Files
ollama/model/models/gemma4/tokenizer_reference_test.go
Daniel Hiltgen de9673ac3f tokenizer: add byte fallback for SentencePiece BPE encoding (#15232)
* tokenizer: add byte fallback for SentencePiece BPE encoding

When BPE merging produces tokens not in the vocabulary, fall back to
encoding each UTF-8 byte as <0xHH> byte tokens instead of silently
dropping the character. Also teach Decode to convert <0xHH> tokens
back to raw bytes.

Fixes #15229, fixes #15231

* tokenizer fixes
2026-04-02 13:04:45 -07:00

342 lines
10 KiB
Go

package gemma4
// TestGemma4TokenizerMatchesReference verifies our BPE tokenizer matches
// the Rust tokenizers library (the reference implementation) for Gemma 4.
//
// The test loads vocabulary from any local ollama gemma4 GGUF model.
// Skips if no gemma4 model is installed.
//
// Set VERIFY_HF_TOKENIZER=1 to verify against the Rust tokenizers library
// via Python. Requires python3 with tokenizers>=0.21 on PATH:
//
// VERIFY_HF_TOKENIZER=1 go test ./model/models/gemma4/ -run TestGemma4Tokenizer -v
//
// Workflow for adding a new test case:
// 1. Add {name: "...", input: "..."} to the test list (no want field)
// 2. Run with VERIFY_HF_TOKENIZER=1 — it prints the reference IDs
// 3. Paste those IDs into the want field
// 4. Run without VERIFY_HF_TOKENIZER — our tokenizer must match
import (
"encoding/json"
"fmt"
"os"
"os/exec"
"path/filepath"
"strings"
"testing"
"github.com/ollama/ollama/envconfig"
"github.com/ollama/ollama/fs/gguf"
"github.com/ollama/ollama/tokenizer"
)
type tokenizerRefCase struct {
name string
input string
want []int32
}
// Reference token IDs generated by the Rust tokenizers library using
// vocab/merges from a gemma4 GGUF with add_special_tokens=False.
var gemma4TokenizerRefCases = []tokenizerRefCase{
// Basic ASCII
{name: "basic word", input: "hello", want: []int32{23391}},
{name: "two words", input: "hello world", want: []int32{23391, 1902}},
{name: "punctuation", input: "Hello, World!", want: []int32{9259, 236764, 4109, 236888}},
// Space handling (pretokenizer bug: GPT-2 splitter mangled leading/multiple spaces)
{name: "leading space", input: " hello", want: []int32{29104}},
{name: "double leading space", input: " hello", want: []int32{138, 23391}},
{name: "double space between words", input: "hello world", want: []int32{23391, 138, 12392}},
{name: "only spaces", input: " ", want: []int32{139}},
{name: "repeated spaces", input: " ", want: []int32{142}},
{name: "leading spaces phrase", input: " leading spaces", want: []int32{5830, 9952}},
{name: "multiple interior spaces", input: "multiple spaces", want: []int32{43819, 140, 35220}},
// Polish diacritics (issue #15231 — Decode mangled U+0105-U+0142)
{name: "polish diacritics", input: "ąęśćżźółń", want: []int32{237198, 237202, 14732, 237277, 238992, 24875, 238041}},
{name: "polish sentence", input: "Zażółć gęślą jaźń", want: []int32{236953, 40512, 24875, 237289, 549, 237202, 62081, 237198, 4828, 238992, 238041}},
// French accents (issue #15229 — Decode mangled U+00E0-U+00FF)
{name: "french accents", input: "café résumé naïve", want: []int32{123125, 236859, 118515, 120362}},
{name: "french with apostrophe", input: "L'élève a mangé", want: []int32{236798, 236789, 161654, 496, 14695, 236859}},
// German umlauts
{name: "german umlauts", input: "über Straße Größe", want: []int32{28223, 80176, 112880}},
// Codepoints in GPT-2 byte reversal range (U+0100-U+0142)
{name: "codepoints in gpt2 byte range", input: "ąęćł", want: []int32{237198, 226110, 237114}},
