work on KVBuffer exhausted semantics

http/httphi/exchange_test.go

@@ -1267,9 +1267,9 @@ func TestHandleBrowserSizedRequest(t *testing.T) {
 	sm.Reset(1)
 	sm.Handle("GET /echo", func(exch *Exchange) {
 		gotMode = string(exch.RequestHeader("X-Mode"))
-		exch.RequestHeaderRaw().ForEach(func(key, value []byte) error {
+		exch.RequestHeaderRaw().ForEach(func(key, value []byte) bool {
 			fields++
-			return nil
+			return true
 		})
 	})
 	conn := newConn(request)
@@ -1321,7 +1321,7 @@ func TestHandleRequestTooLargeAnswers431(t *testing.T) {
 			// Room for the fields, but not for the bytes they arrive in.
 			name:    "more bytes than the buffer holds",
 			cfg:     ExchangeConfig{RawBuf: make([]byte, 2*1024), RequestBufferLim: 1024, NumHeaderKVCap: 1024, NoRequestBufferGrowth: true},
-			wantErr: httpraw.ErrSmallHeaderBuffer,
+			wantErr: httpraw.ErrBufferExhausted,
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {

http/httphi/mux.go

@@ -79,7 +79,7 @@ func Handle(exch *Exchange, mux Mux, backoff lneto.BackoffStrategy) error {
 }
 
 func (exch *Exchange) handleError(err error) {
-	if err == httpraw.ErrHeaderTooMany || err == httpraw.ErrSmallHeaderBuffer || exch.reqHdr.BufferFree() == 0 {
+	if err == httpraw.ErrHeaderTooMany || err == httpraw.ErrBufferExhausted || exch.reqHdr.BufferFree() == 0 {
 		// The peer is owed an answer: no larger buffer is coming, so
 		// say so instead of dropping the connection, RFC 6585 5.
 		exch.StageHeader("Content-Length", "0")

http/httpraw/cookie.go

@@ -55,7 +55,7 @@ func (c *Cookie) Parse() error {
 			break
 		}
 		if !c.kv.setInternal(k, v) {
-			return errOOM
+			return ErrBufferExhausted
 		}
 
 		off += n

http/httpraw/form.go

@@ -35,7 +35,7 @@ func (f *Form) Parse() error {
 	key, value, rest := NextQueryPair(f.kv.buf)
 	for key != nil {
 		if !f.kv.setInternal(key, value) {
-			return errOOM
+			return ErrBufferExhausted
 		}
 		key, value, rest = NextQueryPair(rest)
 	}

http/httpraw/header.go

@@ -234,12 +234,7 @@ func (h *Header) SetInt(key string, value int64, base int) {
 	if base < 2 || base > 36 {
 		return // strconv.AppendInt only supports base 2..36.
 	}
-	useKv := h.takeReusableSlot(key)
-	if useKv == nil {
-		h.appendHeaderInt(key, value, base)
-	} else {
-		useKv.value = h.reuseOrAppendInt(useKv.value, value, base)
-	}
+	h.hbuf.kv.SetInt(key, value, base)
 }
 
 // Set sets a key-value pair in the HTTP header.
@@ -249,9 +244,9 @@ func (h *Header) Set(key, value string) (enoughSpace bool) {
 
 	// useKv := h.takeReusableSlot(key)
 	// if useKv == nil {
-	// 	h.appendHeader(key, value)
+	// 	h.hbuf.kv.appendPair(key, value)
 	// } else {
-	// 	useKv.value = h.reuseOrAppend(useKv.value, value)
+	// 	useKv.value = h.hbuf.kv.reuseOrAppend(useKv.value, value)
 	// }
 }
 
@@ -355,7 +350,7 @@ func (h *Header) ContentLength() (_ int64, present bool, _ error) {
 
 // Add adds a new key-value pair to the HTTP header. Calling Add mangles the buffer.
 func (h *Header) Add(key, value string) {
-	h.appendHeader(key, value)
+	h.hbuf.kv.appendPair(key, value)
 }
 
