run 'go get -u; make revendor'

Signed-off-by: Stephan Renatus <srenatus@chef.io>

vendor/golang.org/x/text/secure/bidirule/bidirule.go

@@ -155,6 +155,7 @@ func DirectionString(s string) bidi.Direction {
 		e, sz := bidi.LookupString(s[i:])
 		if sz == 0 {
 			i++
+			continue
 		}
 		c := e.Class()
 		if c == bidi.R || c == bidi.AL || c == bidi.AN {
@@ -202,13 +203,6 @@ func (t *Transformer) isRTL() bool {
 	return t.seen&isRTL != 0
 }
 
-func (t *Transformer) isFinal() bool {
-	if !t.isRTL() {
-		return true
-	}
-	return t.state == ruleLTRFinal || t.state == ruleRTLFinal || t.state == ruleInitial
-}
-
 // Reset implements transform.Transformer.
 func (t *Transformer) Reset() { *t = Transformer{} }
 

vendor/golang.org/x/text/secure/bidirule/bidirule10.0.0.go

@@ -0,0 +1,11 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build go1.10
+
+package bidirule
+
+func (t *Transformer) isFinal() bool {
+	return t.state == ruleLTRFinal || t.state == ruleRTLFinal || t.state == ruleInitial
+}

vendor/golang.org/x/text/secure/bidirule/bidirule9.0.0.go

@@ -0,0 +1,14 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !go1.10
+
+package bidirule
+
+func (t *Transformer) isFinal() bool {
+	if !t.isRTL() {
+		return true
+	}
+	return t.state == ruleLTRFinal || t.state == ruleRTLFinal || t.state == ruleInitial
+}

vendor/golang.org/x/text/transform/transform.go

@@ -78,8 +78,8 @@ type SpanningTransformer interface {
 	// considering the error err.
 	//
 	// A nil error means that all input bytes are known to be identical to the
-	// output produced by the Transformer. A nil error can be be returned
-	// regardless of whether atEOF is true. If err is nil, then then n must
+	// output produced by the Transformer. A nil error can be returned
+	// regardless of whether atEOF is true. If err is nil, then n must
 	// equal len(src); the converse is not necessarily true.
 	//
 	// ErrEndOfSpan means that the Transformer output may differ from the
@@ -493,7 +493,7 @@ func (c *chain) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err erro
 	return dstL.n, srcL.p, err
 }
 
-// Deprecated: use runes.Remove instead.
+// Deprecated: Use runes.Remove instead.
 func RemoveFunc(f func(r rune) bool) Transformer {
 	return removeF(f)
 }

vendor/golang.org/x/text/unicode/bidi/bidi.go

@@ -6,7 +6,7 @@
 
 // Package bidi contains functionality for bidirectional text support.
 //
-// See http://www.unicode.org/reports/tr9.
+// See https://www.unicode.org/reports/tr9.
 //
 // NOTE: UNDER CONSTRUCTION. This API may change in backwards incompatible ways
 // and without notice.

vendor/golang.org/x/text/unicode/bidi/bracket.go

@@ -12,7 +12,7 @@ import (
 
 // This file contains a port of the reference implementation of the
 // Bidi Parentheses Algorithm:
-// http://www.unicode.org/Public/PROGRAMS/BidiReferenceJava/BidiPBAReference.java
+// https://www.unicode.org/Public/PROGRAMS/BidiReferenceJava/BidiPBAReference.java
 //
 // The implementation in this file covers definitions BD14-BD16 and rule N0
 // of UAX#9.
@@ -246,7 +246,7 @@ func (p *bracketPairer) getStrongTypeN0(index int) Class {
 // assuming the given embedding direction.
 //
 // It returns ON if no strong type is found. If a single strong type is found,
-// it returns this this type. Otherwise it returns the embedding direction.
+// it returns this type. Otherwise it returns the embedding direction.
 //
 // TODO: use separate type for "strong" directionality.
 func (p *bracketPairer) classifyPairContent(loc bracketPair, dirEmbed Class) Class {

vendor/golang.org/x/text/unicode/bidi/core.go

@@ -7,7 +7,7 @@ package bidi
 import "log"
 
