Add 'noError' argument to encoding conversion functions.

With the 'noError' argument, you can try to convert a buffer without
knowing the character boundaries beforehand. The functions now need to
return the number of input bytes successfully converted.

This is is a backwards-incompatible change, if you have created a custom
encoding conversion with CREATE CONVERSION. This adds a check to
pg_upgrade for that, refusing the upgrade if there are any user-defined
encoding conversions. Custom conversions are very rare, there are no
commonly used extensions that I know of that uses that feature. No other
objects can depend on conversions, so if you do have one, you can fairly
easily drop it before upgrading, and recreate it after the upgrade with
an updated version.

Add regression tests for built-in encoding conversions. This doesn't cover
every conversion, but it covers all the internal functions in conv.c that
are used to implement the conversions.

Reviewed-by: John Naylor
Discussion: https://www.postgresql.org/message-id/e7861509-3960-538a-9025-b75a61188e01%40iki.fi

3 files changed, 188 insertions, 181 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 489f5be427f..6a61c8f64f0 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202103291
+#define CATALOG_VERSION_NO	202104011
 
 #endif
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index bfb89e0575d..69ffd0c3f4d 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -10914,388 +10914,388 @@
 # conversion functions
 { oid => '4302',
   descr => 'internal conversion function for KOI8R to MULE_INTERNAL',
-  proname => 'koi8r_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'koi8r_to_mic',
+  proname => 'koi8r_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'koi8r_to_mic',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4303',
   descr => 'internal conversion function for MULE_INTERNAL to KOI8R',
-  proname => 'mic_to_koi8r', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_koi8r',
+  proname => 'mic_to_koi8r', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_koi8r',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4304',
   descr => 'internal conversion function for ISO-8859-5 to MULE_INTERNAL',
-  proname => 'iso_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'iso_to_mic',
+  proname => 'iso_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'iso_to_mic',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4305',
   descr => 'internal conversion function for MULE_INTERNAL to ISO-8859-5',
-  proname => 'mic_to_iso', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_iso',
+  proname => 'mic_to_iso', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_iso',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4306',
   descr => 'internal conversion function for WIN1251 to MULE_INTERNAL',
-  proname => 'win1251_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win1251_to_mic',
+  proname => 'win1251_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win1251_to_mic',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4307',
   descr => 'internal conversion function for MULE_INTERNAL to WIN1251',
-  proname => 'mic_to_win1251', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_win1251',
+  proname => 'mic_to_win1251', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_win1251',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4308',
   descr => 'internal conversion function for WIN866 to MULE_INTERNAL',
-  proname => 'win866_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win866_to_mic',
+  proname => 'win866_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win866_to_mic',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4309',
   descr => 'internal conversion function for MULE_INTERNAL to WIN866',
-  proname => 'mic_to_win866', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_win866',
+  proname => 'mic_to_win866', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_win866',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4310', descr => 'internal conversion function for KOI8R to WIN1251',
-  proname => 'koi8r_to_win1251', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'koi8r_to_win1251', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'koi8r_to_win1251', probin => '$libdir/cyrillic_and_mic' },
 { oid => '4311', descr => 'internal conversion function for WIN1251 to KOI8R',
-  proname => 'win1251_to_koi8r', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'win1251_to_koi8r', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'win1251_to_koi8r', probin => '$libdir/cyrillic_and_mic' },
 { oid => '4312', descr => 'internal conversion function for KOI8R to WIN866',
