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go-spew
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Enable methods to sort map keys and spew itself as last resort 

If enabled by flags, try to use methods to stringify map keys and sort on that.

If we can't use primitive sorting and we can't use methods, we can still fall
back on spew itself.  If SpewKeys is enabled, use Sprintf("%#v") to generate a
string and sort by that.
This commit is contained in:
Tim Hockin 2015-03-31 13:55:04 -07:00
parent fc32781af5
commit 3e6e67c4dc
10 changed files with 305 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
README.md
View File

@ -132,9 +132,16 @@ options. See the ConfigState documentation for more details.
Specifies map keys should be sorted before being printed. Use
this to have a more deterministic, diffable output. Note that
only native types (bool, int, uint, floats, uintptr and string)
are supported with other types sorted according to the
reflect.Value.String() output which guarantees display stability.
Natural map order is used by default.
and types which implement error or Stringer interfaces are supported,
with other types sorted according to the reflect.Value.String() output
which guarantees display stability. Natural map order is used by
default.
* SpewKeys
SpewKeys specifies that, as a last resort attempt, map keys should be
spewed to strings and sorted by those strings. This is only considered
if SortKeys is true.
```
## License

75
spew/common.go
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@ -17,6 +17,7 @@
package spew
import (
"bytes"
"fmt"
"io"
"reflect"
@ -325,7 +326,61 @@ func printHexPtr(w io.Writer, p uintptr) {
// valuesSorter implements sort.Interface to allow a slice of reflect.Value
// elements to be sorted.
type valuesSorter struct {
values []reflect.Value
values []reflect.Value
strings []string // either nil or same len and values
cs *ConfigState
}
// newValuesSorter initializes a valuesSorter instance, which holds a set of
// surrogate keys on which the data should be sorted. It uses flags in
// ConfigState to decide if and how to populate those surrogate keys.
func newValuesSorter(values []reflect.Value, cs *ConfigState) sort.Interface {
vs := &valuesSorter{values: values, cs: cs}
if canSortSimply(vs.values[0].Kind()) {
return vs
}
if !cs.DisableMethods {
vs.strings = make([]string, len(values))
for i := range vs.values {
b := bytes.Buffer{}
if !handleMethods(cs, &b, vs.values[i]) {
vs.strings = nil
break
}
vs.strings[i] = b.String()
}
}
if vs.strings == nil && cs.SpewKeys {
vs.strings = make([]string, len(values))
for i := range vs.values {
vs.strings[i] = Sprintf("%#v", vs.values[i].Interface())
}
}
return vs
}
// canSortSimply tests whether a reflect.Kind is a primitive that can be sorted
// directly, or whether it should be considered for sorting by surrogate keys
// (if the ConfigState allows it).
func canSortSimply(kind reflect.Kind) bool {
// This switch parallels valueSortLess, except for the default case.
switch kind {
case reflect.Bool:
return true
case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int:
return true
case reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint:
return true
case reflect.Float32, reflect.Float64:
return true
case reflect.String:
return true
case reflect.Uintptr:
return true
case reflect.Array:
return true
}
return false
}
// Len returns the number of values in the slice. It is part of the
@ -338,6 +393,9 @@ func (s *valuesSorter) Len() int {
// sort.Interface implementation.
func (s *valuesSorter) Swap(i, j int) {
s.values[i], s.values[j] = s.values[j], s.values[i]
if s.strings != nil {
s.strings[i], s.strings[j] = s.strings[j], s.strings[i]
}
}
// valueSortLess returns whether the first value should sort before the second
@ -375,15 +433,18 @@ func valueSortLess(a, b reflect.Value) bool {
// Less returns whether the value at index i should sort before the
// value at index j. It is part of the sort.Interface implementation.
func (s *valuesSorter) Less(i, j int) bool {
return valueSortLess(s.values[i], s.values[j])
if s.strings == nil {
return valueSortLess(s.values[i], s.values[j])
}
return s.strings[i] < s.strings[j]
}
// sortValues is a generic sort function for native types: int, uint, bool,
// string and uintptr. Other inputs are sorted according to their
// Value.String() value to ensure display stability.
func sortValues(values []reflect.Value) {
// sortValues is a sort function that handles both native types and any type that
// can be converted to error or Stringer. Other inputs are sorted according to
// their Value.String() value to ensure display stability.
func sortValues(values []reflect.Value, cs *ConfigState) {
if len(values) == 0 {
return
}
sort.Sort(&valuesSorter{values})
sort.Sort(newValuesSorter(values, cs))
}

141
spew/common_test.go
View File

@ -18,9 +18,10 @@ package spew_test
import (
"fmt"
"github.com/davecgh/go-spew/spew"
"reflect"
"testing"
"github.com/davecgh/go-spew/spew"
)
// custom type to test Stinger interface on non-pointer receiver.