 // This implementation is a port based on the reference implementation found at:
-// http://www.unicode.org/Public/PROGRAMS/BidiReferenceJava/
+// https://www.unicode.org/Public/PROGRAMS/BidiReferenceJava/
 //
 // described in Unicode Bidirectional Algorithm (UAX #9).
 //

vendor/golang.org/x/text/unicode/bidi/gen.go

@@ -26,7 +26,7 @@ func main() {
 }
 
 // bidiClass names and codes taken from class "bc" in
-// http://www.unicode.org/Public/8.0.0/ucd/PropertyValueAliases.txt
+// https://www.unicode.org/Public/8.0.0/ucd/PropertyValueAliases.txt
 var bidiClass = map[string]Class{
 	"AL":  AL,  // ArabicLetter
 	"AN":  AN,  // ArabicNumber
@@ -59,7 +59,7 @@ func genTables() {
 		log.Fatalf("Too many Class constants (%#x > 0x0F).", numClass)
 	}
 	w := gen.NewCodeWriter()
-	defer w.WriteGoFile(*outputFile, "bidi")
+	defer w.WriteVersionedGoFile(*outputFile, "bidi")
 
 	gen.WriteUnicodeVersion(w)
 

vendor/golang.org/x/text/unicode/bidi/gen_ranges.go

@@ -15,7 +15,7 @@ import (
 )
 
 // These tables are hand-extracted from:
-// http://www.unicode.org/Public/8.0.0/ucd/extracted/DerivedBidiClass.txt
+// https://www.unicode.org/Public/8.0.0/ucd/extracted/DerivedBidiClass.txt
 func visitDefaults(fn func(r rune, c Class)) {
 	// first write default values for ranges listed above.
 	visitRunes(fn, AL, []rune{

vendor/golang.org/x/text/unicode/bidi/tables9.0.0.go

@@ -1,5 +1,7 @@
 // Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
 
+// +build !go1.10
+
 package bidi
 
 // UnicodeVersion is the Unicode version from which the tables in this package are derived.

vendor/golang.org/x/text/unicode/norm/composition.go

@@ -33,17 +33,9 @@ const (
 // streamSafe implements the policy of when a CGJ should be inserted.
 type streamSafe uint8
 
-// mkStreamSafe is a shorthand for declaring a streamSafe var and calling
-// first on it.
-func mkStreamSafe(p Properties) streamSafe {
-	return streamSafe(p.nTrailingNonStarters())
-}
-
-// first inserts the first rune of a segment.
+// first inserts the first rune of a segment. It is a faster version of next if
+// it is known p represents the first rune in a segment.
 func (ss *streamSafe) first(p Properties) {
-	if *ss != 0 {
-		panic("!= 0")
-	}
 	*ss = streamSafe(p.nTrailingNonStarters())
 }
 
@@ -66,7 +58,7 @@ func (ss *streamSafe) next(p Properties) ssState {
 	// be a non-starter. Note that it always hold that if nLead > 0 then
 	// nLead == nTrail.
 	if n == 0 {
-		*ss = 0
+		*ss = streamSafe(p.nTrailingNonStarters())
 		return ssStarter
 	}
 	return ssSuccess
@@ -142,7 +134,6 @@ func (rb *reorderBuffer) setFlusher(out []byte, f func(*reorderBuffer) bool) {
 func (rb *reorderBuffer) reset() {
 	rb.nrune = 0
 	rb.nbyte = 0
-	rb.ss = 0
 }
 
