Remove purego fallbacks (#325)

cespare · web-flow · commit 571a56ba783f · 2023-02-22T14:28:49.000-08:00
Having go-cmp panic when using the purego build tag makes it hard to use go-cmp for testing packages that themselves have purego fallbacks. Since go-cmp can't implement its functionality without unsafe (the "fallback" panics) and since environments that prohibit unsafe are much less common these days anyway, simply remove purego code entirely. Fixes #283.
diff --git a/cmp/export.go b/cmp/export.go
@@ -2,18 +2,13 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !purego
-// +build !purego
-
 package cmp
 
 import (
 	"reflect"
 	"unsafe"
 )
 
-const supportExporters = true
-
 // retrieveUnexportedField uses unsafe to forcibly retrieve any field from
 // a struct such that the value has read-write permissions.
 //
diff --git a/cmp/export_panic.go b/cmp/export_panic.go
diff --git a/cmp/internal/value/pointer.go b/cmp/internal/value/pointer.go
@@ -2,9 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !purego
-// +build !purego
-
 package value
 
 import (
diff --git a/cmp/internal/value/pointer_purego.go b/cmp/internal/value/pointer_purego.go
diff --git a/cmp/options.go b/cmp/options.go
@@ -403,9 +403,6 @@ func (cm comparer) String() string {
 // In other cases, the cmpopts.IgnoreUnexported option can be used to ignore
 // all unexported fields on specified struct types.
 func Exporter(f func(reflect.Type) bool) Option {
-	if !supportExporters {
-		panic("Exporter is not supported on purego builds")
-	}
 	return exporter(f)
 }
 
diff --git a/cmp/report_reflect.go b/cmp/report_reflect.go
@@ -199,7 +199,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind,
 				break
 			}
 			sf := t.Field(i)
-			if supportExporters && !isExported(sf.Name) {
+			if !isExported(sf.Name) {
 				vv = retrieveUnexportedField(v, sf, true)
 			}
 			s := opts.WithTypeMode(autoType).FormatValue(vv, t.Kind(), ptrs)

Original file line number	Diff line number	Diff line change
`@@ -403,9 +403,6 @@ func (cm comparer) String() string {`
`403`	`403`	`// In other cases, the cmpopts.IgnoreUnexported option can be used to ignore`
`404`	`404`	`// all unexported fields on specified struct types.`
`405`	`405`	`func Exporter(f func(reflect.Type) bool) Option {`
`406`		`- if !supportExporters {`
`407`		`- panic("Exporter is not supported on purego builds")`
`408`		`- }`
`409`	`406`	`return exporter(f)`
`410`	`407`	`}`
`411`	`408`
Original file line number	Diff line number	Diff line change
`@@ -199,7 +199,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind,`
`199`	`199`	`break`
`200`	`200`	`}`
`201`	`201`	`sf := t.Field(i)`
`202`		`- if supportExporters && !isExported(sf.Name) {`
	`202`	`+ if !isExported(sf.Name) {`
`203`	`203`	`vv = retrieveUnexportedField(v, sf, true)`
`204`	`204`	`}`
`205`	`205`	`s := opts.WithTypeMode(autoType).FormatValue(vv, t.Kind(), ptrs)`