 // Method returns HTTP request method.
@@ -365,12 +360,12 @@ func (h *Header) Method() []byte {
 
 // SetMethod sets the request header's method.
 func (h *Header) SetMethod(method string) {
-	h.method = h.reuseOrAppend(h.method, method)
+	h.method = h.hbuf.kv.reuseOrAppend(h.method, method)
 }
 
 // SetRequestTarget sets request-target (URI) for the first HTTP request line.
 func (h *Header) SetRequestTarget(requestTarget string) {
-	h.requestTarget = h.reuseOrAppend(h.requestTarget, requestTarget)
+	h.requestTarget = h.hbuf.kv.reuseOrAppend(h.requestTarget, requestTarget)
 }
 
 // RequestTarget returns a view of the request-target (URI) of the first HTTP request line.
@@ -442,7 +437,7 @@ func (h *Header) Protocol() []byte {
 
 // SetProtocol sets the request header's protocol. Usually "HTTP/1.1".
 func (h *Header) SetProtocol(protocol string) {
-	h.proto = h.reuseOrAppend(h.proto, protocol)
+	h.proto = h.hbuf.kv.reuseOrAppend(h.proto, protocol)
 }
 
 // Status returns the response header's status code and status text. i.e: "200" "OK".
@@ -456,15 +451,15 @@ func (h *Header) Status() (code, statusText []byte) {
 // SetStatus sets the response header's status code and status text. i.e: "200" "OK".
 func (h *Header) SetStatus(code, statusText string) {
 	h.hbuf.kv.flags |= FlagStatusSet
-	h.statusCode = h.reuseOrAppend(h.statusCode, code)
-	h.statusText = h.reuseOrAppend(h.statusText, statusText)
+	h.statusCode = h.hbuf.kv.reuseOrAppend(h.statusCode, code)
+	h.statusText = h.hbuf.kv.reuseOrAppend(h.statusText, statusText)
 }
 
 // SetStatusInt is identical to [Header.SetStatus] but performs integer to text conversion for status code.
 func (h *Header) SetStatusInt(code int64, statusText string) {
 	h.hbuf.kv.flags |= FlagStatusSet
-	h.statusCode = h.reuseOrAppendInt(h.statusCode, code, 10)
-	h.statusText = h.reuseOrAppend(h.statusText, statusText)
+	h.statusCode = h.hbuf.kv.reuseOrAppendInt(h.statusCode, code, 10)
+	h.statusText = h.hbuf.kv.reuseOrAppend(h.statusText, statusText)
 }
 
 func (h *Header) getNonEmptyValue(s headerSlice) []byte {
@@ -478,7 +473,7 @@ func (h *Header) getNonEmptyValue(s headerSlice) []byte {
 func (h *Header) AppendRequest(dst []byte) ([]byte, error) {
 	proto := h.Protocol()
 	if h.hbuf.kv.flags.HasAny(flagOOMReached) {
-		return dst, errOOM
+		return dst, ErrBufferExhausted
 	} else if h.requestTarget.len == 0 || h.method.len == 0 {
 		return dst, errNeedMethodURI
 	} else if len(proto) == 0 {
@@ -518,7 +513,7 @@ func (h *Header) AppendResponse(dst []byte) ([]byte, error) {
 func (h *Header) AppendResponseNoHeaders(dst []byte) ([]byte, error) {
 	proto := h.Protocol()
 	if h.hbuf.kv.flags.HasAny(flagOOMReached) {
-		return dst, errOOM
+		return dst, ErrBufferExhausted
 	} else if h.statusCode.len == 0 || h.statusText.len == 0 {
 		return dst, errBadStatusCodeTxt
 	} else if len(proto) == 0 {

http/httpraw/header_test.go

@@ -473,7 +473,7 @@ func TestHeader_SplitBeforeColonStillParses(t *testing.T) {
 
 	var h Header
 	h.Reset(nil, numHeaderCapacity)
-	if _, err := h.ReadFromBytes([]byte(part1)); err != nil {
+	if err := h.ReadFromBytes([]byte(part1)); err != nil {
 		t.Fatal(err)
 	}
 	needMore, err := h.TryParse(false)
@@ -484,7 +484,7 @@ func TestHeader_SplitBeforeColonStillParses(t *testing.T) {
 		t.Fatal("want needMoreData=true after partial input")
 	}
 
