antonboom / nilnil

The Golang linter that checks that there is no simultaneous return of `nil` error and an invalid value.

Anton Telyshev (Антон Телышев)

Solution Architect (ex Lead Go Developer) at Exness 💹
Look my way at Linkedin 👨‍💻

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Author and teacher of «GOLANG NINJA» online courses:

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nilnil's Issues

Detect reverse situation?

return entity, errors.New("something went wrong")

// should be
return nil, errors.New("something went wrong")

Doesn't work with multiple packages

To reproduce, add this to the examples:

import "examples/other"

func iface2() (other.Iface, error) {
	return nil, nil // want "return both the `nil` error and invalid value: use a sentinel error instead"
}

And add this to a new package under "examples":

package other

type Iface interface {
	Do()
}

Reading the code of the linter, the package of the type is not considered in the analysis and *ast.SelectorExpr is not traversed in isDangerNilType, so only types form the same package are analyzed.

One way to "fix" this might be to create a config that bypasses this type based analysis entirely by saying "all types should be checked". That still wouldn't work if a custom config is given and typed based analysis is still desired, but I think it would work for most users.

module go version

It's possible for you to downgrade the version inside your go.mod to go1.20?

the new way to handle the module and go version is strict.

https://github.com/golangci/golangci-lint/actions/runs/5893637045/job/15985603630?pr=4023

https://go.dev/blog/toolchain

golangci/golangci-lint#4023

panic: runtime error when using nilnil ./...

go version: go version go1.22.1 darwin/arm64
nilnil version: v0.1.7

command: nilnil ./...

error message:

panic: runtime error: invalid memory address or nil pointer dereference [recovered]
        panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x0 pc=0x1004baac4]

goroutine 3 [running]:
go/types.(*Checker).handleBailout(0x14000356400, 0x1400158bb98)
        /opt/homebrew/opt/go/libexec/src/go/types/check.go:367 +0x9c
panic({0x100693d80?, 0x100897ca0?})
        /opt/homebrew/opt/go/libexec/src/runtime/panic.go:770 +0x124
go/types.(*StdSizes).Sizeof(0x0, {0x1006ea5e8, 0x10089b8a0})
        /opt/homebrew/opt/go/libexec/src/go/types/sizes.go:228 +0x314
go/types.(*Config).sizeof(...)
        /opt/homebrew/opt/go/libexec/src/go/types/sizes.go:333
go/types.representableConst.func1({0x1006ea5e8?, 0x10089b8a0?})
        /opt/homebrew/opt/go/libexec/src/go/types/const.go:76 +0x9c
go/types.representableConst({0x1006eb928, 0x1008906f0}, 0x14000356400, 0x10089b8a0, 0x1400158b2e8)
        /opt/homebrew/opt/go/libexec/src/go/types/const.go:92 +0x138
go/types.(*Checker).representation(0x14000356400, 0x140015a7c00, 0x10089b8a0)
        /opt/homebrew/opt/go/libexec/src/go/types/const.go:256 +0x68
go/types.(*Checker).implicitTypeAndValue(0x14000356400, 0x140015a7c00, {0x1006ea5e8, 0x10089b8a0})
        /opt/homebrew/opt/go/libexec/src/go/types/expr.go:375 +0x304
go/types.(*Checker).assignment(0x14000356400, 0x140015a7c00, {0x1006ea5e8, 0x10089b8a0}, {0x1005e6e4c, 0x14})
        /opt/homebrew/opt/go/libexec/src/go/types/assignments.go:52 +0x23c
go/types.(*Checker).initConst(0x14000356400, 0x14000e6aae0, 0x140015a7c00)
        /opt/homebrew/opt/go/libexec/src/go/types/assignments.go:126 +0x274
go/types.(*Checker).constDecl(0x14000356400, 0x14000e6aae0, {0x1006eab88, 0x1400051e220}, {0x1006eaeb8, 0x140013260f0}, 0x0)
        /opt/homebrew/opt/go/libexec/src/go/types/decl.go:490 +0x250
go/types.(*Checker).objDecl(0x14000356400, {0x1006ee138, 0x14000e6aae0}, 0x0)
        /opt/homebrew/opt/go/libexec/src/go/types/decl.go:191 +0x84c
go/types.(*Checker).packageObjects(0x14000356400)
        /opt/homebrew/opt/go/libexec/src/go/types/resolver.go:693 +0x468
go/types.(*Checker).checkFiles(0x14000356400, {0x140009f9500, 0xb, 0xb})
        /opt/homebrew/opt/go/libexec/src/go/types/check.go:408 +0x164
go/types.(*Checker).Files(...)
        /opt/homebrew/opt/go/libexec/src/go/types/check.go:372
golang.org/x/tools/go/packages.(*loader).loadPackage(0x1400010e000, 0x140002278f0)
        /Users/jinwu.li/go/pkg/mod/golang.org/x/[email protected]/go/packages/packages.go:1058 +0x8cc
golang.org/x/tools/go/packages.(*loader).loadRecursive.func1()
        /Users/jinwu.li/go/pkg/mod/golang.org/x/[email protected]/go/packages/packages.go:854 +0x178
sync.(*Once).doSlow(0x0?, 0x0?)
        /opt/homebrew/opt/go/libexec/src/sync/once.go:74 +0x100
sync.(*Once).Do(...)
        /opt/homebrew/opt/go/libexec/src/sync/once.go:65
golang.org/x/tools/go/packages.(*loader).loadRecursive(0x0?, 0x0?)
        /Users/jinwu.li/go/pkg/mod/golang.org/x/[email protected]/go/packages/packages.go:842 +0x50
golang.org/x/tools/go/packages.(*loader).refine.func2(0x0?)
        /Users/jinwu.li/go/pkg/mod/golang.org/x/[email protected]/go/packages/packages.go:777 +0x30
created by golang.org/x/tools/go/packages.(*loader).refine in goroutine 1
        /Users/jinwu.li/go/pkg/mod/golang.org/x/[email protected]/go/packages/packages.go:776 +0xaa4