common/json_parse_simple: drop redundant and wrong json_str_to_u64()

The json_str_to_u64() function contains incorrect logic. It chops one character
off of the beginning and end of the JSMN token and then parses the remainder as
a u64, but JSMN_STRING tokens already do not include the enclosing quotation
marks, so json_str_to_u64() would actually parse the JSON string "1234" into
the integer 23. Oops! Also note that it would simply fail on all input strings
shorter than two characters since tok->end would wind up *before* tok->start.

Just drop the function entirely. It was only used in one place, and that place
explicitly doesn't care whether its input is a JSON number or a numeric string,
and it was already calling json_to_u64() as an alternative, and that function
already accepts both JSON strings and JSON numbers as input, so the call to
json_str_to_u64() would have been entirely redundant if it had been correct.

Changelog-Fixed: The `keysend` command no longer corrupts the type numbers of extra TLVs when they are specified as numeric strings longer than 2 digits.

common/json_param.c

@@ -986,8 +986,7 @@ struct command_result *param_extra_tlvs(struct command *cmd, const char *name,
 		/* Accept either bare ints as keys (not spec
 		 * compliant, but simpler), or ints in strings, which
 		 * are JSON spec compliant. */
-		if (!(json_str_to_u64(buffer, curr, &f->numtype) ||
+		if (!json_to_u64(buffer, curr, &f->numtype)) {
-		      json_to_u64(buffer, curr, &f->numtype))) {
 			return command_fail(
 			    cmd, JSONRPC2_INVALID_PARAMS,
 			    "\"%s\" is not a valid numeric TLV type.",

common/json_parse_simple.c

@@ -109,19 +109,6 @@ bool json_to_s64(const char *buffer, const jsmntok_t *tok, s64 *num)
 	return true;
 }
 
-bool json_str_to_u64(const char *buffer, const jsmntok_t *tok, u64 *num)
-{
-	jsmntok_t temp;
-	if (tok->type != JSMN_STRING)
-		return false;
-
-	temp = *tok;
-	temp.start += 1;
-	temp.end -= 1;
-
-	return json_to_u64(buffer, &temp, num);
-}
-
 bool json_to_double(const char *buffer, const jsmntok_t *tok, double *num)
 {
 	char *end;

common/json_parse_simple.h

@@ -42,10 +42,6 @@ bool json_to_u64(const char *buffer, const jsmntok_t *tok, u64 *num);
 /* Extract signed 64 bit integer from this (may be a string, or a number literal) */
 bool json_to_s64(const char *buffer, const jsmntok_t *tok, s64 *num);
 
-/* Extract number from string. The number must be the entirety of the
- * string between the '"' */
-bool json_str_to_u64(const char *buffer, const jsmntok_t *tok, u64 *num);
-
 /* Extract number from this (may be a string, or a number literal) */
 bool json_to_u32(const char *buffer, const jsmntok_t *tok, u32 *num);