-	if _, err := h.ReadFromBytes([]byte(part2)); err != nil {
+	if err := h.ReadFromBytes([]byte(part2)); err != nil {
 		t.Fatal(err)
 	}
 	needMore, err = h.TryParse(false)

http/httpraw/kvbuffer.go

@@ -33,36 +33,34 @@ func (mb *KVBuffer) discardKVs() { mb.kvs = mb.kvs[:0] }
 func (mb *KVBuffer) BufferGrowthEnabled() bool { return !mb.flags.HasAny(flagNoBufferGrow) }
 
 func (mb *KVBuffer) ReadFromBytes(buf []byte) error {
-	if mb.flags.HasAny(flagMangledBuffer) {
+	if len(buf) == 0 {
+		return io.ErrNoProgress // Nothing handed over, not a buffer problem.
+	} else if mb.flags.HasAny(flagMangledBuffer) {
 		return errMangledBuffer
 	} else if len(buf)+cap(mb.buf) > maxBufLen {
-		return errOOM
+		return ErrBufferExhausted
 	}
 	free := mb.free()
 	if len(buf) > free && !mb.BufferGrowthEnabled() {
-		return errOOM
+		return ErrBufferExhausted
 	}
 	mb.buf = append(mb.buf, buf...)
 	return nil
 }
 
 func (mb *KVBuffer) ReadLimited(r io.Reader, limit int) (int, error) {
-	if mb.flags.HasAny(flagMangledBuffer) {
+	free := mb.free()
+	growthEnabled := mb.BufferGrowthEnabled()
+	if !growthEnabled && (free == 0 || free < limit) || len(mb.buf) >= maxBufLen {
+		return 0, ErrBufferExhausted
+	} else if mb.flags.HasAny(flagMangledBuffer) {
 		return 0, errMangledBuffer
 	} else if mb.flags.HasAny(flagReaderEOF) {
 		return 0, io.EOF
 	} else if limit <= 0 {
 		return 0, io.ErrNoProgress
-	} else if len(mb.buf) >= maxBufLen {
-		return 0, errOOM
-	}
-	free := mb.free()
-	if limit > free {
-		if !mb.BufferGrowthEnabled() {
-			return 0, errOOM
-		}
-		mb.buf = slices.Grow(mb.buf, limit)
 	}
+	mb.buf = slices.Grow(mb.buf, limit)
 	n, err := r.Read(mb.buf[len(mb.buf):min(len(mb.buf)+limit, maxBufLen)])
 	mb.buf = mb.buf[:len(mb.buf)+n]
 	if err != nil {
@@ -140,6 +138,37 @@ func (mb *KVBuffer) Add(key, value string) (enoughSpace bool) {
 // appended with [KVBuffer.Add] and the invalidated regions are stranded, since
 // nothing here compacts the buffer.
 func (mb *KVBuffer) Set(key, value string) (enoughSpace bool) {
+	reuse := mb.takeReusableSlot(key, len(key), len(value))
+	if reuse < 0 {
+		return mb.Add(key, value)
+	}
+	mb.overwriteAt(reuse, key, value)
