trgm_bugfix_v2.patch

*** a/contrib/pg_trgm/trgm_op.c
--- b/contrib/pg_trgm/trgm_op.c
***************
*** 272,278 **** get_wildcard_part(const char *str, int lenstr,
  	const char *beginword = str;
  	const char *endword;
  	char	   *s = buf;
! 	bool		in_wildcard_meta = false;
  	bool		in_escape = false;
  	int			clen;
  
--- 272,279 ----
  	const char *beginword = str;
  	const char *endword;
  	char	   *s = buf;
! 	bool		in_leading_wildcard_meta = false;
! 	bool		in_trailing_wildcard_meta = false;
  	bool		in_escape = false;
  	int			clen;
  
***************
*** 284,304 **** get_wildcard_part(const char *str, int lenstr,
  	{
  		if (in_escape)
  		{
- 			in_escape = false;
- 			in_wildcard_meta = false;
  			if (iswordchr(beginword))
  				break;
  		}
  		else
  		{
  			if (ISESCAPECHAR(beginword))
  				in_escape = true;
  			else if (ISWILDCARDCHAR(beginword))
! 				in_wildcard_meta = true;
  			else if (iswordchr(beginword))
  				break;
  			else
! 				in_wildcard_meta = false;
  		}
  		beginword += pg_mblen(beginword);
  	}
--- 285,305 ----
  	{
  		if (in_escape)
  		{
  			if (iswordchr(beginword))
  				break;
+ 			in_escape = false;
+ 			in_leading_wildcard_meta = false;
  		}
  		else
  		{
  			if (ISESCAPECHAR(beginword))
  				in_escape = true;
  			else if (ISWILDCARDCHAR(beginword))
! 				in_leading_wildcard_meta = true;
  			else if (iswordchr(beginword))
  				break;
  			else
! 				in_leading_wildcard_meta = false;
  		}
  		beginword += pg_mblen(beginword);
  	}
***************
*** 314,320 **** get_wildcard_part(const char *str, int lenstr,
  	 * meta-character.
  	 */
  	*charlen = 0;
! 	if (!in_wildcard_meta)
  	{
  		if (LPADDING > 0)
  		{
--- 315,321 ----
  	 * meta-character.
  	 */
  	*charlen = 0;
! 	if (!in_leading_wildcard_meta)
  	{
  		if (LPADDING > 0)
  		{
***************
*** 333,347 **** get_wildcard_part(const char *str, int lenstr,
  	 * string boundary.  Strip escapes during copy.
  	 */
  	endword = beginword;
- 	in_wildcard_meta = false;
- 	in_escape = false;
  	while (endword - str < lenstr)
  	{
  		clen = pg_mblen(endword);
  		if (in_escape)
  		{
  			in_escape = false;
- 			in_wildcard_meta = false;
  			if (iswordchr(endword))
  			{
  				memcpy(s, endword, clen);
--- 334,345 ----
***************
*** 349,355 **** get_wildcard_part(const char *str, int lenstr,
--- 347,361 ----
  				s += clen;
  			}
  			else
+ 			{
+ 				/*
+ 				 * Back up endword one byte if the last two characters are
+ 				 * an escape pair, so that subsequent get_wildcard_part will
+ 				 * restart from its escape character.
+ 				 */
+ 				endword--;
  				break;
+ 			}
  		}
  		else
  		{
***************
*** 357,363 **** get_wildcard_part(const char *str, int lenstr,
  				in_escape = true;
  			else if (ISWILDCARDCHAR(endword))
  			{
! 				in_wildcard_meta = true;
  				break;
  			}
  			else if (iswordchr(endword))
--- 363,369 ----
  				in_escape = true;
  			else if (ISWILDCARDCHAR(endword))
  			{
! 				in_trailing_wildcard_meta = true;
  				break;
  			}
  			else if (iswordchr(endword))
***************
*** 367,376 **** get_wildcard_part(const char *str, int lenstr,
  				s += clen;
  			}
  			else
- 			{
- 				in_wildcard_meta = false;
  				break;
- 			}
  		}
  		endword += clen;
  	}
--- 373,379 ----
***************
*** 379,385 **** get_wildcard_part(const char *str, int lenstr,
  	 * Add right padding spaces if last character wasn't wildcard
  	 * meta-character.
  	 */
! 	if (!in_wildcard_meta)
  	{
  		if (RPADDING > 0)
  		{
--- 382,388 ----
  	 * Add right padding spaces if last character wasn't wildcard
  	 * meta-character.
  	 */
! 	if (!in_trailing_wildcard_meta)
  	{
  		if (RPADDING > 0)
  		{