-  proname => 'koi8r_to_win866', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'koi8r_to_win866',
+  proname => 'koi8r_to_win866', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'koi8r_to_win866',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4313', descr => 'internal conversion function for WIN866 to KOI8R',
-  proname => 'win866_to_koi8r', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win866_to_koi8r',
+  proname => 'win866_to_koi8r', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win866_to_koi8r',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4314',
   descr => 'internal conversion function for WIN866 to WIN1251',
-  proname => 'win866_to_win1251', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'win866_to_win1251', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'win866_to_win1251', probin => '$libdir/cyrillic_and_mic' },
 { oid => '4315',
   descr => 'internal conversion function for WIN1251 to WIN866',
-  proname => 'win1251_to_win866', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'win1251_to_win866', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'win1251_to_win866', probin => '$libdir/cyrillic_and_mic' },
 { oid => '4316',
   descr => 'internal conversion function for ISO-8859-5 to KOI8R',
-  proname => 'iso_to_koi8r', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'iso_to_koi8r',
+  proname => 'iso_to_koi8r', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'iso_to_koi8r',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4317',
   descr => 'internal conversion function for KOI8R to ISO-8859-5',
-  proname => 'koi8r_to_iso', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'koi8r_to_iso',
+  proname => 'koi8r_to_iso', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'koi8r_to_iso',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4318',
   descr => 'internal conversion function for ISO-8859-5 to WIN1251',
-  proname => 'iso_to_win1251', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'iso_to_win1251',
+  proname => 'iso_to_win1251', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'iso_to_win1251',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4319',
   descr => 'internal conversion function for WIN1251 to ISO-8859-5',
-  proname => 'win1251_to_iso', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win1251_to_iso',
+  proname => 'win1251_to_iso', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win1251_to_iso',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4320',
   descr => 'internal conversion function for ISO-8859-5 to WIN866',
-  proname => 'iso_to_win866', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'iso_to_win866',
+  proname => 'iso_to_win866', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'iso_to_win866',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4321',
   descr => 'internal conversion function for WIN866 to ISO-8859-5',
-  proname => 'win866_to_iso', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win866_to_iso',
+  proname => 'win866_to_iso', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win866_to_iso',
   probin => '$libdir/cyrillic_and_mic' },
 { oid => '4322',
   descr => 'internal conversion function for EUC_CN to MULE_INTERNAL',
-  proname => 'euc_cn_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_cn_to_mic',
+  proname => 'euc_cn_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_cn_to_mic',
   probin => '$libdir/euc_cn_and_mic' },
 { oid => '4323',
   descr => 'internal conversion function for MULE_INTERNAL to EUC_CN',
-  proname => 'mic_to_euc_cn', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_euc_cn',
+  proname => 'mic_to_euc_cn', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_euc_cn',
   probin => '$libdir/euc_cn_and_mic' },
 { oid => '4324', descr => 'internal conversion function for EUC_JP to SJIS',
-  proname => 'euc_jp_to_sjis', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_jp_to_sjis',
+  proname => 'euc_jp_to_sjis', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_jp_to_sjis',
   probin => '$libdir/euc_jp_and_sjis' },
 { oid => '4325', descr => 'internal conversion function for SJIS to EUC_JP',
-  proname => 'sjis_to_euc_jp', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'sjis_to_euc_jp',
+  proname => 'sjis_to_euc_jp', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'sjis_to_euc_jp',
   probin => '$libdir/euc_jp_and_sjis' },
 { oid => '4326',
   descr => 'internal conversion function for EUC_JP to MULE_INTERNAL',
-  proname => 'euc_jp_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_jp_to_mic',
+  proname => 'euc_jp_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_jp_to_mic',
   probin => '$libdir/euc_jp_and_sjis' },
 { oid => '4327',