+	return true
+}
+
+// SetInt is [KVBuffer.Set]'s integer counterpart. It formats value straight into
+// the slot it reuses, so overwriting a pair never allocates.
+func (mb *KVBuffer) SetInt(key string, value int64, base int) (enoughSpace bool) {
+	reuse := mb.takeReusableSlot(key, len(key), internal.IntLen(value, base))
+	if reuse < 0 {
+		return mb.appendPairInt(key, value, base)
+	}
+	mb.flags |= flagMangledBuffer
+	kv := &mb.kvs[reuse]
+	copy(mb.buf[kv.key.start:], key)
+	kv.key.len = tokint(len(key))
+	// The slot was picked to hold keyLen/valueLen, so AppendInt writes inside
+	// buf and never grows a new backing array.
+	v := strconv.AppendInt(mb.buf[kv.value.start:kv.value.start], value, base)
+	kv.value.len = tokint(len(v))
+	return true
+}
+
+// takeReusableSlot invalidates every pair matching key except the smallest one
+// whose key and value regions hold keyLen and valueLen bytes, whose index it
+// returns. It returns -1 when no surviving slot fits, meaning the caller must
+// append instead.
+func (mb *KVBuffer) takeReusableSlot(key string, keyLen, valueLen int) int {
 	reuse := -1
 	for i := range mb.kvs {
 		kv := &mb.kvs[i]
@@ -147,9 +176,9 @@ func (mb *KVBuffer) Set(key, value string) (enoughSpace bool) {
 			continue
 		}
 		// A valueless pair holds no value region, so reusing one would write the
-		// value over byte 0. Let it fall through to Add, which gives the pair a
-		// real region and keeps "ok" distinct from "ok=".
-		fits := kv.HasValue() && int(kv.key.len) >= len(key) && int(kv.value.len) >= len(value)
+		// value over byte 0. Let it fall through to the caller's append, which
+		// gives the pair a real region and keeps "ok" distinct from "ok=".
+		fits := kv.HasValue() && int(kv.key.len) >= keyLen && int(kv.value.len) >= valueLen
 		if fits && (reuse < 0 || kv.size() < mb.kvs[reuse].size()) {
 			if reuse >= 0 {
 				mb.kvs[reuse].invalidate() // Superseded by a tighter fit.
@@ -159,11 +188,7 @@ func (mb *KVBuffer) Set(key, value string) (enoughSpace bool) {
 		}
 		kv.invalidate()
 	}
-	if reuse < 0 {
-		return mb.Add(key, value)
-	}
-	mb.overwriteAt(reuse, key, value)
-	return true
+	return reuse
 }
 