 func (rb *reorderBuffer) doFlush() bool {
@@ -257,6 +248,9 @@ func (rb *reorderBuffer) insertUnsafe(src input, i int, info Properties) {
 // It flushes the buffer on each new segment start.
 func (rb *reorderBuffer) insertDecomposed(dcomp []byte) insertErr {
 	rb.tmpBytes.setBytes(dcomp)
+	// As the streamSafe accounting already handles the counting for modifiers,
+	// we don't have to call next. However, we do need to keep the accounting
+	// intact when flushing the buffer.
 	for i := 0; i < len(dcomp); {
 		info := rb.f.info(rb.tmpBytes, i)
 		if info.BoundaryBefore() && rb.nrune > 0 && !rb.doFlush() {
@@ -413,7 +407,7 @@ func decomposeHangul(buf []byte, r rune) int {
 
 // decomposeHangul algorithmically decomposes a Hangul rune into
 // its Jamo components.
-// See http://unicode.org/reports/tr15/#Hangul for details on decomposing Hangul.
+// See https://unicode.org/reports/tr15/#Hangul for details on decomposing Hangul.
 func (rb *reorderBuffer) decomposeHangul(r rune) {
 	r -= hangulBase
 	x := r % jamoTCount
@@ -426,7 +420,7 @@ func (rb *reorderBuffer) decomposeHangul(r rune) {
 }
 
 // combineHangul algorithmically combines Jamo character components into Hangul.
-// See http://unicode.org/reports/tr15/#Hangul for details on combining Hangul.
+// See https://unicode.org/reports/tr15/#Hangul for details on combining Hangul.
 func (rb *reorderBuffer) combineHangul(s, i, k int) {
 	b := rb.rune[:]
 	bn := rb.nrune
@@ -467,6 +461,10 @@ func (rb *reorderBuffer) combineHangul(s, i, k int) {
 // It should only be used to recompose a single segment, as it will not
 // handle alternations between Hangul and non-Hangul characters correctly.
 func (rb *reorderBuffer) compose() {
+	// Lazily load the map used by the combine func below, but do
+	// it outside of the loop.
+	recompMapOnce.Do(buildRecompMap)
+
 	// UAX #15, section X5 , including Corrigendum #5
 	// "In any character sequence beginning with starter S, a character C is
 	//  blocked from S if and only if there is some character B between S

vendor/golang.org/x/text/unicode/norm/forminfo.go

@@ -4,6 +4,8 @@
 
 package norm
 
+import "encoding/binary"
+
 // This file contains Form-specific logic and wrappers for data in tables.go.
 
 // Rune info is stored in a separate trie per composing form. A composing form
@@ -178,6 +180,17 @@ func (p Properties) TrailCCC() uint8 {
 	return ccc[p.tccc]
 }
 
+func buildRecompMap() {
+	recompMap = make(map[uint32]rune, len(recompMapPacked)/8)
+	var buf [8]byte
+	for i := 0; i < len(recompMapPacked); i += 8 {
+		copy(buf[:], recompMapPacked[i:i+8])
+		key := binary.BigEndian.Uint32(buf[:4])
+		val := binary.BigEndian.Uint32(buf[4:])
+		recompMap[key] = rune(val)
+	}
+}
+
 // Recomposition
 // We use 32-bit keys instead of 64-bit for the two codepoint keys.
 // This clips off the bits of three entries, but we know this will not
@@ -186,8 +199,14 @@ func (p Properties) TrailCCC() uint8 {
 // Note that the recomposition map for NFC and NFKC are identical.
 
