Source file src/encoding/json/v2_options.go
1 // Copyright 2023 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 //go:build goexperiment.jsonv2 6 7 // Migrating to v2 8 // 9 // This package (i.e., [encoding/json]) is now formally known as the v1 package 10 // since a v2 package now exists at [encoding/json/v2]. 11 // All the behavior of the v1 package is implemented in terms of 12 // the v2 package with the appropriate set of options specified that 13 // preserve the historical behavior of v1. 14 // 15 // The [jsonv2.Marshal] function is the newer equivalent of v1 [Marshal]. 16 // The [jsonv2.Unmarshal] function is the newer equivalent of v1 [Unmarshal]. 17 // The v2 functions have the same calling signature as the v1 equivalent 18 // except that they take in variadic [Options] arguments that can be specified 19 // to alter the behavior of marshal or unmarshal. Both v1 and v2 generally 20 // behave in similar ways, but there are some notable differences. 21 // 22 // The following is a list of differences between v1 and v2: 23 // 24 // - In v1, JSON object members are unmarshaled into a Go struct using a 25 // case-insensitive name match with the JSON name of the fields. 26 // In contrast, v2 matches fields using an exact, case-sensitive match. 27 // The [jsonv2.MatchCaseInsensitiveNames] and [MatchCaseSensitiveDelimiter] 28 // options control this behavior difference. To explicitly specify a Go struct 29 // field to use a particular name matching scheme, either the `case:ignore` 30 // or the `case:strict` field option can be specified. 31 // Field-specified options take precedence over caller-specified options. 32 // 33 // - In v1, when marshaling a Go struct, a field marked as `omitempty` 34 // is omitted if the field value is an "empty" Go value, which is defined as 35 // false, 0, a nil pointer, a nil interface value, and 36 // any empty array, slice, map, or string. In contrast, v2 redefines 37 // `omitempty` to omit a field if it encodes as an "empty" JSON value, 38 // which is defined as a JSON null, or an empty JSON string, object, or array. 39 // The [OmitEmptyWithLegacySemantics] option controls this behavior difference. 40 // Note that `omitempty` behaves identically in both v1 and v2 for a 41 // Go array, slice, map, or string (assuming no user-defined MarshalJSON method 42 // overrides the default representation). Existing usages of `omitempty` on a 43 // Go bool, number, pointer, or interface value should migrate to specifying 44 // `omitzero` instead (which is identically supported in both v1 and v2). 45 // 46 // - In v1, a Go struct field marked as `string` can be used to quote a 47 // Go string, bool, or number as a JSON string. It does not recursively 48 // take effect on composite Go types. In contrast, v2 restricts 49 // the `string` option to only quote a Go number as a JSON string. 50 // It does recursively take effect on Go numbers within a composite Go type. 51 // The [StringifyWithLegacySemantics] option controls this behavior difference. 52 // 53 // - In v1, a nil Go slice or Go map is marshaled as a JSON null. 54 // In contrast, v2 marshals a nil Go slice or Go map as 55 // an empty JSON array or JSON object, respectively. 56 // The [jsonv2.FormatNilSliceAsNull] and [jsonv2.FormatNilMapAsNull] options 57 // control this behavior difference. To explicitly specify a Go struct field 58 // to use a particular representation for nil, either the `format:emitempty` 59 // or `format:emitnull` field option can be specified. 60 // Field-specified options take precedence over caller-specified options. 61 // 62 // - In v1, a Go array may be unmarshaled from a JSON array of any length. 63 // In contrast, in v2 a Go array must be unmarshaled from a JSON array 64 // of the same length, otherwise it results in an error. 65 // The [UnmarshalArrayFromAnyLength] option controls this behavior difference. 66 // 67 // - In v1, a Go byte array is represented as a JSON array of JSON numbers. 68 // In contrast, in v2 a Go byte array is represented as a Base64-encoded JSON string. 69 // The [FormatByteArrayAsArray] option controls this behavior difference. 70 // To explicitly specify a Go struct field to use a particular representation, 71 // either the `format:array` or `format:base64` field option can be specified. 72 // Field-specified options take precedence over caller-specified options. 