreaterLessCompareIfFloats() {
+ if 300. >= 100. { // ERROR `float comparison found "300. >= 100."`
+ dummy()
+ }
+ if 300. <= 100. { // ERROR `float comparison found "300. <= 100."`
+ dummy()
+ }
+ if 300. < 100. { // ERROR `float comparison found "300. < 100."`
+ dummy()
+ }
+ if 300. > 100. { // ERROR `float comparison found "300. > 100."`
+ dummy()
+ }
+}
+
+func SwitchStmtWithFloat() {
+ switch 300. { // ERROR "float comparison with switch statement"
+ case 100.:
+ case 200:
+ }
+}
+
+func EqualCompareSwitchFloats() {
+ switch {
+ case 100. == 200.: // ERROR `float comparison found "100. == 200."`
+ }
+}
+
+func dummy() {
+ fmt.Println("dummy()")
+}