   descr => 'internal conversion function for SJIS to MULE_INTERNAL',
-  proname => 'sjis_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'sjis_to_mic',
+  proname => 'sjis_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'sjis_to_mic',
   probin => '$libdir/euc_jp_and_sjis' },
 { oid => '4328',
   descr => 'internal conversion function for MULE_INTERNAL to EUC_JP',
-  proname => 'mic_to_euc_jp', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_euc_jp',
+  proname => 'mic_to_euc_jp', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_euc_jp',
   probin => '$libdir/euc_jp_and_sjis' },
 { oid => '4329',
   descr => 'internal conversion function for MULE_INTERNAL to SJIS',
-  proname => 'mic_to_sjis', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_sjis',
+  proname => 'mic_to_sjis', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_sjis',
   probin => '$libdir/euc_jp_and_sjis' },
 { oid => '4330',
   descr => 'internal conversion function for EUC_KR to MULE_INTERNAL',
-  proname => 'euc_kr_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_kr_to_mic',
+  proname => 'euc_kr_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_kr_to_mic',
   probin => '$libdir/euc_kr_and_mic' },
 { oid => '4331',
   descr => 'internal conversion function for MULE_INTERNAL to EUC_KR',
-  proname => 'mic_to_euc_kr', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_euc_kr',
+  proname => 'mic_to_euc_kr', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_euc_kr',
   probin => '$libdir/euc_kr_and_mic' },
 { oid => '4332', descr => 'internal conversion function for EUC_TW to BIG5',
-  proname => 'euc_tw_to_big5', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_tw_to_big5',
+  proname => 'euc_tw_to_big5', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_tw_to_big5',
   probin => '$libdir/euc_tw_and_big5' },
 { oid => '4333', descr => 'internal conversion function for BIG5 to EUC_TW',
-  proname => 'big5_to_euc_tw', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'big5_to_euc_tw',
+  proname => 'big5_to_euc_tw', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'big5_to_euc_tw',
   probin => '$libdir/euc_tw_and_big5' },
 { oid => '4334',
   descr => 'internal conversion function for EUC_TW to MULE_INTERNAL',
-  proname => 'euc_tw_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_tw_to_mic',
+  proname => 'euc_tw_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_tw_to_mic',
   probin => '$libdir/euc_tw_and_big5' },
 { oid => '4335',
   descr => 'internal conversion function for BIG5 to MULE_INTERNAL',
-  proname => 'big5_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'big5_to_mic',
+  proname => 'big5_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'big5_to_mic',
   probin => '$libdir/euc_tw_and_big5' },
 { oid => '4336',
   descr => 'internal conversion function for MULE_INTERNAL to EUC_TW',
-  proname => 'mic_to_euc_tw', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_euc_tw',
+  proname => 'mic_to_euc_tw', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_euc_tw',
   probin => '$libdir/euc_tw_and_big5' },
 { oid => '4337',
   descr => 'internal conversion function for MULE_INTERNAL to BIG5',
-  proname => 'mic_to_big5', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_big5',
+  proname => 'mic_to_big5', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_big5',
   probin => '$libdir/euc_tw_and_big5' },
 { oid => '4338',
   descr => 'internal conversion function for LATIN2 to MULE_INTERNAL',
-  proname => 'latin2_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'latin2_to_mic',
+  proname => 'latin2_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'latin2_to_mic',
   probin => '$libdir/latin2_and_win1250' },
 { oid => '4339',
   descr => 'internal conversion function for MULE_INTERNAL to LATIN2',
-  proname => 'mic_to_latin2', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_latin2',
+  proname => 'mic_to_latin2', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_latin2',
   probin => '$libdir/latin2_and_win1250' },
 { oid => '4340',
   descr => 'internal conversion function for WIN1250 to MULE_INTERNAL',
-  proname => 'win1250_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win1250_to_mic',
+  proname => 'win1250_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win1250_to_mic',
   probin => '$libdir/latin2_and_win1250' },
 { oid => '4341',
   descr => 'internal conversion function for MULE_INTERNAL to WIN1250',
-  proname => 'mic_to_win1250', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_win1250',
+  proname => 'mic_to_win1250', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_win1250',
   probin => '$libdir/latin2_and_win1250' },
 { oid => '4342',