73 // 74 // - In v1, MarshalJSON methods declared on a pointer receiver are only called 75 // if the Go value is addressable. In contrast, in v2 a MarshalJSON method 76 // is always callable regardless of addressability. 77 // The [CallMethodsWithLegacySemantics] option controls this behavior difference. 78 // 79 // - In v1, MarshalJSON and UnmarshalJSON methods are never called for Go map keys. 80 // In contrast, in v2 a MarshalJSON or UnmarshalJSON method is eligible for 81 // being called for Go map keys. 82 // The [CallMethodsWithLegacySemantics] option controls this behavior difference. 83 // 84 // - In v1, a Go map is marshaled in a deterministic order. 85 // In contrast, in v2 a Go map is marshaled in a non-deterministic order. 86 // The [jsonv2.Deterministic] option controls this behavior difference. 87 // 88 // - In v1, JSON strings are encoded with HTML-specific or JavaScript-specific 89 // characters being escaped. In contrast, in v2 JSON strings use the minimal 90 // encoding and only escape if required by the JSON grammar. 91 // The [jsontext.EscapeForHTML] and [jsontext.EscapeForJS] options 92 // control this behavior difference. 93 // 94 // - In v1, bytes of invalid UTF-8 within a string are silently replaced with 95 // the Unicode replacement character. In contrast, in v2 the presence of 96 // invalid UTF-8 results in an error. The [jsontext.AllowInvalidUTF8] option 97 // controls this behavior difference. 98 // 99 // - In v1, a JSON object with duplicate names is permitted. 100 // In contrast, in v2 a JSON object with duplicate names results in an error. 101 // The [jsontext.AllowDuplicateNames] option controls this behavior difference. 102 // 103 // - In v1, when unmarshaling a JSON null into a non-empty Go value it will 104 // inconsistently either zero out the value or do nothing. 105 // In contrast, in v2 unmarshaling a JSON null will consistently and always 106 // zero out the underlying Go value. The [MergeWithLegacySemantics] option 107 // controls this behavior difference. 108 // 109 // - In v1, when unmarshaling a JSON value into a non-zero Go value, 110 // it merges into the original Go value for array elements, slice elements, 111 // struct fields (but not map values), 112 // pointer values, and interface values (only if a non-nil pointer). 113 // In contrast, in v2 unmarshal merges into the Go value 114 // for struct fields, map values, pointer values, and interface values. 115 // In general, the v2 semantic merges when unmarshaling a JSON object, 116 // otherwise it replaces the value. The [MergeWithLegacySemantics] option 117 // controls this behavior difference. 118 // 119 // - In v1, a [time.Duration] is represented as a JSON number containing 120 // the decimal number of nanoseconds. In contrast, in v2 a [time.Duration] 121 // has no default representation and results in a runtime error. 122 // The [FormatDurationAsNano] option controls this behavior difference. 123 // To explicitly specify a Go struct field to use a particular representation, 124 // either the `format:nano` or `format:units` field option can be specified. 125 // Field-specified options take precedence over caller-specified options. 126 // 127 // - In v1, errors are never reported at runtime for Go struct types 128 // that have some form of structural error (e.g., a malformed tag option). 129 // In contrast, v2 reports a runtime error for Go types that are invalid 130 // as they relate to JSON serialization. For example, a Go struct 131 // with only unexported fields cannot be serialized. 132 // The [ReportErrorsWithLegacySemantics] option controls this behavior difference. 133 // 134 // As mentioned, the entirety of v1 is implemented in terms of v2, 135 // where options are implicitly specified to opt into legacy behavior. 136 // For example, [Marshal] directly calls [jsonv2.Marshal] with [DefaultOptionsV1]. 137 // Similarly, [Unmarshal] directly calls [jsonv2.Unmarshal] with [DefaultOptionsV1]. 138 // The [DefaultOptionsV1] option represents the set of all options that specify 139 // default v1 behavior. 140 // 141 // For many of the behavior differences, there are Go struct field options 142 // that the author of a Go type can specify to control the behavior such that 143 // the type is represented identically in JSON under either v1 or v2 semantics. 