Rename my_snprintf’s %uE to %iE

… and delete `%uU` (just use `%d` for that) The follow-up #3360 discovered `%M` usages that suggest that it was designed for `errno` and similar **signed** `int` (“errno_t”) variables. Besides convenience, if the old `%M` read a `signed int`, so should the new version to maintain compatibility. I only added `%iE` (no `%dE`) to keep the new suffix mechanics away from the popular `%d`. Beïng synonyms (originally), this decision on preserving `%d` also saves the need for `%iI`/`%dD`.

Author: ParadoxV5

include/mysql/service_my_snprintf.h

@@ -67,21 +67,22 @@
  <precision> bytes without terminating on any '\0's in the sequence.
  The default <precision> when it's unspecified is not defined.
 
- Format 'uE'
- treats the argument as an errno number. It prints this number, a space,
- then its corresponding error message in double quotes. In other words:
- printf("%uE", n) === printf("%d \"%sT\"", n, strerror(n))
-
  Format 'sT'
  replaces the end of the printed string with "..." if it was truncated.
 
- Format 'sS' and 'uU'
- are synonyms of 's' and 'u' respectively. They are escapes that avoid
+ Format 'sS'
+ is a synonym for 's'. It's an escape that avoid
  consuming the following plain char as one of the above extension suffixes.
- Example: "Data size: %uUEiB"
+ Example: "Data Class: %sSType"
+
+ Format 'iE'
+ treats the argument as an errno number. It prints this number, a space,
+ then its corresponding error message in double quotes. In other words:
+ printf("%iE", n) === printf("%i \"%sT\"", n, strerror(n))
+ Format 'dE' has no effect. Therefore, to escape '%iE', use '%dE' instead.
 
  Unrecognized and multiple suffixes are not parsed;
- for example, both "%sTQ" and "%uQ" will print a literal 'Q'.
+ for example, both "%sTQ" and "%iQ" will suffix with a literal 'Q'.
 */
 
 #ifdef __cplusplus

strings/my_vsnprintf.c

@@ -586,16 +586,12 @@ static char *process_args(CHARSET_INFO *cs, char *to, char *end,
  /* Integer parameter */
  longlong larg= args_arr[print_arr[i].arg_idx].longlong_arg;
  my_bool suffix_e= arg_type == 'M';
- if (arg_type == 'u')
- switch (*print_arr[idx].begin) // look at the start of the next chunk
- {
- case 'E':
- suffix_e= TRUE;
- // fall-through
- case 'U': // escape
- ++print_arr[idx].begin; // roll forward to consume the char
- break;
- }
+ // look at the start of the next chunk
+ if (arg_type == 'i' && *print_arr[i].begin == 'E')
+ {
+ suffix_e= TRUE;
+ ++print_arr[i].begin; // roll forward to consume the char
+ }
  if (suffix_e)
  {
  const char *real_end;
@@ -807,16 +803,11 @@ size_t my_vsnprintf_ex(CHARSET_INFO *cs, char *to, size_t n,
  larg= va_arg(ap, int);
  else
  larg= va_arg(ap, uint);
- if (arg_type == 'u')
- switch (fmt[1]) // look-ahead
- {
- case 'E':
- suffix_e= TRUE;
- // fall-through
- case 'U': // escape
- ++fmt;
- break;
- }
+ if (arg_type == 'i' && fmt[1] == 'E') // look-ahead
+ {
+ suffix_e= TRUE;
+ ++fmt;
+ }
  if (suffix_e)
  {
  const char *real_end= MY_MIN(to + width, end);

unittest/mysys/my_vsnprintf-t.c

@@ -113,9 +113,6 @@ int main(void)
 
  test1("MariaDB extension escape sS works",
  "MariaDB extension escape sS %sS", "works");
- test1("MariaDB extension escape uU 2",
- "MariaDB extension escape uU %uU", 2);
-
  test1("MariaDB extension sQ works: `abcd` `op``q`",
  "MariaDB extension sQ works: %sQ %.4sQ", "abcd", "op`qrst");
 
@@ -131,21 +128,24 @@ int main(void)
  }
 
  {
- // Test that %uE works
+ // Test that %iE works
  const char *results[]=
  {
- "MariaDB extension uE works: 1 \"Operation not permitted\"", // Linux
- "MariaDB extension uE works: 1 \"Not owner\"", // Solaris
+ "MariaDB extension iE works: 1 \"Operation not permitted\"", // Linux
+ "MariaDB extension iE works: 1 \"Not owner\"", // Solaris
  NullS
  };
- test_many(results, "MariaDB extension uE works: %uE", 1);
+ test_many(results, "MariaDB extension iE works: %iE", 1);
  }
- test1("uE with 0 errno: 0 \"Internal error/check (Not system error)\"",
- "uE with 0 errno: %uE", 0);
- test1("uE with width: <0 \"Internal error...>",
- "uE with width: <%.20uE>", 0);
- test_w_len("uE with small buf: 0 \"..",
- 25, "uE with small buf: %uE", 0);
+ test1("iE with 0 errno: 0 \"Internal error/check (Not system error)\"",
+ "iE with 0 errno: %iE", 0);
+ test1("iE with width: <0 \"Internal error...>",
+ "iE with width: <%.20iE>", 0);
+ test_w_len("iE with small buf: 0 \"..",
+ 25, "iE with small buf: %iE", 0);
+
+ test1("MariaDB extension dE DOESN'T work: 0E",
+ "MariaDB extension dE DOESN'T work: %dE", 0);
 
  test1("MariaDB extension sT works: <abcd> <op...>",
  "MariaDB extension sT %sT: <%.5sT> <%.5sT>", "works", "abcd", "opqrst");