Lead the changelog with the read-side break, and show each repeatable TLV's shape

CHANGELOG.md

@@ -38,9 +38,15 @@
 - `server()` refuses a `maxOctets` below 1 or not a whole number, `Infinity` included, like its
   other limits. `server({ maxOctets: 0 })` used to start and then refuse every multipart message.
 - `callback_num`, `callback_num_atag`, `callback_num_pres_ind`, `broadcast_area_identifier` and
-  `broadcast_error_status`, the TLVs SMPP allows more than once in a PDU, read as an array of every
+  `broadcast_error_status`, the TLVs SMPP allows more than once in a PDU, keep every occurrence in
-  occurrence in wire order, even where only one arrived, and `objToPdu()` takes an array for them and
+  wire order. A PDU carrying two of one used to keep only the last.
-  refuses a lone value. A PDU carrying two of one used to keep only the last.
+
+  **Reading one of these now needs an index.** `pduObj.tlvs.callback_num?.tagValue` is a `Buffer[]`
+  even where one arrived (a `number[]` for `callback_num_pres_ind` and `broadcast_error_status`), so a
+  `Buffer.isBuffer()` or `typeof` check written for 0.5.0 now reads it as absent. Read `tagValue[0]`
+  for the first occurrence. `objToPdu()`, `session.send()` and `session.sendReturn()` take
+  `{ tagValue: [value] }` for them and refuse a lone value before anything goes out.
+- `cmds.broadcast_sm_resp.tlvMap` is removed; nothing read it.
 
 ## 0.5.0
 

README.md

@@ -610,7 +610,8 @@ if (isCommand(pduObj, 'submit_sm')) {
   carried them, `'udh'` or `'sar'`, or `undefined` for a whole message.
 - `callback_num`, `callback_num_atag`, `callback_num_pres_ind`, `broadcast_area_identifier` and
   `broadcast_error_status` may repeat in one PDU, so each reads as an array of every occurrence in wire
-  order, and `objToPdu()` writes one TLV per element of the array it takes for them.
+  order: `number[]` for `callback_num_pres_ind` and `broadcast_error_status`, `Buffer[]` for the rest.
+  A `broadcast_sm_resp`'s `failed_broadcast_area_identifier` reads as `broadcast_area_identifier`.
 - `messageClassOf(dataCoding)`: `0` for the flash class, `1`, `2` and `3` for the ME-, SIM- and
   TE-specific ones, `undefined` where that `data_coding`'s coding group carries no class.
 
@@ -621,6 +622,8 @@ if (isCommand(pduObj, 'submit_sm')) {
   naming the character, its code point and where it is.
 - Every text field is latin1: addresses, `system_id`, `message_id`, `service_type` and the C-Octet
   String TLVs. A character past `U+00FF` is refused, as is a `U+0000` in a C-Octet String.
+- The five repeatable TLVs take an array, written as one TLV per element; a lone value or an empty
+  array is refused.
 - A `Buffer` goes out exactly as given under any `data_coding`: binary payloads, hand-built user
   data headers, deliberately malformed bodies.
 - `session.send()` and `session.sendReturn()` build through the same codec and refuse the same bodies.

src/defs/tlvs.ts

@@ -154,7 +154,7 @@ function occurrences(value: TlvValue, multiple: boolean): Result<{ values: Param
 		return Array.isArray(value) ? { err: new Error('takes one value, not an array') } : { values: [value] };
 	}
 
-	if (!Array.isArray(value)) return { err: new Error('is repeatable, give an array of its values') };
+	if (!Array.isArray(value)) return { err: new Error('is repeatable, wrap it in an array: [value]') };
 
 	if (value.length === 0) return { err: new Error('holds no values, omit it instead') };
 

todo.md

@@ -197,6 +197,13 @@ and is also what the panel ranked hardest — two methods, one answer.
 
 ### Correctness, ahead of everything below
 
+- [ ] **Type each known TLV's value by its tag, on read and on write, before 0.6.0 is cut.** Every
+      `tagValue` is `TlvValue`, so `{ callback_num: { tagValue: buf } }` compiles and is refused
+      only at runtime, and reading `receipted_message_id` has to narrow out arrays it can never
+      hold. Derive the types from the specs' own wire types and `multiple` flag. It has to land in
+      the same minor as the arrays, or narrowing the types is a second break. From the
+      product-owner review of #25.
+
 - [ ] **Settle what a repeated tag not marked `multiple` reads as, and pin it in a test.** A vendor
       tag or a known single-value tag a peer sends twice keeps the last occurrence and drops the
       rest silently, which goal 3 argues against; listing it would change every such tag's shape.