 // overwriteAt writes key and value over the regions pair i already owns. The
@@ -223,24 +248,6 @@ func (mb *KVBuffer) getIdx(key string) int {
 	return -1
 }
 
-func (mb *KVBuffer) getInvalidIdx() int {
-	for i, kv := range mb.kvs {
-		if !kv.isValid() {
-			return i
-		}
-	}
-	return -1
-}
-
-func (mb *KVBuffer) getInvalidOrKeyIdx(key string) int {
-	for i, kv := range mb.kvs {
-		if !kv.isValid() || key == b2s(mb.musttoken(kv.key)) {
-			return i
-		}
-	}
-	return -1
-}
-
 // reserve ensures need free bytes are available in the buffer, growing it when
 // permitted. It accounts for the byte-0 reservation on an empty buffer (see
 // mustAppendSlice). It returns false and sets flagOOMReached when the space
@@ -313,6 +320,51 @@ func (hb *KVBuffer) mustAppendInt(value int64, base int) headerSlice {
 	return hb.slice(hb.buf[L : L+len(v)])
 }
 
+// reuseOrAppend writes value over tok's slot when it fits there, avoiding any
+// buffer growth; otherwise it appends a fresh slot.
+func (mb *KVBuffer) reuseOrAppend(tok headerSlice, value string) headerSlice {
+	if tok.len > tokint(len(value)) {
+		copy(mb.musttoken(tok), value)
+		tok.len = tokint(len(value))
+		return tok
+	}
+	return mb.appendSlice(value)
+}
+
+// appendSlice reserves space (growing or flagging OOM) and appends value as a
+// new slot.
+func (mb *KVBuffer) appendSlice(value string) headerSlice {
+	debuglog("http:appendslice:start")
+	if !mb.reserve(len(value)) {
+		return headerSlice{} // Drop and flag OOM; never panic.
+	}
+	mb.flags |= flagMangledBuffer
+	return mb.mustAppendSlice(value)
+}
+
+// reuseOrAppendInt is [KVBuffer.reuseOrAppend]'s integer counterpart.
+func (mb *KVBuffer) reuseOrAppendInt(tok headerSlice, value int64, base int) headerSlice {
+	n := internal.IntLen(value, base)
+	if int(tok.len) >= n {
+		// Reuse: format directly over the existing slot. No free space needed
+		// since n <= tok.len and the slot already lives inside buf.
+		v := strconv.AppendInt(mb.buf[tok.start:tok.start], value, base)
+		tok.len = tokint(len(v))
+		mb.flags |= flagMangledBuffer
+		return tok
+	}
+	return mb.appendInt(value, base, n)
+}
+
+// appendInt reserves space (growing or flagging OOM) and appends value as a new slot.
+func (mb *KVBuffer) appendInt(value int64, base, n int) headerSlice {
+	if !mb.reserve(n) {
+		return headerSlice{} // Drop and flag OOM; never panic.
+	}
+	mb.flags |= flagMangledBuffer
+	return mb.mustAppendInt(value, base)
+}
+
 func (mb *KVBuffer) slice(value []byte) headerSlice {
 	if value == nil {
 		return headerSlice{}

http/httpraw/parse.go

@@ -3,8 +3,6 @@ package httpraw
 import (
 	"bytes"
 	"errors"
-	"slices"
-	"strconv"
 	"unsafe"
 
 	"github.com/soypat/lneto/internal"
@@ -18,8 +16,11 @@ var (
 	errNoBoundary        = errors.New("httpraw: multipart boundary not set")
 	errUnparsed          = errors.New("need to finish parsing")
 	errInvalidName       = errors.New("invalid header name")
-	ErrSmallHeaderBuffer = errors.New("httpraw: Header buffer exhausted, increase size")
-	errOOM               = errors.New("httpraw: Header incomplete due to OOM")
+	// ErrBufferExhausted signals a buffer with no room left for the data being
+	// written and no permission to grow, see [KVBuffer.EnableBufferGrowth].
+	// Enlarging the buffer handed to Reset is the only fix; a server answers it
+	// on a request header with 431, RFC 6585 5.
+	ErrBufferExhausted = errors.New("httpraw: buffer exhausted, increase size")
 	// ErrHeaderTooMany signals a header block carrying more fields than
 	// the buffer it is parsed into has room for, see [Header.Reset]. A server
 	// answers it with 431, RFC 6585 5: no larger buffer is coming, so reading
@@ -245,121 +246,6 @@ func (hb *headerBuf) parseFirstLineResponse(initFlags Flags) (statusCode, status
 
