go-exhaustruct linterのすすめ

kamakura.go #8 2026/02/27

1. go-exhaustruct linterͷ͢͢Ί Shoichi Kaji
2. ໰୊ҙࣝ package user type Input struct { Name string Age int } type User struct { Name string Age int } func New(input Input) (*User, error) { // όϦσʔγϣϯͳͲΛ͔·͢ return &User{ Name: input.Name, Age: input.Age, }, nil } user.User͕͋Δͱ͢Δ ͦΕΛ֤ॴͰ࢖͍ͬͯΔ // ࢖༻৔ॴ1 usr, err := user.New(user.Input{ Name: "Taro", Age: 25, }) // ࢖༻৔ॴ2 for _, r := range results { u, err := user.New(user.Input{ Name: r.Name, Age: r.Age, }) // ... }
3. ໰୊ҙࣝ package user type Input struct { Name string Age int Address string // ௥Ճʂ } type User struct { Name string Age int Address string } func New(input Input) (*User, error) { // όϦσʔγϣϯͳͲΛ͔·͢ return &User{ Name: input.Name, Age: input.Age, Address: input.Address, }, nil } user.UserʹAddress௥Ճ AddressΛ௥Ճ͠๨ΕΔ😢 // ࢖༻৔ॴ1 usr, err := user.New(user.Input{ Name: "Taro", Age: 25, Address: "Tokyo", // ͜͜͸ͪΌΜͱ௥Ճͨ͠ }) // ࢖༻৔ॴ2 for _, r := range results { u, err := user.New(user.Input{ Name: r.Name, Age: r.Age, // ๨Ε͍ͯΔ... }) // ... }
4. ໰୊ҙࣝ • structʹ৽ͨͳϑΟʔϧυΛ௥Ճͯ͠΋ɺgolang ͸উखʹθϩ஋Λิͬͯ͘ΕΔ • ୯ͳΔ"๨Ε"ͰϑΟʔϧυΛࢦఆ͍ͯ͠ͳͯ͘΋ ίϯύΠϧΤϥʔʹͳΒͳ͍ • ͜ͷθϩ஋ʹҙຯΛݟग़ࣗ͠ಈͰิͬͯ͘ΕΔͷ ͸golangͷ͍͍ͱ͜Ζͱ΋ݴ͑Δ͕ɺ໌ࣔతʹॻ ͘ํʹ౗͍ͨ͠ͱ͖΋͋Δ
5. ໰୊ҙࣝ • ࡢࠓɺΞϓϦέʔγϣϯΛԿ૚ʹ΋෼͚ͯߏங͢ Δ͜ͱ͕૿͍͑ͯΔ • ͦͷ৔߹ɺ֤૚ͷಠཱੑΛߴΊΔͨΊɺಉ͡ structΛ࢖͍ճ͢ͷͰ͸ͳ͘ɺ֤૚ͰstructΛݸ ผʹఆٛ͢Δ͜ͱ΋ଟ͍ • ΑͬͯɺstructͷϑΟʔϧυࢦఆ͠๨Ε໰୊͕ى ͖͏ΔՕॴ͕૿͑΍͍͢
6. https://github.com/ GaijinEntertainment/ go-exhaustruct
7. go-exhaustructͱ͸ʁ • structͷϑΟʔϧυ͕શͯ໌ࣔతʹॻ͔Ε͍ͯΔ͜ ͱΛ੩తʹݕ஌͢Δlinter • ઌͷྫͩͱɺҎԼͷΑ͏ʹAddressࢦఆ๨ΕΛݕ ஌Ͱ͖Δ👍 • ❯ golangci-lint run --enable exhaustruct ./... main.go:6:23: user.Input is missing field Address (exhaustruct) usr, err := user.New(user.Input{ ^ 1 issues: * exhaustruct: 1
8. go-exhaustructͱ͸ʁ • ͢Ͱʹgolangci-lint࢖ͬͯΔਓ͸enable exhaustructͱ͢Ε ͹Α͍ • ઃఆͰ͍Ζ͍ΖΧελϚΠζࢦఆͰ͖Δ • ࠷ॳ͸ؾʹͳΔͱ͜Ζ͚ͩenableʹ͢Δͱಋೖ͠΍͍͢ • coreͷpackage͸ignoreʹͯ͠΋Αͦ͞͏ • ࣮ࡍɺۀ຿ΞϓϦέʔγϣϯͷCIʹ૊ΈࠐΜͰ͓Γɺgo- exhaustruct༗༻ͩͳͱࢥ͍ͬͯΔ
9. ·ͱΊ • go-exhaustruct linterͷ঺հΛͨ͠ • golang͸structͷϑΟʔϧυΛࢦఆ͠ͳͯ͘΋θϩ ஋Ͱิͬͯ͘ΕΔ͕ɺͦΕ͕໰୊ʹͳΔͱ͖΋͋Δ • ϨΠϠʔυΞʔΩςΫνϟͷ࠾༻Ͱ໰୊͸ݦஶʹ • go-exhaustructͰstructͷϑΟʔϧυࢦఆ͠๨ΕΛ ੩తʹݕ஌Ͱ͖Δ