{name: "latin extended A", input: "ĀāĂ㥹", want: []int32{241920, 237448, 241645, 237106, 243514, 237198}},
// CJK & Japanese
{name: "chinese", input: "你好世界", want: []int32{144626, 12811}},
{name: "japanese hiragana", input: "こんにちは", want: []int32{85141}},
// Mixed scripts
{name: "mixed scripts", input: "hello ąęść world café 你好", want: []int32{23391, 236743, 237198, 237202, 14732, 1902, 33443, 43758, 237389}},
// Whitespace
{name: "empty string", input: "", want: []int32{}},
{name: "newlines", input: "\n\n", want: []int32{108}},
{name: "tabs", input: "\t\t", want: []int32{255969}},
// Code-like content
{name: "python code", input: "def foo(x): return x + 1", want: []int32{2063, 46293, 236769, 236781, 1473, 994, 1123, 900, 236743, 236770}},
{name: "json", input: `{"key": "value"}`, want: []int32{14937, 2478, 1083, 623, 2394, 25938}},
// Misc
{name: "repeated char", input: "aaaaaa", want: []int32{50354, 9236}},
{name: "emoji", input: "hello 👋 world", want: []int32{23391, 155818, 1902}},
{name: "digits", input: "12345", want: []int32{236770, 236778, 236800, 236812, 236810}},
{name: "float", input: "3.14159", want: []int32{236800, 236761, 236770, 236812, 236770, 236810, 236819}},
}
// findGemma4GGUF looks for any gemma4 model GGUF in the local ollama store.
func findGemma4GGUF() (string, error) {
modelsDir := envconfig.Models()
manifestDir := filepath.Join(modelsDir, "manifests", "registry.ollama.ai", "library", "gemma4")
entries, err := os.ReadDir(manifestDir)
if err != nil {
return "", fmt.Errorf("no gemma4 manifests in %s: %w", manifestDir, err)
}
blobDir := filepath.Join(modelsDir, "blobs")
for _, entry := range entries {
if entry.IsDir() {
continue
}
data, err := os.ReadFile(filepath.Join(manifestDir, entry.Name()))
if err != nil {
continue
}
var manifest struct {
Layers []struct {
MediaType string `json:"mediaType"`
Digest string `json:"digest"`
} `json:"layers"`
}
if err := json.Unmarshal(data, &manifest); err != nil {
continue
}
for _, layer := range manifest.Layers {
if layer.MediaType == "application/vnd.ollama.image.model" {
blobPath := filepath.Join(blobDir, strings.Replace(layer.Digest, ":", "-", 1))
if _, err := os.Stat(blobPath); err == nil {
return blobPath, nil
}
}
}
}
return "", fmt.Errorf("no gemma4 model blob found in %s", modelsDir)
}
// loadGemma4Tokenizer opens a GGUF and builds a BPE tokenizer from its
// tokenizer metadata — the same configuration used at inference time.
func loadGemma4Tokenizer(t *testing.T, ggufPath string) tokenizer.BytePairEncoding {
t.Helper()
f, err := gguf.Open(ggufPath)
if err != nil {
t.Fatalf("gguf.Open: %v", err)
}
defer f.Close()
tokens := f.KeyValue("tokenizer.ggml.tokens").Strings()
if len(tokens) == 0 {
t.Fatal("no tokenizer.ggml.tokens in GGUF")
}
scores64 := f.KeyValue("tokenizer.ggml.scores").Floats()
scores := make([]float32, len(scores64))
for i, s := range scores64 {
scores[i] = float32(s)
}
types64 := f.KeyValue("tokenizer.ggml.token_type").Ints()
types := make([]int32, len(types64))
for i, tt := range types64 {
types[i] = int32(tt)
}
merges := f.KeyValue("tokenizer.ggml.merges").Strings()
vocab := &tokenizer.Vocabulary{
Values: tokens,
Types: types,
Scores: scores,
Merges: merges,
BOS: []int32{2},
EOS: []int32{1},
AddBOS: false,
}
return tokenizer.NewBytePairEncodingWithOptions(vocab, []string{},
tokenizer.WithSentencePieceNormalizer())
}
// writeTokenizerJSON reconstructs a tokenizer.json from GGUF metadata
// for the Rust tokenizers library to load as an independent reference.
func writeTokenizerJSON(t *testing.T, ggufPath string) string {
t.Helper()
f, err := gguf.Open(ggufPath)
