Linting code base with 1.6 panics while 1.5.1 worked

[ChristianWieck]

Describe the bug
When linting our code base with 1.6 a panic is raised. Linting the same code base with 1.5.1 worked without any problems.

To Reproduce
Steps to reproduce the behavior:

1. I updated revive go install github.com/mgechev/revive@latest
2. I run it with the following flags & configuration file:

revive -config revive_config.toml -formatter friendly -set_exit_status ./...

TOML

ignoreGeneratedHeader = false
severity = "warning"
confidence = 0.8
errorCode = 0
warningCode = 0

# Configuration of the `cyclomatic` rule. Here we specify that
# the rule should fail if it detects code with higher complexity than 10.
[rule.cyclomatic]
arguments = [15]

# [rule.add-constant]
# arguments = [
#     { maxLitCount = "3", allowStrs = "\"\"", allowInts = "0,1,2", allowFloats = "0.0,0.,1.0,1.,2.0,2.", ignoreFuncs = "os\\.*,fmt\\.Println,make,Test\\.*,Benchmark\\.*" },
# ]
[rule.atomic] # Prevent misuse of atomic.Value
[rule.banned-characters] # Prevents the use of certain characters in identifiers
arguments = ["Ω", "Σ", "σ"]
[rule.bare-return] # Prevents the use of naked returns
[rule.blank-imports]
[rule.bool-literal-in-expr]
[rule.comment-spacings]
[rule.confusing-naming]
[rule.confusing-results]
[rule.constant-logical-expr]
[rule.context-as-argument]
[rule.context-keys-type]
[rule.datarace]
[rule.deep-exit]
[rule.defer]
[rule.dot-imports]
[rule.duplicated-imports]
[rule.early-return]
[rule.empty-block]
[rule.empty-lines]
[rule.enforce-map-style]
arguments = ["make"]
[rule.enforce-repeated-arg-type-style]
arguments = []
[rule.enforce-slice-style]
arguments = ["make"]
[rule.error-naming]
[rule.error-return]
[rule.error-strings]
[rule.errorf]
# [rule.exported]
[rule.function-result-limit]
arguments = [3]
[rule.get-return]
[rule.identical-branches]
[rule.if-return]
[rule.increment-decrement]
[rule.indent-error-flow]
[rule.line-length-limit]
arguments = [100]
[rule.modifies-parameter]
[rule.modifies-value-receiver]
[rule.nested-structs]
[rule.optimize-operands-order]
[rule.range]
[rule.receiver-naming]
[rule.redefines-builtin-id]
[rule.string-of-int]
[rule.superfluous-else]
[rule.time-equal]
[rule.time-naming]
[rule.unchecked-type-assertion]
[rule.unconditional-recursion]
[rule.unexported-naming]
[rule.unexported-return]
[rule.unnecessary-stmt]
[rule.unreachable-code]
[rule.unused-parameter]
[rule.unused-receiver]
[rule.use-any]
[rules.use-errors-new]
[rules.useless-break]
[rule.var-declaration]
[rule.var-naming]
[rule.waitgroup-by-value]

Expected behavior
Liniting shouldn't panic as with 1.5.1

Logs
Stacktrace

panic: not supported type *ast.IndexExpr

goroutine 42 [running]:
github.com/mgechev/revive/internal/astutils.getFieldTypeName({0x965038?, 0xc000558360?})
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/internal/astutils/ast_utils.go:75 +0x145
github.com/mgechev/revive/internal/astutils.getTypeNames(0x30?)
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/internal/astutils/ast_utils.go:52 +0xac
github.com/mgechev/revive/internal/astutils.FuncSignatureIs(0xc0004ca720, {0x8af5de?, 0xc0000c1938?}, {0xc0004adaf0, 0x2, 0x46d198?}, {0xc0004adae8, 0x0, 0xc0004adb50?})
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/internal/astutils/ast_utils.go:19 +0x8d
github.com/mgechev/revive/lint.getSortableMethodFlagForFunction(0xc0004ca720)
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/lint/package.go:213 +0x165
github.com/mgechev/revive/lint.(*Package).scanSortable(0xc000696000)
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/lint/package.go:173 +0x2fa
github.com/mgechev/revive/lint.(*Package).lint(0xc000696000, {0xc0000ed688, 0x39, 0x47}, {0x0, 0x3fe999999999999a, {0xc000038d2a, 0x7}, 0x0, 0xc0001d7d70, ...}, ...)
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/lint/package.go:186 +0x47
github.com/mgechev/revive/lint.(*Linter).lintPackage(0xc0001f9c20, {0xc0001f9b50, 0x1, 0x0?}, 0xc000397db0, {0xc0000ed688, 0x39, 0x47}, {0x0, 0x3fe999999999999a, ...}, ...)
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/lint/linter.go:158 +0x35b
github.com/mgechev/revive/lint.(*Linter).Lint.func1()
        /home/cw/go/pkg/mod/github.com/mgechev/revive@v1.6.0/lint/linter.go:109 +0xa5
golang.org/x/sync/errgroup.(*Group).Go.func1()
        /home/cw/go/pkg/mod/golang.org/x/sync@v0.10.0/errgroup/errgroup.go:78 +0x50
created by golang.org/x/sync/errgroup.(*Group).Go in goroutine 1
        /home/cw/go/pkg/mod/golang.org/x/sync@v0.10.0/errgroup/errgroup.go:75 +0x96

Desktop (please complete the following information):

• OS: WSL-2 and Ubuntu 22.04
• Go: 1.23.4

Additional context
Unfortunatly I'm unable to share the code which causes the error as it's company intern. If you have any concrete questions, I might be able to provide extracts from it.

[chavacava]

Hi @ChristianWieck, thanks for reporting the problem.
The panic is triggered when checking for function signatures of the sortable interface.
Could you please share the signature (no need of the function body) of methods named Len, Less or Swap in your code base?

[ChristianWieck]

Hey, thanks for the reply. I was able to narrow down the problematic package. It's actually short and generic enough that I can share it with you:

package synchronize

import (
	"sync/atomic"
)

// Synchronized is a container type that allows thread-safe access to it's internal value.
type Synchronized[T any] interface {
	Get() T
	Set(value T)
	Swap(other Synchronized[T])
}

type synchronized[T any] struct {
	value atomic.Pointer[T]
}

// New creates a new Synchronized object of type T with it's default value.
func New[T any]() Synchronized[T] {
	return &synchronized[T]{
		value: atomic.Pointer[T]{},
	}
}

// NewValue creates a new Synchronized object of type T with the given value.
func NewValue[T any](value T) Synchronized[T] {
	syncObj := &synchronized[T]{
		value: atomic.Pointer[T]{},
	}
	syncObj.value.Store(&value)
	return syncObj
}

// Get the value of the Synchronized object. This method is thread-safe.
func (s *synchronized[T]) Get() T {
	return *s.value.Load()
}

// Set the value of the Synchronzed object. This method is thread-safe.
func (s *synchronized[T]) Set(value T) {
	s.value.Store(&value)
}

// Swap the value of the Synchronized object with the other Synchronized object.
func (s *synchronized[T]) Swap(other Synchronized[T]) {
	oldValue := s.Get()
	s.Set(other.Get())
	other.Set(oldValue)
}

Hope that helps 😄

[chavacava]

@ChristianWieck thanks for the code snippet, it confirmed my guess on the root of the problem.
I've pushed the branch https://github.com/mgechev/revive/tree/fix/issue-1217 (and its corresponding PR)
Could you please check if the branch's version is able to analyse your code without panics.

[ChristianWieck]

@chavacava yep, your commit fixed the panic - it's working again now.