 // combine returns the combined rune or 0 if it doesn't exist.
+//
+// The caller is responsible for calling
+// recompMapOnce.Do(buildRecompMap) sometime before this is called.
 func combine(a, b rune) rune {
 	key := uint32(uint16(a))<<16 + uint32(uint16(b))
+	if recompMap == nil {
+		panic("caller error") // see func comment
+	}
 	return recompMap[key]
 }
 

vendor/golang.org/x/text/unicode/norm/input.go

@@ -90,16 +90,20 @@ func (in *input) charinfoNFKC(p int) (uint16, int) {
 }
 
 func (in *input) hangul(p int) (r rune) {
+	var size int
 	if in.bytes == nil {
 		if !isHangulString(in.str[p:]) {
 			return 0
 		}
-		r, _ = utf8.DecodeRuneInString(in.str[p:])
+		r, size = utf8.DecodeRuneInString(in.str[p:])
 	} else {
 		if !isHangul(in.bytes[p:]) {
 			return 0
 		}
-		r, _ = utf8.DecodeRune(in.bytes[p:])
+		r, size = utf8.DecodeRune(in.bytes[p:])
+	}
+	if size != hangulUTF8Size {
+		return 0
 	}
 	return r
 }

vendor/golang.org/x/text/unicode/norm/iter.go

@@ -41,6 +41,7 @@ func (i *Iter) Init(f Form, src []byte) {
 	i.next = i.rb.f.nextMain
 	i.asciiF = nextASCIIBytes
 	i.info = i.rb.f.info(i.rb.src, i.p)
+	i.rb.ss.first(i.info)
 }
 
 // InitString initializes i to iterate over src after normalizing it to Form f.
@@ -56,11 +57,12 @@ func (i *Iter) InitString(f Form, src string) {
 	i.next = i.rb.f.nextMain
 	i.asciiF = nextASCIIString
 	i.info = i.rb.f.info(i.rb.src, i.p)
+	i.rb.ss.first(i.info)
 }
 
 // Seek sets the segment to be returned by the next call to Next to start
 // at position p.  It is the responsibility of the caller to set p to the
-// start of a UTF8 rune.
+// start of a segment.
 func (i *Iter) Seek(offset int64, whence int) (int64, error) {
 	var abs int64
 	switch whence {
@@ -84,6 +86,7 @@ func (i *Iter) Seek(offset int64, whence int) (int64, error) {
 	i.multiSeg = nil
 	i.next = i.rb.f.nextMain
 	i.info = i.rb.f.info(i.rb.src, i.p)
+	i.rb.ss.first(i.info)
 	return abs, nil
 }
 
@@ -125,8 +128,9 @@ func (i *Iter) Next() []byte {
 func nextASCIIBytes(i *Iter) []byte {
 	p := i.p + 1
 	if p >= i.rb.nsrc {
+		p0 := i.p
 		i.setDone()
-		return i.rb.src.bytes[i.p:p]
+		return i.rb.src.bytes[p0:p]
 	}
 	if i.rb.src.bytes[p] < utf8.RuneSelf {
 		p0 := i.p
@@ -161,6 +165,7 @@ func nextHangul(i *Iter) []byte {
 	if next >= i.rb.nsrc {
 		i.setDone()
 	} else if i.rb.src.hangul(next) == 0 {
+		i.rb.ss.next(i.info)
 		i.info = i.rb.f.info(i.rb.src, i.p)
 		i.next = i.rb.f.nextMain
 		return i.next(i)
@@ -204,12 +209,10 @@ func nextMultiNorm(i *Iter) []byte {
 		if info.BoundaryBefore() {
 			i.rb.compose()
 			seg := i.buf[:i.rb.flushCopy(i.buf[:])]
-			i.rb.ss.first(info)
 			i.rb.insertUnsafe(input{bytes: d}, j, info)
 			i.multiSeg = d[j+int(info.size):]
 			return seg
 		}
-		i.rb.ss.next(info)
 		i.rb.insertUnsafe(input{bytes: d}, j, info)
 		j += int(info.size)
 	}
@@ -222,9 +225,9 @@ func nextMultiNorm(i *Iter) []byte {
 func nextDecomposed(i *Iter) (next []byte) {
 	outp := 0
 	inCopyStart, outCopyStart := i.p, 0
-	ss := mkStreamSafe(i.info)
 	for {
 		if sz := int(i.info.size); sz <= 1 {
+			i.rb.ss = 0
 			p := i.p
 			i.p++ // ASCII or illegal byte.  Either way, advance by 1.
 			if i.p >= i.rb.nsrc {
@@ -243,6 +246,8 @@ func nextDecomposed(i *Iter) (next []byte) {
 			p := outp + len(d)
 			if outp > 0 {
 				i.rb.src.copySlice(i.buf[outCopyStart:], inCopyStart, i.p)
+				// TODO: this condition should not be possible, but we leave it
+				// in for defensive purposes.
 				if p > len(i.buf) {
 					return i.buf[:outp]
 				}
@@ -266,7 +271,7 @@ func nextDecomposed(i *Iter) (next []byte) {
 			} else {
 				i.info = i.rb.f.info(i.rb.src, i.p)
 			}
-			switch ss.next(i.info) {
+			switch i.rb.ss.next(i.info) {
 			case ssOverflow:
 				i.next = nextCGJDecompose
 				fallthrough
@@ -309,7 +314,7 @@ func nextDecomposed(i *Iter) (next []byte) {
 		}
 		prevCC := i.info.tccc
 		i.info = i.rb.f.info(i.rb.src, i.p)
-		if v := ss.next(i.info); v == ssStarter {
+		if v := i.rb.ss.next(i.info); v == ssStarter {
 			break
 		} else if v == ssOverflow {
 			i.next = nextCGJDecompose
@@ -335,10 +340,6 @@ doNorm:
 
