diff --git a/cmp/compare_test.go b/cmp/compare_test.go index b34530b..ba39bde 100644 --- a/cmp/compare_test.go +++ b/cmp/compare_test.go @@ -1133,6 +1133,19 @@ func reporterTests() []test { y: "aaa\nbbb\nccc \nddd\neee\nfff\nggg\nhhh\niii\njjj\nkkk\nlll\nmmm\nnnn\nooo\nppp\nqqq\nrrr\nsss\nttt\nuuu\nvvv\nwww\nxxx\nyyy\nzzz\n", wantEqual: false, reason: "avoid triple-quote syntax due to visual equivalence of differences", + }, { + label: label + "/TripleQuoteStringer", + x: []fmt.Stringer{ + bytes.NewBuffer([]byte("package main\n\nimport (\n\t\"fmt\"\n)\n\nfunc main() {\n\tfmt.Println(\"Hello, playground\")\n}\n")), + bytes.NewBuffer([]byte("package main\n\nimport (\n\t\"fmt\"\n\t\"math/rand\"\n)\n\nfunc main() {\n\tfmt.Println(\"My favorite number is\", rand.Intn(10))\n}\n")), + }, + y: []fmt.Stringer{ + bytes.NewBuffer([]byte("package main\n\nimport (\n\t\"fmt\"\n)\n\nfunc main() {\n\tfmt.Println(\"Hello, playground\")\n}\n")), + bytes.NewBuffer([]byte("package main\n\nimport (\n\t\"fmt\"\n\t\"math\"\n)\n\nfunc main() {\n\tfmt.Printf(\"Now you have %g problems.\\n\", math.Sqrt(7))\n}\n")), + }, + opts: []cmp.Option{cmp.Comparer(func(x, y fmt.Stringer) bool { return x.String() == y.String() })}, + wantEqual: false, + reason: "multi-line String output should be formatted with triple quote", }, { label: label + "/LimitMaximumBytesDiffs", x: []byte("\xcd====\x06\x1f\xc2\xcc\xc2-S=====\x1d\xdfa\xae\x98\x9fH======ǰ\xb7=======\xef====:\\\x94\xe6J\xc7=====\xb4======\n\n\xf7\x94===========\xf2\x9c\xc0f=====4\xf6\xf1\xc3\x17\x82======n\x16`\x91D\xc6\x06=======\x1cE====.===========\xc4\x18=======\x8a\x8d\x0e====\x87\xb1\xa5\x8e\xc3=====z\x0f1\xaeU======G,=======5\xe75\xee\x82\xf4\xce====\x11r===========\xaf]=======z\x05\xb3\x91\x88%\xd2====\n1\x89=====i\xb7\x055\xe6\x81\xd2=============\x883=@̾====\x14\x05\x96%^t\x04=====\xe7Ȉ\x90\x1d============="), diff --git a/cmp/report_reflect.go b/cmp/report_reflect.go index 28e0e92..786f671 100644 --- a/cmp/report_reflect.go +++ b/cmp/report_reflect.go @@ -5,6 +5,7 @@ package cmp import ( + "bytes" "fmt" "reflect" "strconv" @@ -138,14 +139,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, } }() if prefix != "" { - maxLen := len(strVal) - if opts.LimitVerbosity { - maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc... - } - if len(strVal) > maxLen+len(textEllipsis) { - return textLine(prefix + formatString(strVal[:maxLen]) + string(textEllipsis)) - } - return textLine(prefix + formatString(strVal)) + return opts.formatString(prefix, strVal) } } } @@ -177,14 +171,7 @@ func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, case reflect.Complex64, reflect.Complex128: return textLine(fmt.Sprint(v.Complex())) case reflect.String: - maxLen := v.Len() - if opts.LimitVerbosity { - maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc... - } - if v.Len() > maxLen+len(textEllipsis) { - return textLine(formatString(v.String()[:maxLen]) + string(textEllipsis)) - } - return textLine(formatString(v.String())) + return opts.formatString("", v.String()) case reflect.UnsafePointer, reflect.Chan, reflect.Func: return textLine(formatPointer(value.PointerOf(v), true)) case reflect.Struct: @@ -216,6 +203,17 @@ func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, if v.IsNil() { return textNil } + + // Check whether this is a []byte of text data. + if t.Elem() == reflect.TypeOf(byte(0)) { + b := v.Bytes() + isPrintSpace := func(r rune) bool { return