144 // 145 // The availability of [DefaultOptionsV1] and [jsonv2.DefaultOptionsV2], 146 // where later options take precedence over former options allows for 147 // a gradual migration from v1 to v2. For example: 148 // 149 // - jsonv1.Marshal(v) 150 // uses default v1 semantics. 151 // 152 // - jsonv2.Marshal(v, jsonv1.DefaultOptionsV1()) 153 // is semantically equivalent to jsonv1.Marshal 154 // and thus uses default v1 semantics. 155 // 156 // - jsonv2.Marshal(v, jsonv1.DefaultOptionsV1(), jsontext.AllowDuplicateNames(false)) 157 // uses mostly v1 semantics, but opts into one particular v2-specific behavior. 158 // 159 // - jsonv2.Marshal(v, jsonv1.CallMethodsWithLegacySemantics(true)) 160 // uses mostly v2 semantics, but opts into one particular v1-specific behavior. 161 // 162 // - jsonv2.Marshal(v, ..., jsonv2.DefaultOptionsV2()) 163 // is semantically equivalent to jsonv2.Marshal since 164 // jsonv2.DefaultOptionsV2 overrides any options specified earlier 165 // and thus uses default v2 semantics. 166 // 167 // - jsonv2.Marshal(v) 168 // uses default v2 semantics. 169 // 170 // All new usages of "json" in Go should use the v2 package, 171 // but the v1 package will forever remain supported. 172 package json 173 174 // TODO(https://go.dev/issue/71631): Update the "Migrating to v2" documentation 175 // with default v2 behavior for [time.Duration]. 176 177 import ( 178 "encoding" 179 180 "encoding/json/internal/jsonflags" 181 "encoding/json/internal/jsonopts" 182 "encoding/json/jsontext" 183 jsonv2 "encoding/json/v2" 184 ) 185 186 // Reference encoding, jsonv2, and jsontext packages to assist pkgsite 187 // in being able to hotlink references to those packages. 188 var ( 189 _ encoding.TextMarshaler 190 _ encoding.TextUnmarshaler 191 _ jsonv2.Options 192 _ jsontext.Options 193 ) 194 195 // Options are a set of options to configure the v2 "json" package 196 // to operate with v1 semantics for particular features. 197 // Values of this type can be passed to v2 functions like 198 // [jsonv2.Marshal] or [jsonv2.Unmarshal]. 199 // Instead of referencing this type, use [jsonv2.Options]. 200 // 201 // See the "Migrating to v2" section for guidance on how to migrate usage 202 // of "json" from using v1 to using v2 instead. 203 type Options = jsonopts.Options 204 205 // DefaultOptionsV1 is the full set of all options that define v1 semantics. 206 // It is equivalent to the following boolean options being set to true: 207 // 208 // - [CallMethodsWithLegacySemantics] 209 // - [FormatByteArrayAsArray] 210 // - [FormatBytesWithLegacySemantics] 211 // - [FormatDurationAsNano] 212 // - [MatchCaseSensitiveDelimiter] 213 // - [MergeWithLegacySemantics] 214 // - [OmitEmptyWithLegacySemantics] 215 // - [ParseBytesWithLooseRFC4648] 216 // - [ParseTimeWithLooseRFC3339] 217 // - [ReportErrorsWithLegacySemantics] 218 // - [StringifyWithLegacySemantics] 219 // - [UnmarshalArrayFromAnyLength] 220 // - [jsonv2.Deterministic] 221 // - [jsonv2.FormatNilMapAsNull] 222 // - [jsonv2.FormatNilSliceAsNull] 223 // - [jsonv2.MatchCaseInsensitiveNames] 224 // - [jsontext.AllowDuplicateNames] 225 // - [jsontext.AllowInvalidUTF8] 226 // - [jsontext.EscapeForHTML] 227 // - [jsontext.EscapeForJS] 228 // - [jsontext.PreserveRawStrings] 229 // 230 // All other options are not present. 231 // 232 // The [Marshal] and [Unmarshal] functions in this package are 233 // semantically identical to calling the v2 equivalents with this option: 234 // 235 // jsonv2.Marshal(v, jsonv1.DefaultOptionsV1()) 236 // jsonv2.Unmarshal(b, v, jsonv1.DefaultOptionsV1()) 237 func DefaultOptionsV1() Options { 238 return &jsonopts.DefaultOptionsV1 239 } 240 241 // CallMethodsWithLegacySemantics specifies that calling of type-provided 242 // marshal and unmarshal methods follow legacy semantics: 243 // 244 // - When marshaling, a marshal method declared on a pointer receiver 245 // is only called if the Go value is addressable. 246 // Values obtained from an interface or map element are not addressable. 247 // Values obtained from a pointer or slice element are addressable. 248 // Values obtained from an array element or struct field inherit 249 // the addressability of the parent. In contrast, the v2 semantic 250 // is to always call marshal methods regardless of addressability. 251 // 252 // - When marshaling or unmarshaling, the [Marshaler] or [Unmarshaler] 253 // methods are ignored for map keys. However, [encoding.TextMarshaler] 254 // or [encoding.TextUnmarshaler] are still callable. 