 func (kv argsKV) HasValue() bool { return kv.value.start > 0 }
 
-func (h *Header) reuseOrAppend(tok headerSlice, value string) headerSlice {
-	if tok.len > tokint(len(value)) {
-		copy(h.hbuf.kv.musttoken(tok), value)
-		tok.len = tokint(len(value))
-		return tok
-	}
-	return h.appendSlice(value)
-}
-
-func (h *Header) appendSlice(value string) headerSlice {
-	debuglog("http:appendslice:start")
-	if !h.reserve(len(value)) {
-		return headerSlice{}
-	}
-	h.flags |= flagMangledBuffer
-	return h.hbuf.kv.mustAppendSlice(value)
-}
-
-func (h *Header) appendHeader(key, value string) {
-	// reserve accounts for the byte-0 reservation mustAppendSlice makes on an
-	// empty buffer, and drops (flagging OOM) rather than panicking when growth
-	// is disabled and space runs out.
-	if !h.reserve(len(key) + len(value)) {
-		return
-	}
-	h.flags |= flagMangledBuffer
-	hb := &h.hbuf
-	k := hb.mustAppendSlice(key)
-	v := hb.mustAppendSlice(value)
-	debuglog("http:appendhdr:grow-hdrs")
-	hb.headers = append(hb.headers, argsKV{
-		key:   k,
-		value: v,
-	})
-}
-
-// appendHeaderInt is appendHeader's integer counterpart: it appends key and the
-// formatted integer value as a new header field.
-func (h *Header) appendHeaderInt(key string, value int64, base int) {
-	n := internal.IntLen(value, base)
-	if !h.reserve(len(key) + n) {
-		return // Drop and flag OOM; never panic.
-	}
-	h.flags |= flagMangledBuffer
-	hb := &h.hbuf
-	k := hb.mustAppendSlice(key)
-	v := hb.mustAppendInt(value, base)
-	hb.headers = append(hb.headers, argsKV{
-		key:   k,
-		value: v,
-	})
-}
-
-// reserve ensures need free bytes are available in the buffer, growing it when
-// permitted. It accounts for the byte-0 reservation on an empty buffer (see
-// mustAppendSlice). It returns false and sets flagOOMReached when the space
-// cannot be guaranteed: a tokint offset overflow, or a full buffer with
-// flagNoBufferGrow set.
-func (h *Header) reserve(need int) bool {
-	hb := &h.hbuf
-	if len(hb.buf) == 0 {
-		need++ // mustAppend* reserves byte 0 on an empty buffer.
-	}
-	if len(hb.buf)+need > maxBufLen {
-		h.flags |= flagOOMReached // Offsets would overflow uint16 tokint.
-		return false
-	}
-	if need > hb.free() {
-		if h.flags.HasAny(flagNoBufferGrow) {
-			h.flags |= flagOOMReached
-			return false
-		}
-		hb.buf = slices.Grow(hb.buf, need)
-	}
-	return true
-}
-
-// reuseOrAppendInt writes value into tok's slot in place when it fits, avoiding
-// any buffer growth; otherwise it appends a fresh slot.
-func (h *Header) reuseOrAppendInt(tok headerSlice, value int64, base int) headerSlice {
-	n := internal.IntLen(value, base)
-	if int(tok.len) >= n {
-		// Reuse: format directly over the existing slot. No free space needed
-		// since n <= tok.len and the slot already lives inside buf.
-		v := strconv.AppendInt(h.hbuf.buf[tok.start:tok.start], value, base)
-		tok.len = tokint(len(v))
-		h.flags |= flagMangledBuffer
-		return tok
-	}
-	return h.appendInt(value, base, n)
-}
-
-// appendInt reserves space (growing or flagging OOM) and appends value as a new slot.
-func (h *Header) appendInt(value int64, base, n int) headerSlice {
-	if !h.reserve(n) {
-		return headerSlice{} // Drop and flag OOM; never panic.
-	}
-	h.flags |= flagMangledBuffer
-	return h.hbuf.mustAppendInt(value, base)
-}
-
-// mustAppendInt formats value into the buffer's free region and commits it.
-// The caller must have reserved at least internal.IntLen(value, base) free bytes.
-func (hb *headerBuf) mustAppendInt(value int64, base int) headerSlice {
-	L := len(hb.buf)
-	if L == 0 {
-		L++ // Valid key-values start after byte 0.
-	}
-	v := strconv.AppendInt(hb.buf[L:L], value, base)
-	hb.buf = hb.buf[:L+len(v)]
-	return hb.slice(hb.buf[L : L+len(v)])
-}
-
-func (hb *headerBuf) noKV() argsKV { return argsKV{} }
-
 func (hb *headerBuf) next(ss *scannerState) argsKV {
 	if !ss.initialized {
 		ss.nextColon = -1
@@ -369,10 +255,10 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 	blen := len(buf)
 	if blen >= 2 && buf[0] == '\r' && buf[1] == '\n' {
 		hb.off += 2
-		return hb.noKV() // \r\n\r\n Ends header.
+		return hb.kv.noKV() // \r\n\r\n Ends header.
 	} else if blen >= 1 && buf[0] == '\n' {
 		hb.off += 1
-		return hb.noKV() // \n\n Ends header.
+		return hb.kv.noKV() // \n\n Ends header.
 	}
 