 func doNormDecomposed(i *Iter) []byte {
 	for {
-		if s := i.rb.ss.next(i.info); s == ssOverflow {
-			i.next = nextCGJDecompose
-			break
-		}
 		i.rb.insertUnsafe(i.rb.src, i.p, i.info)
 		if i.p += int(i.info.size); i.p >= i.rb.nsrc {
 			i.setDone()
@@ -348,6 +349,10 @@ func doNormDecomposed(i *Iter) []byte {
 		if i.info.ccc == 0 {
 			break
 		}
+		if s := i.rb.ss.next(i.info); s == ssOverflow {
+			i.next = nextCGJDecompose
+			break
+		}
 	}
 	// new segment or too many combining characters: exit normalization
 	return i.buf[:i.rb.flushCopy(i.buf[:])]
@@ -357,6 +362,7 @@ func nextCGJDecompose(i *Iter) []byte {
 	i.rb.ss = 0
 	i.rb.insertCGJ()
 	i.next = nextDecomposed
+	i.rb.ss.first(i.info)
 	buf := doNormDecomposed(i)
 	return buf
 }
@@ -365,7 +371,6 @@ func nextCGJDecompose(i *Iter) []byte {
 func nextComposed(i *Iter) []byte {
 	outp, startp := 0, i.p
 	var prevCC uint8
-	ss := mkStreamSafe(i.info)
 	for {
 		if !i.info.isYesC() {
 			goto doNorm
@@ -385,11 +390,12 @@ func nextComposed(i *Iter) []byte {
 			i.setDone()
 			break
 		} else if i.rb.src._byte(i.p) < utf8.RuneSelf {
+			i.rb.ss = 0
 			i.next = i.asciiF
 			break
 		}
 		i.info = i.rb.f.info(i.rb.src, i.p)
-		if v := ss.next(i.info); v == ssStarter {
+		if v := i.rb.ss.next(i.info); v == ssStarter {
 			break
 		} else if v == ssOverflow {
 			i.next = nextCGJCompose
@@ -401,8 +407,10 @@ func nextComposed(i *Iter) []byte {
 	}
 	return i.returnSlice(startp, i.p)
 doNorm:
+	// reset to start position
 	i.p = startp
 	i.info = i.rb.f.info(i.rb.src, i.p)
+	i.rb.ss.first(i.info)
 	if i.info.multiSegment() {
 		d := i.info.Decomposition()
 		info := i.rb.f.info(input{bytes: d}, 0)

vendor/golang.org/x/text/unicode/norm/maketables.go

@@ -12,6 +12,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/binary"
 	"flag"
 	"fmt"
 	"io"
@@ -261,7 +262,7 @@ func compactCCC() {
 