   descr => 'internal conversion function for LATIN2 to WIN1250',
-  proname => 'latin2_to_win1250', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'latin2_to_win1250', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'latin2_to_win1250', probin => '$libdir/latin2_and_win1250' },
 { oid => '4343',
   descr => 'internal conversion function for WIN1250 to LATIN2',
-  proname => 'win1250_to_latin2', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'win1250_to_latin2', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'win1250_to_latin2', probin => '$libdir/latin2_and_win1250' },
 { oid => '4344',
   descr => 'internal conversion function for LATIN1 to MULE_INTERNAL',
-  proname => 'latin1_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'latin1_to_mic',
+  proname => 'latin1_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'latin1_to_mic',
   probin => '$libdir/latin_and_mic' },
 { oid => '4345',
   descr => 'internal conversion function for MULE_INTERNAL to LATIN1',
-  proname => 'mic_to_latin1', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_latin1',
+  proname => 'mic_to_latin1', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_latin1',
   probin => '$libdir/latin_and_mic' },
 { oid => '4346',
   descr => 'internal conversion function for LATIN3 to MULE_INTERNAL',
-  proname => 'latin3_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'latin3_to_mic',
+  proname => 'latin3_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'latin3_to_mic',
   probin => '$libdir/latin_and_mic' },
 { oid => '4347',
   descr => 'internal conversion function for MULE_INTERNAL to LATIN3',
-  proname => 'mic_to_latin3', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_latin3',
+  proname => 'mic_to_latin3', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_latin3',
   probin => '$libdir/latin_and_mic' },
 { oid => '4348',
   descr => 'internal conversion function for LATIN4 to MULE_INTERNAL',
-  proname => 'latin4_to_mic', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'latin4_to_mic',
+  proname => 'latin4_to_mic', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'latin4_to_mic',
   probin => '$libdir/latin_and_mic' },
 { oid => '4349',
   descr => 'internal conversion function for MULE_INTERNAL to LATIN4',
-  proname => 'mic_to_latin4', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'mic_to_latin4',
+  proname => 'mic_to_latin4', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'mic_to_latin4',
   probin => '$libdir/latin_and_mic' },
 { oid => '4352', descr => 'internal conversion function for BIG5 to UTF8',
-  proname => 'big5_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'big5_to_utf8',
+  proname => 'big5_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'big5_to_utf8',
   probin => '$libdir/utf8_and_big5' },
 { oid => '4353', descr => 'internal conversion function for UTF8 to BIG5',
-  proname => 'utf8_to_big5', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_big5',
+  proname => 'utf8_to_big5', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_big5',
   probin => '$libdir/utf8_and_big5' },
 { oid => '4354', descr => 'internal conversion function for UTF8 to KOI8R',
-  proname => 'utf8_to_koi8r', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_koi8r',
+  proname => 'utf8_to_koi8r', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_koi8r',
   probin => '$libdir/utf8_and_cyrillic' },
 { oid => '4355', descr => 'internal conversion function for KOI8R to UTF8',
-  proname => 'koi8r_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'koi8r_to_utf8',
+  proname => 'koi8r_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'koi8r_to_utf8',
   probin => '$libdir/utf8_and_cyrillic' },
 { oid => '4356', descr => 'internal conversion function for UTF8 to KOI8U',
-  proname => 'utf8_to_koi8u', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_koi8u',
+  proname => 'utf8_to_koi8u', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_koi8u',
   probin => '$libdir/utf8_and_cyrillic' },
 { oid => '4357', descr => 'internal conversion function for KOI8U to UTF8',
-  proname => 'koi8u_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'koi8u_to_utf8',
+  proname => 'koi8u_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'koi8u_to_utf8',
   probin => '$libdir/utf8_and_cyrillic' },
 { oid => '4358', descr => 'internal conversion function for UTF8 to WIN',
-  proname => 'utf8_to_win', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_win',
+  proname => 'utf8_to_win', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_win',
   probin => '$libdir/utf8_and_win' },
 { oid => '4359', descr => 'internal conversion function for WIN to UTF8',