 	// n is parsing offset. Will start by storing colon index.
@@ -388,18 +274,18 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 			// A header name should always at some point be followed by a \n
 			// even if it's the one that terminates the header block.
 			ss.err = ErrNeedMoreData
-			return hb.noKV()
+			return hb.kv.noKV()
 		} else if x < n {
 			// There was a \n before the colon! This is invalid.
 			ss.err = errInvalidName
-			return hb.noKV()
+			return hb.kv.noKV()
 		} else if n < 0 {
 			// A newline is present (x>=0 reached here) but the line has no
 			// colon: malformed, not incomplete. A split arriving before the
 			// colon has no newline yet and is caught by the x<0 branch above,
 			// so it still returns ErrNeedMoreData.
 			ss.err = errInvalidName
-			return hb.noKV()
+			return hb.kv.noKV()
 		}
 	}
 	// n stores colon position by now.
@@ -407,7 +293,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 		// Spaces between the header key and colon are not allowed.
 		// See RFC 7230, Section 3.2.4.
 		ss.err = errInvalidName
-		return hb.noKV()
+		return hb.kv.noKV()
 	}
 
 	// Ready to store key..
@@ -426,7 +312,7 @@ func (hb *headerBuf) next(ss *scannerState) argsKV {
 		if nl < 0 || nl+n+1 == len(buf) {
 			// No newline or newline is last character and can't know if is multiline.
 			ss.err = ErrNeedMoreData
-			return hb.noKV()
+			return hb.kv.noKV()
 		}
 		n += nl + 1 // Index of the newly found newline.
 		nextChar := buf[n]

http/httpraw/parse_test.go

@@ -17,13 +17,10 @@ func TestTryParse_IncrementalRequest(t *testing.T) {
 	var done bool
 	var doneIdx int
 	for i, chunk := range chunks {
-		n, err := hdr.ReadFromBytes([]byte(chunk))
+		err := hdr.ReadFromBytes([]byte(chunk))
 		if err != nil {
 			t.Fatalf("ReadFromBytes: %v", err)
 		}
-		if n != len(chunk) {
-			t.Fatalf("expected %d bytes read, got %d", len(chunk), n)
-		}
 
 		var needMore bool
 		needMore, err = hdr.TryParse(false)
@@ -58,13 +55,10 @@ func TestTryParse_IncrementalRequest(t *testing.T) {
 
 	// Verify headers via ForEach.
 	headers := make(map[string]string)
-	err := hdr.ForEach(func(key, value []byte) error {
+	hdr.ForEach(func(key, value []byte) bool {
 		headers[string(key)] = string(value)
-		return nil
+		return true
 	})
-	if err != nil {
-		t.Fatal(err)
-	}
 	if headers["Host"] != "example.com" {
 		t.Errorf("Host = %q; want example.com", headers["Host"])
 	}
@@ -176,7 +170,7 @@ func TestReadFromBytes_Empty(t *testing.T) {
 	var hdr Header
 	hdr.Reset(make([]byte, 0, 256), numHeaderCapacity)
 
-	_, err := hdr.ReadFromBytes(nil)
+	err := hdr.ReadFromBytes(nil)
 	if err == nil {
 		t.Fatal("expected error for empty bytes")
 	}
@@ -209,7 +203,7 @@ func TestEnableBufferGrowth(t *testing.T) {
 	for i := range big {
 		big[i] = 'A'
 	}
-	_, err := hdr.ReadFromBytes(big)
+	err := hdr.ReadFromBytes(big)
 	if err == nil {
 		t.Fatal("expected error when buffer growth disabled and data exceeds capacity")
 	}
@@ -228,11 +222,11 @@ func TestHeader_Add(t *testing.T) {
 
 	// ForEach should find both.
 	var values []string
-	hdr.ForEach(func(key, value []byte) error {
+	hdr.ForEach(func(key, value []byte) bool {
 		if string(key) == "X-Custom" {
 			values = append(values, string(value))
 		}
-		return nil
+		return true
 	})
 	if len(values) != 2 {
 		t.Fatalf("expected 2 X-Custom headers, got %d", len(values))