made AddedSnapshotID optional for V1

internal/avro_schemas.go

@@ -40,7 +40,7 @@ func init() {
 			{"name": "partition_spec_id", "type": "int", "doc": "Spec ID used to write", "field-id": 502},
 			{
 				"name": "added_snapshot_id",
-				"type": "long",
+				"type": ["null", "long"],
 				"doc": "Snapshot ID that added the manifest",
 				"field-id": 503
 			},

manifest.go

@@ -52,17 +52,21 @@ type ManifestV1Builder struct {
 // NewManifestV1Builder is passed all of the required fields and then allows
 // all of the optional fields to be set by calling the corresponding methods
 // before calling [ManifestV1Builder.Build] to construct the object.
-func NewManifestV1Builder(path string, length int64, partitionSpecID int32, addedSnapshotID int64) *ManifestV1Builder {
+func NewManifestV1Builder(path string, length int64, partitionSpecID int32) *ManifestV1Builder {
 	return &ManifestV1Builder{
 		m: &manifestFileV1{
-			Path:            path,
-			Len:             length,
-			SpecID:          partitionSpecID,
-			AddedSnapshotID: addedSnapshotID,
+			Path:   path,
+			Len:    length,
+			SpecID: partitionSpecID,
 		},
 	}
 }
 
+func (b *ManifestV1Builder) AddedSnapshotID(id int64) *ManifestV1Builder {
+	b.m.AddedSnapshotID = &id
+	return b
+}
+
 func (b *ManifestV1Builder) AddedFiles(cnt int32) *ManifestV1Builder {
 	b.m.AddedFilesCount = &cnt
 	return b
@@ -115,7 +119,7 @@ type manifestFileV1 struct {
 	Path               string          `avro:"manifest_path"`
 	Len                int64           `avro:"manifest_length"`
 	SpecID             int32           `avro:"partition_spec_id"`
-	AddedSnapshotID    int64           `avro:"added_snapshot_id"`
+	AddedSnapshotID    *int64          `avro:"added_snapshot_id"`
 	AddedFilesCount    *int32          `avro:"added_data_files_count"`
 	ExistingFilesCount *int32          `avro:"existing_data_files_count"`
 	DeletedFilesCount  *int32          `avro:"deleted_data_files_count"`
@@ -134,7 +138,10 @@ func (m *manifestFileV1) ManifestContent() ManifestContent {
 	return ManifestContentData
 }
 func (m *manifestFileV1) SnapshotID() int64 {
-	return m.AddedSnapshotID
+	if m.AddedSnapshotID == nil {
+		return 0
+	}
+	return *m.AddedSnapshotID
 }
 
 func (m *manifestFileV1) AddedDataFiles() int32 {

manifest_test.go

@@ -33,7 +33,8 @@ var (
 	addedRows             int64 = 237993
 	manifestFileRecordsV1       = []ManifestFile{
 		NewManifestV1Builder("/home/iceberg/warehouse/nyc/taxis_partitioned/metadata/0125c686-8aa6-4502-bdcc-b6d17ca41a3b-m0.avro",
-			7989, 0, snapshotID).
+			7989, 0).
+			AddedSnapshotID(snapshotID).
 			AddedFiles(3).
 			ExistingFiles(0).
 			DeletedFiles(0).
@@ -70,6 +71,11 @@ var (
 			EntryStatus: EntryStatusADDED,
 			Snapshot:    entrySnapshotID,
 			Data: dataFile{
+				// bad value for Content but this field doesn't exist in V1
+				// so it shouldn't get written and shouldn't be read back out
+				// so the roundtrip test asserts that we get the default value
+				// back out.
+				Content:          EntryContentEqDeletes,
 				Path:             "/home/iceberg/warehouse/nyc/taxis_partitioned/data/VendorID=null/00000-633-d8a4223e-dc97-45a1-86e1-adaba6e8abd7-00001.parquet",
 				Format:           ParquetFile,
 				PartitionData:    map[string]any{"VendorID": int(1), "tpep_pickup_datetime": time.Unix(1925, 0)},