255 // In contrast, the v2 semantic is to serialize map keys 256 // like any other value (with regard to calling methods), 257 // which may include calling [Marshaler] or [Unmarshaler] methods, 258 // where it is the implementation's responsibility to represent the 259 // Go value as a JSON string (as required for JSON object names). 260 // 261 // - When marshaling, if a map key value implements a marshal method 262 // and is a nil pointer, then it is serialized as an empty JSON string. 263 // In contrast, the v2 semantic is to report an error. 264 // 265 // - When marshaling, if an interface type implements a marshal method 266 // and the interface value is a nil pointer to a concrete type, 267 // then the marshal method is always called. 268 // In contrast, the v2 semantic is to never directly call methods 269 // on interface values and to instead defer evaluation based upon 270 // the underlying concrete value. Similar to non-interface values, 271 // marshal methods are not called on nil pointers and 272 // are instead serialized as a JSON null. 273 // 274 // This affects either marshaling or unmarshaling. 275 // The v1 default is true. 276 func CallMethodsWithLegacySemantics(v bool) Options { 277 if v { 278 return jsonflags.CallMethodsWithLegacySemantics | 1 279 } else { 280 return jsonflags.CallMethodsWithLegacySemantics | 0 281 } 282 } 283 284 // FormatByteArrayAsArray specifies that a Go [N]byte is 285 // formatted as as a normal Go array in contrast to the v2 default of 286 // formatting [N]byte as using binary data encoding (RFC 4648). 287 // If a struct field has a `format` tag option, 288 // then the specified formatting takes precedence. 289 // 290 // This affects either marshaling or unmarshaling. 291 // The v1 default is true. 292 func FormatByteArrayAsArray(v bool) Options { 293 if v { 294 return jsonflags.FormatByteArrayAsArray | 1 295 } else { 296 return jsonflags.FormatByteArrayAsArray | 0 297 } 298 } 299 300 // FormatBytesWithLegacySemantics specifies that handling of 301 // []~byte and [N]~byte types follow legacy semantics: 302 // 303 // - A Go []~byte is to be treated as using some form of 304 // binary data encoding (RFC 4648) in contrast to the v2 default 305 // of only treating []byte as such. In particular, v2 does not 306 // treat slices of named byte types as representing binary data. 307 // 308 // - When marshaling, if a named byte implements a marshal method, 309 // then the slice is serialized as a JSON array of elements, 310 // each of which call the marshal method. 311 // 312 // - When unmarshaling, if the input is a JSON array, 313 // then unmarshal into the []~byte as if it were a normal Go slice. 314 // In contrast, the v2 default is to report an error unmarshaling 315 // a JSON array when expecting some form of binary data encoding. 316 // 317 // This affects either marshaling or unmarshaling. 318 // The v1 default is true. 319 func FormatBytesWithLegacySemantics(v bool) Options { 320 if v { 321 return jsonflags.FormatBytesWithLegacySemantics | 1 322 } else { 323 return jsonflags.FormatBytesWithLegacySemantics | 0 324 } 325 } 326 327 // FormatDurationAsNano specifies that a [time.Duration] is 328 // formatted as a JSON number representing the number of nanoseconds 329 // in contrast to the v2 default of reporting an error. 330 // If a duration field has a `format` tag option, 331 // then the specified formatting takes precedence. 332 // 333 // This affects either marshaling or unmarshaling. 334 // The v1 default is true. 335 func FormatDurationAsNano(v bool) Options { 336 // TODO(https://go.dev/issue/71631): Update documentation with v2 behavior. 337 if v { 338 return jsonflags.FormatDurationAsNano | 1 339 } else { 340 return jsonflags.FormatDurationAsNano | 0 341 } 342 } 343 344 // MatchCaseSensitiveDelimiter specifies that underscores and dashes are 345 // not to be ignored when performing case-insensitive name matching which 346 // occurs under [jsonv2.MatchCaseInsensitiveNames] or the `case:ignore` tag option. 347 // Thus, case-insensitive name matching is identical to [strings.EqualFold]. 348 // Use of this option diminishes the ability of case-insensitive matching 349 // to be able to match common case variants (e.g, "foo_bar" with "fooBar"). 350 // 351 // This affects either marshaling or unmarshaling. 