@ -113,9 +114,24 @@ func testFailed(result string, wants []string) bool {
return true
}
// TestSortValues ensures the sort functionality for relect.Value based sorting
// works as intended.
func TestSortValues(t *testing.T) {
type sortableStruct struct {
x int
}
func (ss sortableStruct) String() string {
return fmt.Sprintf("ss.%d", ss.x)
}
type unsortableStruct struct {
x int
}
type sortTestCase struct {
input []reflect.Value
expected []reflect.Value
}
func helpTestSortValues(tests []sortTestCase, cs *spew.ConfigState, t *testing.T) {
getInterfaces := func(values []reflect.Value) []interface{} {
interfaces := []interface{}{}
for _, v := range values {
@ -124,6 +140,23 @@ func TestSortValues(t *testing.T) {
return interfaces
}
for _, test := range tests {
spew.SortValues(test.input, cs)
// reflect.DeepEqual cannot really make sense of reflect.Value,
// probably because of all the pointer tricks. For instance,
// v(2.0) != v(2.0) on a 32-bits system. Turn them into interface{}
// instead.
input := getInterfaces(test.input)
expected := getInterfaces(test.expected)
if !reflect.DeepEqual(input, expected) {
t.Errorf("Sort mismatch:\n %v != %v", input, expected)
}
}
}
// TestSortValues ensures the sort functionality for relect.Value based sorting
// works as intended.
func TestSortValues(t *testing.T) {
v := reflect.ValueOf
a := v("a")
@ -132,10 +165,7 @@ func TestSortValues(t *testing.T) {
embedA := v(embed{"a"})
embedB := v(embed{"b"})
embedC := v(embed{"c"})
tests := []struct {
input []reflect.Value
expected []reflect.Value
}{
tests := []sortTestCase{
// No values.
{
[]reflect.Value{},
@ -176,22 +206,93 @@ func TestSortValues(t *testing.T) {
[]reflect.Value{v(uintptr(2)), v(uintptr(1)), v(uintptr(3))},
[]reflect.Value{v(uintptr(1)), v(uintptr(2)), v(uintptr(3))},
},
// SortableStructs.
{
// Note: not sorted - DisableMethods is set.
[]reflect.Value{v(sortableStruct{2}), v(sortableStruct{1}), v(sortableStruct{3})},
[]reflect.Value{v(sortableStruct{2}), v(sortableStruct{1}), v(sortableStruct{3})},
},
// UnsortableStructs.
{
// Note: not sorted - SpewKeys is false.
[]reflect.Value{v(unsortableStruct{2}), v(unsortableStruct{1}), v(unsortableStruct{3})},
[]reflect.Value{v(unsortableStruct{2}), v(unsortableStruct{1}), v(unsortableStruct{3})},
},
// Invalid.
{
[]reflect.Value{embedB, embedA, embedC},
[]reflect.Value{embedB, embedA, embedC},
},
}
for _, test := range tests {
spew.SortValues(test.input)
// reflect.DeepEqual cannot really make sense of reflect.Value,
// probably because of all the pointer tricks. For instance,
// v(2.0) != v(2.0) on a 32-bits system. Turn them into interface{}
// instead.
input := getInterfaces(test.input)
expected := getInterfaces(test.expected)
if !reflect.DeepEqual(input, expected) {
t.Errorf("Sort mismatch:\n %v != %v", input, expected)
}
}
cs := spew.ConfigState{DisableMethods: true, SpewKeys: false}
helpTestSortValues(tests, &cs, t)
}
// TestSortValuesWithMethods ensures the sort functionality for relect.Value
// based sorting works as intended when using string methods.
func TestSortValuesWithMethods(t *testing.T) {
v := reflect.ValueOf
a := v("a")
b := v("b")
c := v("c")
tests := []sortTestCase{
// Ints.