 // CompositionExclusions.txt has form:
 // 0958    # ...
-// See http://unicode.org/reports/tr44/ for full explanation
+// See https://unicode.org/reports/tr44/ for full explanation
 func loadCompositionExclusions() {
 	f := gen.OpenUCDFile("CompositionExclusions.txt")
 	defer f.Close()
@@ -735,6 +736,8 @@ func makeTables() {
 			max = n
 		}
 	}
+	fmt.Fprintln(w, `import "sync"`)
+	fmt.Fprintln(w)
 
 	fmt.Fprintln(w, "const (")
 	fmt.Fprintln(w, "\t// Version is the Unicode edition from which the tables are derived.")
@@ -782,20 +785,27 @@ func makeTables() {
 		sz := nrentries * 8
 		size += sz
 		fmt.Fprintf(w, "// recompMap: %d bytes (entries only)\n", sz)
-		fmt.Fprintln(w, "var recompMap = map[uint32]rune{")
+		fmt.Fprintln(w, "var recompMap map[uint32]rune")
+		fmt.Fprintln(w, "var recompMapOnce sync.Once\n")
+		fmt.Fprintln(w, `const recompMapPacked = "" +`)
+		var buf [8]byte
 		for i, c := range chars {
 			f := c.forms[FCanonical]
 			d := f.decomp
 			if !f.isOneWay && len(d) > 0 {
 				key := uint32(uint16(d[0]))<<16 + uint32(uint16(d[1]))
-				fmt.Fprintf(w, "0x%.8X: 0x%.4X,\n", key, i)
+				binary.BigEndian.PutUint32(buf[:4], key)
+				binary.BigEndian.PutUint32(buf[4:], uint32(i))
+				fmt.Fprintf(w, "\t\t%q + // 0x%.8X: 0x%.8X\n", string(buf[:]), key, uint32(i))
 			}
 		}
-		fmt.Fprintf(w, "}\n\n")
+		// hack so we don't have to special case the trailing plus sign
+		fmt.Fprintf(w, `	""`)
+		fmt.Fprintln(w)
 	}
 
 	fmt.Fprintf(w, "// Total size of tables: %dKB (%d bytes)\n", (size+512)/1024, size)
-	gen.WriteGoFile("tables.go", "norm", w.Bytes())
+	gen.WriteVersionedGoFile("tables.go", "norm", w.Bytes())
 }
 
 func printChars() {
@@ -857,7 +867,7 @@ func verifyComputed() {
 // DerivedNormalizationProps.txt has form:
 // 00C0..00C5    ; NFD_QC; N # ...
 // 0374          ; NFD_QC; N # ...
-// See http://unicode.org/reports/tr44/ for full explanation
+// See https://unicode.org/reports/tr44/ for full explanation
 func testDerived() {
 	f := gen.OpenUCDFile("DerivedNormalizationProps.txt")
 	defer f.Close()
@@ -972,5 +982,5 @@ func printTestdata() {
 		}
 	}
 	fmt.Fprintln(w, "}")
-	gen.WriteGoFile("data_test.go", "norm", w.Bytes())
+	gen.WriteVersionedGoFile("data_test.go", "norm", w.Bytes())
 }

vendor/golang.org/x/text/unicode/norm/normalize.go

@@ -29,8 +29,8 @@ import (
 // proceed independently on both sides:
 //   f(x) == append(f(x[0:n]), f(x[n:])...)
 //
-// References: http://unicode.org/reports/tr15/ and
-// http://unicode.org/notes/tn5/.
+// References: https://unicode.org/reports/tr15/ and
+// https://unicode.org/notes/tn5/.
 type Form int
 