if err != nil {
t.Fatalf("gguf.Open: %v", err)
}
defer f.Close()
tokens := f.KeyValue("tokenizer.ggml.tokens").Strings()
mergeStrs := f.KeyValue("tokenizer.ggml.merges").Strings()
vocab := make(map[string]int, len(tokens))
for i, tok := range tokens {
vocab[tok] = i
}
merges := make([][2]string, len(mergeStrs))
for i, m := range mergeStrs {
parts := strings.SplitN(m, " ", 2)
if len(parts) == 2 {
merges[i] = [2]string{parts[0], parts[1]}
}
}
tj := map[string]any{
"version": "1.0",
"model": map[string]any{
"type": "BPE",
"vocab": vocab,
"merges": merges,
},
"normalizer": map[string]any{
"type": "Replace",
"pattern": map[string]string{"String": " "},
"content": "\u2581",
},
}
tmpFile, err := os.CreateTemp(t.TempDir(), "gemma4_tokenizer_*.json")
if err != nil {
t.Fatalf("create temp file: %v", err)
}
if err := json.NewEncoder(tmpFile).Encode(tj); err != nil {
tmpFile.Close()
t.Fatalf("encode tokenizer.json: %v", err)
}
tmpFile.Close()
return tmpFile.Name()
}
func TestGemma4TokenizerMatchesReference(t *testing.T) {
ggufPath, err := findGemma4GGUF()
if err != nil {
t.Skipf("skipping: %v", err)
}
t.Logf("using GGUF: %s", ggufPath)
tok := loadGemma4Tokenizer(t, ggufPath)
verify := os.Getenv("VERIFY_HF_TOKENIZER") != ""
var tokenizerJSONPath string
if verify {
if err := exec.Command("python3", "-c", "from tokenizers import Tokenizer").Run(); err != nil {
t.Fatal("VERIFY_HF_TOKENIZER=1 requires python3 with tokenizers>=0.21 on PATH")
}
tokenizerJSONPath = writeTokenizerJSON(t, ggufPath)
defer os.Remove(tokenizerJSONPath)
t.Log("VERIFY_HF_TOKENIZER=1: verifying against Rust tokenizers library")
}
for _, tc := range gemma4TokenizerRefCases {
t.Run(tc.name, func(t *testing.T) {
ids, err := tok.Encode(tc.input, false)
if err != nil {
t.Fatalf("Encode(%q): %v", tc.input, err)
}
if tc.want != nil {
if fmt.Sprint(ids) != fmt.Sprint(tc.want) {
t.Errorf("Encode(%q):\n got: %v\n want: %v", tc.input, ids, tc.want)
}
} else {
t.Errorf("no expected IDs for %q; our tokenizer produced: %v", tc.input, ids)
}
if len(ids) > 0 {
decoded, err := tok.Decode(ids)
if err != nil {
t.Fatalf("Decode: %v", err)
}
if decoded != tc.input {
t.Errorf("roundtrip %q: Decode(Encode) = %q", tc.input, decoded)
}
}
if verify {
refIDs := encodeWithRustTokenizer(t, tokenizerJSONPath, tc.input)
if fmt.Sprint(refIDs) != fmt.Sprint(ids) {
fmt.Fprintf(os.Stderr, "\nREFERENCE OUTPUT for %s (copy-paste as want):\nwant: []int32{%s},\n\n",
tc.name, int32SliceStr(refIDs))
}
if tc.want != nil && fmt.Sprint(refIDs) != fmt.Sprint(tc.want) {
t.Errorf("hardcoded expected IDs don't match reference for %q:\n ref: %v\n hardcoded: %v",
tc.input, refIDs, tc.want)
}
}
})
}
}
func encodeWithRustTokenizer(t *testing.T, tokenizerPath, text string) []int32 {
t.Helper()
if text == "" {
return nil
}
script := fmt.Sprintf(`
from tokenizers import Tokenizer
t = Tokenizer.from_file(%q)
ids = t.encode(%q, add_special_tokens=False).ids
print(",".join(str(i) for i in ids))
`, tokenizerPath, text)
cmd := exec.Command("python3", "-c", script)
var stdout, stderr strings.Builder
cmd.Stdout = &stdout
cmd.Stderr = &stderr
if err := cmd.Run(); err != nil {
t.Fatalf("python3 failed: %v\nstderr: %s", err, stderr.String())
}
parts := strings.Split(strings.TrimSpace(stdout.String()), ",")
var ids []int32
for _, p := range parts {
if p == "" {
continue
}
var id int32
fmt.Sscanf(p, "%d", &id)
ids = append(ids, id)
}
return ids
}
func int32SliceStr(ids []int32) string {
parts := make([]string, len(ids))
for i, id := range ids {
parts[i] = fmt.Sprintf("%d", id)
}
return strings.Join(parts, ", ")
}