{
[]reflect.Value{v(2), v(1), v(3)},
[]reflect.Value{v(1), v(2), v(3)},
},
// Strings.
{
[]reflect.Value{b, a, c},
[]reflect.Value{a, b, c},
},
// SortableStructs.
{
[]reflect.Value{v(sortableStruct{2}), v(sortableStruct{1}), v(sortableStruct{3})},
[]reflect.Value{v(sortableStruct{1}), v(sortableStruct{2}), v(sortableStruct{3})},
},
// UnsortableStructs.
{
// Note: not sorted - SpewKeys is false.
[]reflect.Value{v(unsortableStruct{2}), v(unsortableStruct{1}), v(unsortableStruct{3})},
[]reflect.Value{v(unsortableStruct{2}), v(unsortableStruct{1}), v(unsortableStruct{3})},
},
}
cs := spew.ConfigState{DisableMethods: false, SpewKeys: false}
helpTestSortValues(tests, &cs, t)
}
// TestSortValuesWithSpew ensures the sort functionality for relect.Value
// based sorting works as intended when using spew to stringify keys.
func TestSortValuesWithSpew(t *testing.T) {
v := reflect.ValueOf
a := v("a")
b := v("b")
c := v("c")
tests := []sortTestCase{
// Ints.
{
[]reflect.Value{v(2), v(1), v(3)},
[]reflect.Value{v(1), v(2), v(3)},
},
// Strings.
{
[]reflect.Value{b, a, c},
[]reflect.Value{a, b, c},
},
// SortableStructs.
{
[]reflect.Value{v(sortableStruct{2}), v(sortableStruct{1}), v(sortableStruct{3})},
[]reflect.Value{v(sortableStruct{1}), v(sortableStruct{2}), v(sortableStruct{3})},
},
// UnsortableStructs.
{
[]reflect.Value{v(unsortableStruct{2}), v(unsortableStruct{1}), v(unsortableStruct{3})},
[]reflect.Value{v(unsortableStruct{1}), v(unsortableStruct{2}), v(unsortableStruct{3})},
},
}
cs := spew.ConfigState{DisableMethods: true, SpewKeys: true}
helpTestSortValues(tests, &cs, t)
}

12
spew/config.go
View File

@ -76,10 +76,16 @@ type ConfigState struct {
// SortKeys specifies map keys should be sorted before being printed. Use
// this to have a more deterministic, diffable output. Note that only
// native types (bool, int, uint, floats, uintptr and string) are supported
// with other types sorted according to the reflect.Value.String() output
// which guarantees display stability.
// native types (bool, int, uint, floats, uintptr and string) and types
// that support the error or Stringer interfaces (if methods are
// enabled) are supported, with other types sorted according to the
// reflect.Value.String() output which guarantees display stability.
SortKeys bool
// SpewKeys specifies that, as a last resort attempt, map keys should
// be spewed to strings and sorted by those strings. This is only
// considered if SortKeys is true.
SpewKeys bool
}
// Config is the active configuration of the top-level functions.

12
spew/doc.go
View File

@ -99,9 +99,15 @@ The following configuration options are available:
Specifies map keys should be sorted before being printed. Use
this to have a more deterministic, diffable output. Note that
only native types (bool, int, uint, floats, uintptr and string)
are supported with other types sorted according to the
reflect.Value.String() output which guarantees display stability.
Natural map order is used by default.
and types which implement error or Stringer interfaces are
supported with other types sorted according to the
reflect.Value.String() output which guarantees display
stability. Natural map order is used by default.
* SpewKeys
Specifies that, as a last resort attempt, map keys should be
spewed to strings and sorted by those strings. This is only
considered if SortKeys is true.
Dump Usage

2
spew/dump.go
View File

@ -382,7 +382,7 @@ func (d *dumpState) dump(v reflect.Value) {
numEntries := v.Len()
keys := v.MapKeys()
if d.cs.SortKeys {
sortValues(keys)
sortValues(keys, d.cs)
}
for i, key := range keys {
d.dump(d.unpackValue(key))

37
spew/dump_test.go
View File

@ -64,9 +64,10 @@ package spew_test
import (
"bytes"
"fmt"
"github.com/davecgh/go-spew/spew"
"testing"
"unsafe"
"github.com/davecgh/go-spew/spew"
)
// dumpTest is used to describe a test to be perfomed against the Dump method.