 const (
@@ -324,7 +324,6 @@ func (f *formInfo) quickSpan(src input, i, end int, atEOF bool) (n int, ok bool)
 		// have an overflow for runes that are starters (e.g. with U+FF9E).
 		switch ss.next(info) {
 		case ssStarter:
-			ss.first(info)
 			lastSegStart = i
 		case ssOverflow:
 			return lastSegStart, false
@@ -441,6 +440,8 @@ func (f Form) nextBoundary(src input, nsrc int, atEOF bool) int {
 			}
 			return -1
 		}
+		// TODO: Using streamSafe to determine the boundary isn't the same as
+		// using BoundaryBefore. Determine which should be used.
 		if s := ss.next(info); s != ssSuccess {
 			return i
 		}
@@ -505,15 +506,14 @@ func decomposeSegment(rb *reorderBuffer, sp int, atEOF bool) int {
 	if info.size == 0 {
 		return 0
 	}
-	if rb.nrune > 0 {
-		if s := rb.ss.next(info); s == ssStarter {
-			goto end
-		} else if s == ssOverflow {
-			rb.insertCGJ()
+	if s := rb.ss.next(info); s == ssStarter {
+		// TODO: this could be removed if we don't support merging.
+		if rb.nrune > 0 {
 			goto end
 		}
-	} else {
-		rb.ss.first(info)
+	} else if s == ssOverflow {
+		rb.insertCGJ()
+		goto end
 	}
 	if err := rb.insertFlush(rb.src, sp, info); err != iSuccess {
 		return int(err)

vendor/golang.org/x/text/unicode/norm/readwriter.go

@@ -60,8 +60,8 @@ func (w *normWriter) Close() error {
 }
 
 // Writer returns a new writer that implements Write(b)
-// by writing f(b) to w.  The returned writer may use an
-// an internal buffer to maintain state across Write calls.
+// by writing f(b) to w. The returned writer may use an
+// internal buffer to maintain state across Write calls.
 // Calling its Close method writes any buffered data to w.
 func (f Form) Writer(w io.Writer) io.WriteCloser {
 	wr := &normWriter{rb: reorderBuffer{}, w: w}

vendor/golang.org/x/text/unicode/norm/transform.go

@@ -18,7 +18,6 @@ func (Form) Reset() {}
 // Users should either catch ErrShortDst and allow dst to grow or have dst be at
 // least of size MaxTransformChunkSize to be guaranteed of progress.
 func (f Form) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
-	n := 0
 	// Cap the maximum number of src bytes to check.
 	b := src
 	eof := atEOF
@@ -27,20 +26,21 @@ func (f Form) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error)
 		eof = false
 		b = b[:ns]
 	}
-	i, ok := formTable[f].quickSpan(inputBytes(b), n, len(b), eof)
-	n += copy(dst[n:], b[n:i])
+	i, ok := formTable[f].quickSpan(inputBytes(b), 0, len(b), eof)
+	n := copy(dst, b[:i])
 	if !ok {
 		nDst, nSrc, err = f.transform(dst[n:], src[n:], atEOF)
 		return nDst + n, nSrc + n, err
 	}
-	if n < len(src) && !atEOF {
+
+	if err == nil && n < len(src) && !atEOF {
 		err = transform.ErrShortSrc
 	}
 	return n, n, err
 }
 
 func flushTransform(rb *reorderBuffer) bool {
-	// Write out (must fully fit in dst, or else it is a ErrShortDst).
+	// Write out (must fully fit in dst, or else it is an ErrShortDst).
 	if len(rb.out) < rb.nrune*utf8.UTFMax {
 		return false
 	}
@@ -79,7 +79,7 @@ func (f Form) transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error)
 		nSrc += n
 		nDst += n
 		if ok {
-			if n < rb.nsrc && !atEOF {
+			if err == nil && n < rb.nsrc && !atEOF {
 				err = transform.ErrShortSrc
 			}
 			return nDst, nSrc, err