unicode.IsPrint(r) && unicode.IsSpace(r) } + if len(b) > 0 && utf8.Valid(b) && len(bytes.TrimFunc(b, isPrintSpace)) == 0 { + out = opts.formatString("", string(b)) + return opts.WithTypeMode(emitType).FormatType(t, out) + } + } + fallthrough case reflect.Array: maxLen := v.Len() @@ -301,6 +299,49 @@ func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, } } +func (opts formatOptions) formatString(prefix, s string) textNode { + maxLen := len(s) + maxLines := strings.Count(s, "\n") + 1 + if opts.LimitVerbosity { + maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc... + maxLines = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc... + } + + // For multiline strings, use the triple-quote syntax, + // but only use it when printing removed or inserted nodes since + // we only want the extra verbosity for those cases. + lines := strings.Split(strings.TrimSuffix(s, "\n"), "\n") + isTripleQuoted := len(lines) >= 4 && (opts.DiffMode == '-' || opts.DiffMode == '+') + for i := 0; i < len(lines) && isTripleQuoted; i++ { + lines[i] = strings.TrimPrefix(strings.TrimSuffix(lines[i], "\r"), "\r") // trim leading/trailing carriage returns for legacy Windows endline support + isPrintable := func(r rune) bool { + return unicode.IsPrint(r) || r == '\t' // specially treat tab as printable + } + line := lines[i] + isTripleQuoted = !strings.HasPrefix(strings.TrimPrefix(line, prefix), `"""`) && !strings.HasPrefix(line, "...") && strings.TrimFunc(line, isPrintable) == "" && len(line) <= maxLen + } + if isTripleQuoted { + var list textList + list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true}) + for i, line := range lines { + if numElided := len(lines) - i; i == maxLines-1 && numElided > 1 { + comment := commentString(fmt.Sprintf("%d elided lines", numElided)) + list = append(list, textRecord{Diff: opts.DiffMode, Value: textEllipsis, ElideComma: true, Comment: comment}) + break + } + list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(line), ElideComma: true}) + } + list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true}) + return &textWrap{Prefix: "(", Value: list, Suffix: ")"} + } + + // Format the string as a single-line quoted string. + if len(s) > maxLen+len(textEllipsis) { + return textLine(prefix + formatString(s[:maxLen]) + string(textEllipsis)) + } + return textLine(prefix + formatString(s)) +} + // formatMapKey formats v as if it were a map key. // The result is guaranteed to be a single line. func formatMapKey(v reflect.Value, disambiguate bool, ptrs *pointerReferences) string { diff --git a/cmp/testdata/diffs b/cmp/testdata/diffs index 05fa3fd..dee035d 100644 --- a/cmp/testdata/diffs +++ b/cmp/testdata/diffs @@ -730,6 +730,39 @@ ... // 7 identical lines }, "\n") >>> TestDiff/Reporter/AvoidTripleQuoteIdenticalWhitespace +<<< TestDiff/Reporter/TripleQuoteStringer + []fmt.Stringer{ + s"package main\n\nimport (\n\t\"fmt\"\n)\n\nfunc main() {\n\tfmt.Println(\"Hel"..., +- ( +- s""" +- package main +- +- import ( +- "fmt" +- "math/rand" +- ) +- +- func main() { +- fmt.Println("My favorite number is", rand.Intn(10)) +- } +- s""" +- ), ++ ( ++ s""" ++ package main ++ ++ import ( ++ "fmt" ++ "math" ++ ) ++ ++ func main() { ++ fmt.Printf("Now you have %g problems.\n", math.Sqrt(7)) ++ } ++ s""" ++ ), + } +>>> TestDiff/Reporter/TripleQuoteStringer <<< TestDiff/Reporter/LimitMaximumBytesDiffs []uint8{ - 0xcd, 0x3d, 0x3d, 0x3d, 0x3d, 0x06, 0x1f, 0xc2, 0xcc, 0xc2, 0x2d, 0x53, // -|.====.....-S|