@ -983,4 +984,38 @@ func TestDumpSortedKeys(t *testing.T) {
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sdump(map[stringer]int{"1": 1, "3": 3, "2": 2})
expected = `(map[spew_test.stringer]int) (len=3) {
(spew_test.stringer) (len=1) stringer 1: (int) 1,
(spew_test.stringer) (len=1) stringer 2: (int) 2,
(spew_test.stringer) (len=1) stringer 3: (int) 3
}
`
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sdump(map[pstringer]int{pstringer("1"): 1, pstringer("3"): 3, pstringer("2"): 2})
expected = `(map[spew_test.pstringer]int) (len=3) {
(spew_test.pstringer) (len=1) stringer 1: (int) 1,
(spew_test.pstringer) (len=1) stringer 2: (int) 2,
(spew_test.pstringer) (len=1) stringer 3: (int) 3
}
`
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sdump(map[customError]int{customError(1): 1, customError(3): 3, customError(2): 2})
expected = `(map[spew_test.customError]int) (len=3) {
(spew_test.customError) error: 1: (int) 1,
(spew_test.customError) error: 2: (int) 2,
(spew_test.customError) error: 3: (int) 3
}
`
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
}

2
spew/format.go
View File

@ -309,7 +309,7 @@ func (f *formatState) format(v reflect.Value) {
} else {
keys := v.MapKeys()
if f.cs.SortKeys {
sortValues(keys)
sortValues(keys, f.cs)
}
for i, key := range keys {
if i > 0 {

49
spew/format_test.go
View File

@ -69,9 +69,10 @@ package spew_test
import (
"bytes"
"fmt"
"github.com/davecgh/go-spew/spew"
"testing"
"unsafe"
"github.com/davecgh/go-spew/spew"
)
// formatterTest is used to describe a test to be perfomed against NewFormatter.
@ -1478,6 +1479,22 @@ func TestFormatter(t *testing.T) {
}
}
type testStruct struct {
x int
}
func (ts testStruct) String() string {
return fmt.Sprintf("ts.%d", ts.x)
}
type testStructP struct {
x int
}
func (ts *testStructP) String() string {
return fmt.Sprintf("ts.%d", ts.x)
}
func TestPrintSortedKeys(t *testing.T) {
cfg := spew.ConfigState{SortKeys: true}
s := cfg.Sprint(map[int]string{1: "1", 3: "3", 2: "2"})
@ -1485,4 +1502,34 @@ func TestPrintSortedKeys(t *testing.T) {
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sprint(map[stringer]int{"1": 1, "3": 3, "2": 2})
expected = "map[stringer 1:1 stringer 2:2 stringer 3:3]"
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sprint(map[pstringer]int{pstringer("1"): 1, pstringer("3"): 3, pstringer("2"): 2})
expected = "map[stringer 1:1 stringer 2:2 stringer 3:3]"
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sprint(map[testStruct]int{testStruct{1}: 1, testStruct{3}: 3, testStruct{2}: 2})
expected = "map[ts.1:1 ts.2:2 ts.3:3]"
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sprint(map[testStructP]int{testStructP{1}: 1, testStructP{3}: 3, testStructP{2}: 2})
expected = "map[ts.1:1 ts.2:2 ts.3:3]"
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
s = cfg.Sprint(map[customError]int{customError(1): 1, customError(3): 3, customError(2): 2})
expected = "map[error: 1:1 error: 2:2 error: 3:3]"
if s != expected {
t.Errorf("Sorted keys mismatch:\n %v %v", s, expected)
}
}

4
spew/internal_test.go
View File

@ -151,6 +151,6 @@ func TestAddedReflectValue(t *testing.T) {
// SortValues makes the internal sortValues function available to the test
// package.
func SortValues(values []reflect.Value) {
sortValues(values)
func SortValues(values []reflect.Value, cs *ConfigState) {
sortValues(values, cs)
}