352 // The v1 default is true. 353 func MatchCaseSensitiveDelimiter(v bool) Options { 354 if v { 355 return jsonflags.MatchCaseSensitiveDelimiter | 1 356 } else { 357 return jsonflags.MatchCaseSensitiveDelimiter | 0 358 } 359 } 360 361 // MergeWithLegacySemantics specifies that unmarshaling into a non-zero 362 // Go value follows legacy semantics: 363 // 364 // - When unmarshaling a JSON null, this preserves the original Go value 365 // if the kind is a bool, int, uint, float, string, array, or struct. 366 // Otherwise, it zeros the Go value. 367 // In contrast, the default v2 behavior is to consistently and always 368 // zero the Go value when unmarshaling a JSON null into it. 369 // 370 // - When unmarshaling a JSON value other than null, this merges into 371 // the original Go value for array elements, slice elements, 372 // struct fields (but not map values), 373 // pointer values, and interface values (only if a non-nil pointer). 374 // In contrast, the default v2 behavior is to merge into the Go value 375 // for struct fields, map values, pointer values, and interface values. 376 // In general, the v2 semantic merges when unmarshaling a JSON object, 377 // otherwise it replaces the original value. 378 // 379 // This only affects unmarshaling and is ignored when marshaling. 380 // The v1 default is true. 381 func MergeWithLegacySemantics(v bool) Options { 382 if v { 383 return jsonflags.MergeWithLegacySemantics | 1 384 } else { 385 return jsonflags.MergeWithLegacySemantics | 0 386 } 387 } 388 389 // OmitEmptyWithLegacySemantics specifies that the `omitempty` tag option 390 // follows a definition of empty where a field is omitted if the Go value is 391 // false, 0, a nil pointer, a nil interface value, 392 // or any empty array, slice, map, or string. 393 // This overrides the v2 semantic where a field is empty if the value 394 // marshals as a JSON null or an empty JSON string, object, or array. 395 // 396 // The v1 and v2 definitions of `omitempty` are practically the same for 397 // Go strings, slices, arrays, and maps. Usages of `omitempty` on 398 // Go bools, ints, uints floats, pointers, and interfaces should migrate to use 399 // the `omitzero` tag option, which omits a field if it is the zero Go value. 400 // 401 // This only affects marshaling and is ignored when unmarshaling. 402 // The v1 default is true. 403 func OmitEmptyWithLegacySemantics(v bool) Options { 404 if v { 405 return jsonflags.OmitEmptyWithLegacySemantics | 1 406 } else { 407 return jsonflags.OmitEmptyWithLegacySemantics | 0 408 } 409 } 410 411 // ParseBytesWithLooseRFC4648 specifies that when parsing 412 // binary data encoded as "base32" or "base64", 413 // to ignore the presence of '\r' and '\n' characters. 414 // In contrast, the v2 default is to report an error in order to be 415 // strictly compliant with RFC 4648, section 3.3, 416 // which specifies that non-alphabet characters must be rejected. 417 // 418 // This only affects unmarshaling and is ignored when marshaling. 419 // The v1 default is true. 420 func ParseBytesWithLooseRFC4648(v bool) Options { 421 if v { 422 return jsonflags.ParseBytesWithLooseRFC4648 | 1 423 } else { 424 return jsonflags.ParseBytesWithLooseRFC4648 | 0 425 } 426 } 427 428 // ParseTimeWithLooseRFC3339 specifies that a [time.Time] 429 // parses according to loose adherence to RFC 3339. 430 // In particular, it permits historically incorrect representations, 431 // allowing for deviations in hour format, sub-second separator, 432 // and timezone representation. In contrast, the default v2 behavior 433 // is to strictly comply with the grammar specified in RFC 3339. 434 // 435 // This only affects unmarshaling and is ignored when marshaling. 436 // The v1 default is true. 437 func ParseTimeWithLooseRFC3339(v bool) Options { 438 if v { 439 return jsonflags.ParseTimeWithLooseRFC3339 | 1 440 } else { 441 return jsonflags.ParseTimeWithLooseRFC3339 | 0 442 } 443 } 444 445 // ReportErrorsWithLegacySemantics specifies that Marshal and Unmarshal 446 // should report errors with legacy semantics: 447 // 448 // - When marshaling or unmarshaling, the returned error values are 449 // usually of types such as [SyntaxError], [MarshalerError], 450 // [UnsupportedTypeError], [UnsupportedValueError], 451 // [InvalidUnmarshalError], or [UnmarshalTypeError]. 452 // In contrast, the v2 semantic is to always return errors as either 453 // [jsonv2.SemanticError] or [jsontext.SyntacticError]. 