model: handle multiple eos tokens (#10577)

* get eos_token_id from generation_config.json

* refactor

* include both ids and strings in trace

* comments

* remove special case for gemma3 special vocab (#10743)

model/sentencepiece_test.go

@@ -0,0 +1,172 @@
+package model
+
+import (
+	"log/slog"
+	"os"
+	"path/filepath"
+	"slices"
+	"testing"
+
+	"google.golang.org/protobuf/proto"
+
+	"github.com/ollama/ollama/convert/sentencepiece"
+)
+
+func loadSentencePieceVocab(t *testing.T) SentencePieceModel {
+	t.Helper()
+
+	bts, err := os.ReadFile(filepath.Join("testdata", "gemma2", "tokenizer.model"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var spm sentencepiece.ModelProto
+	if err := proto.Unmarshal(bts, &spm); err != nil {
+		t.Fatal(err)
+	}
+
+	var v Vocabulary
+
+	for _, piece := range spm.GetPieces() {
+		v.Values = append(v.Values, piece.GetPiece())
+		v.Scores = append(v.Scores, piece.GetScore())
+		switch t := piece.GetType(); t {
+		case sentencepiece.ModelProto_SentencePiece_UNKNOWN,
+			sentencepiece.ModelProto_SentencePiece_CONTROL,
+			sentencepiece.ModelProto_SentencePiece_UNUSED,
+			sentencepiece.ModelProto_SentencePiece_BYTE:
+			v.Types = append(v.Types, int32(t))
+		default:
+			tt := int32(sentencepiece.ModelProto_SentencePiece_NORMAL)
+			// todo parse the special tokens file
+			//   - this will roundtrip correctly but the <start_of_turn> and
+			//     <end_of_turn> tokens aren't processed
+			v.Types = append(v.Types, tt)
+		}
+	}
+
+	return NewSentencePieceModel(&v)
+}
+
+func TestSentencePieceEncode(t *testing.T) {
+	logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{Level: slog.LevelDebug}))
+	slog.SetDefault(logger)
+
+	tokenizer := loadSentencePieceVocab(t)
+
+	t.Run("basic roundtrip", func(t *testing.T) {
+		t.Parallel()
+
+		cases := []string{
+			"hello",
+			"hello ",
+			"hello  ",
+			" hello",
+			" hello ",
+			" hello  ",
+			"hello world",
+			"请考试我的软件！12345",
+			"你好",
+			"Hello 你好 world!",
+			"Special characters: !@#$%^&*()_+-=[]{}|;':\",./<>?",
+			"Multilingual: 你好 こんにちは Привет Hola مرحبا",
+			"Numbers and symbols: 123456789 +- */",
+			"Special tokens: <bos> text <eos>",
+			"Code snippets: func main() { fmt.Println(\"Hello World\") }",
+			"Long text: " + "Lorem ipsum dolor sit amet, consectetur adipiscing elit. " +
+				"Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. " +
+				"Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.",
+		}
+
+		for _, want := range cases {
+			ids, err := tokenizer.Encode(want, true)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if got, err := tokenizer.Decode(ids); err != nil {
+				t.Fatal(err)
+			} else if got != want {
+				t.Errorf("got %q, want %q [%#v]", got, want, ids)
+			}
+		}
+	})
+
+	t.Run("special tokens", func(t *testing.T) {
+		type candidate struct {
+			token string
+			ids   []int32
+		}
+
+		cases := []candidate{
+			{"<bos>", []int32{2}},
+			{"<eos>", []int32{1}},
+		}
+
+		for _, want := range cases {
+			ids, err := tokenizer.Encode(want.token, true)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if !slices.Equal(ids, want.ids) {
+				t.Errorf("got %#v, want %#v", ids, want.ids)
+			}
+		}
+	})
+}
+
+func TestSentencePieceModelDecodeByteTokens(t *testing.T) {
+	vocab := &Vocabulary{
+		Values: []string{
+			"normal",
+			"<0xEA>",
+			"<0x41>",
+			"<0xC3>",
+			"<0xA3>",
+		},
+		Types: []int32{
+			TOKEN_TYPE_NORMAL,
+			TOKEN_TYPE_BYTE,
+			TOKEN_TYPE_BYTE,
+			TOKEN_TYPE_BYTE,
+			TOKEN_TYPE_BYTE,
+		},
+		Scores: []float32{0, 0, 0, 0, 0},
+	}
+
+	spm := NewSentencePieceModel(vocab)
+
+	tests := []struct {
+		name     string
+		ids      []int32
+		expected string
+	}{
+		{
+			name:     "single byte token",
+			ids:      []int32{1},
+			expected: "\xea",
+		},
+		{
+			name:     "ASCII byte token",
+			ids:      []int32{2},
+			expected: "A",
+		},
+		{
+			name:     "multiple byte tokens forming UTF-8 character",
+			ids:      []int32{3, 4},
+			expected: "ã",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := spm.Decode(tt.ids)
+			if err != nil {
+				t.Errorf("failed to decode token IDs %v: %v", tt.ids, err)
+			}
+			if result != tt.expected {
+				t.Errorf("got %q, want %q", result, tt.expected)
+			}
+		})
+	}
+}