454 // 455 // - When marshaling, if a user-defined marshal method reports an error, 456 // it is always wrapped in a [MarshalerError], even if the error itself 457 // is already a [MarshalerError], which may lead to multiple redundant 458 // layers of wrapping. In contrast, the v2 semantic is to 459 // always wrap an error within [jsonv2.SemanticError] 460 // unless it is already a semantic error. 461 // 462 // - When unmarshaling, if a user-defined unmarshal method reports an error, 463 // it is never wrapped and reported verbatim. In contrast, the v2 semantic 464 // is to always wrap an error within [jsonv2.SemanticError] 465 // unless it is already a semantic error. 466 // 467 // - When marshaling or unmarshaling, if a Go struct contains type errors 468 // (e.g., conflicting names or malformed field tags), then such errors 469 // are ignored and the Go struct uses a best-effort representation. 470 // In contrast, the v2 semantic is to report a runtime error. 471 // 472 // - When unmarshaling, the syntactic structure of the JSON input 473 // is fully validated before performing the semantic unmarshaling 474 // of the JSON data into the Go value. Practically speaking, 475 // this means that JSON input with syntactic errors do not result 476 // in any mutations of the target Go value. In contrast, the v2 semantic 477 // is to perform a streaming decode and gradually unmarshal the JSON input 478 // into the target Go value, which means that the Go value may be 479 // partially mutated when a syntactic error is encountered. 480 // 481 // - When unmarshaling, a semantic error does not immediately terminate the 482 // unmarshal procedure, but rather evaluation continues. 483 // When unmarshal returns, only the first semantic error is reported. 484 // In contrast, the v2 semantic is to terminate unmarshal the moment 485 // an error is encountered. 486 // 487 // This affects either marshaling or unmarshaling. 488 // The v1 default is true. 489 func ReportErrorsWithLegacySemantics(v bool) Options { 490 if v { 491 return jsonflags.ReportErrorsWithLegacySemantics | 1 492 } else { 493 return jsonflags.ReportErrorsWithLegacySemantics | 0 494 } 495 } 496 497 // StringifyWithLegacySemantics specifies that the `string` tag option 498 // may stringify bools and string values. It only takes effect on fields 499 // where the top-level type is a bool, string, numeric kind, or a pointer to 500 // such a kind. Specifically, `string` will not stringify bool, string, 501 // or numeric kinds within a composite data type 502 // (e.g., array, slice, struct, map, or interface). 503 // 504 // When marshaling, such Go values are serialized as their usual 505 // JSON representation, but quoted within a JSON string. 506 // When unmarshaling, such Go values must be deserialized from 507 // a JSON string containing their usual JSON representation or 508 // Go number representation for that numeric kind. 509 // Note that the Go number grammar is a superset of the JSON number grammar. 510 // A JSON null quoted in a JSON string is a valid substitute for JSON null 511 // while unmarshaling into a Go value that `string` takes effect on. 512 // 513 // This affects either marshaling or unmarshaling. 514 // The v1 default is true. 515 func StringifyWithLegacySemantics(v bool) Options { 516 if v { 517 return jsonflags.StringifyWithLegacySemantics | 1 518 } else { 519 return jsonflags.StringifyWithLegacySemantics | 0 520 } 521 } 522 523 // UnmarshalArrayFromAnyLength specifies that Go arrays can be unmarshaled 524 // from input JSON arrays of any length. If the JSON array is too short, 525 // then the remaining Go array elements are zeroed. If the JSON array 526 // is too long, then the excess JSON array elements are skipped over. 527 // 528 // This only affects unmarshaling and is ignored when marshaling. 529 // The v1 default is true. 530 func UnmarshalArrayFromAnyLength(v bool) Options { 531 if v { 532 return jsonflags.UnmarshalArrayFromAnyLength | 1 533 } else { 534 return jsonflags.UnmarshalArrayFromAnyLength | 0 535 } 536 } 537 538 // unmarshalAnyWithRawNumber specifies that unmarshaling a JSON number into 539 // an empty Go interface should use the Number type instead of a float64. 540 func unmarshalAnyWithRawNumber(v bool) Options { 541 if v { 542 return jsonflags.UnmarshalAnyWithRawNumber | 1 543 } else { 544 return jsonflags.UnmarshalAnyWithRawNumber | 0 545 } 546 } 547