-  proname => 'win_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'win_to_utf8',
+  proname => 'win_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'win_to_utf8',
   probin => '$libdir/utf8_and_win' },
 { oid => '4360', descr => 'internal conversion function for EUC_CN to UTF8',
-  proname => 'euc_cn_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_cn_to_utf8',
+  proname => 'euc_cn_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_cn_to_utf8',
   probin => '$libdir/utf8_and_euc_cn' },
 { oid => '4361', descr => 'internal conversion function for UTF8 to EUC_CN',
-  proname => 'utf8_to_euc_cn', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_euc_cn',
+  proname => 'utf8_to_euc_cn', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_euc_cn',
   probin => '$libdir/utf8_and_euc_cn' },
 { oid => '4362', descr => 'internal conversion function for EUC_JP to UTF8',
-  proname => 'euc_jp_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_jp_to_utf8',
+  proname => 'euc_jp_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_jp_to_utf8',
   probin => '$libdir/utf8_and_euc_jp' },
 { oid => '4363', descr => 'internal conversion function for UTF8 to EUC_JP',
-  proname => 'utf8_to_euc_jp', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_euc_jp',
+  proname => 'utf8_to_euc_jp', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_euc_jp',
   probin => '$libdir/utf8_and_euc_jp' },
 { oid => '4364', descr => 'internal conversion function for EUC_KR to UTF8',
-  proname => 'euc_kr_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_kr_to_utf8',
+  proname => 'euc_kr_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_kr_to_utf8',
   probin => '$libdir/utf8_and_euc_kr' },
 { oid => '4365', descr => 'internal conversion function for UTF8 to EUC_KR',
-  proname => 'utf8_to_euc_kr', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_euc_kr',
+  proname => 'utf8_to_euc_kr', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_euc_kr',
   probin => '$libdir/utf8_and_euc_kr' },
 { oid => '4366', descr => 'internal conversion function for EUC_TW to UTF8',
-  proname => 'euc_tw_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'euc_tw_to_utf8',
+  proname => 'euc_tw_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'euc_tw_to_utf8',
   probin => '$libdir/utf8_and_euc_tw' },
 { oid => '4367', descr => 'internal conversion function for UTF8 to EUC_TW',
-  proname => 'utf8_to_euc_tw', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_euc_tw',
+  proname => 'utf8_to_euc_tw', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_euc_tw',
   probin => '$libdir/utf8_and_euc_tw' },
 { oid => '4368', descr => 'internal conversion function for GB18030 to UTF8',
-  proname => 'gb18030_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'gb18030_to_utf8',
+  proname => 'gb18030_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'gb18030_to_utf8',
   probin => '$libdir/utf8_and_gb18030' },
 { oid => '4369', descr => 'internal conversion function for UTF8 to GB18030',
-  proname => 'utf8_to_gb18030', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_gb18030',
+  proname => 'utf8_to_gb18030', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_gb18030',
   probin => '$libdir/utf8_and_gb18030' },
 { oid => '4370', descr => 'internal conversion function for GBK to UTF8',
-  proname => 'gbk_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'gbk_to_utf8',
+  proname => 'gbk_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'gbk_to_utf8',
   probin => '$libdir/utf8_and_gbk' },
 { oid => '4371', descr => 'internal conversion function for UTF8 to GBK',
-  proname => 'utf8_to_gbk', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_gbk',
+  proname => 'utf8_to_gbk', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_gbk',
   probin => '$libdir/utf8_and_gbk' },
 { oid => '4372',
   descr => 'internal conversion function for UTF8 to ISO-8859 2-16',
-  proname => 'utf8_to_iso8859', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_iso8859',
+  proname => 'utf8_to_iso8859', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_iso8859',
   probin => '$libdir/utf8_and_iso8859' },
 { oid => '4373',
   descr => 'internal conversion function for ISO-8859 2-16 to UTF8',
-  proname => 'iso8859_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'iso8859_to_utf8',
+  proname => 'iso8859_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'iso8859_to_utf8',
   probin => '$libdir/utf8_and_iso8859' },
 { oid => '4374', descr => 'internal conversion function for LATIN1 to UTF8',
-  proname => 'iso8859_1_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'iso8859_1_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'iso8859_1_to_utf8', probin => '$libdir/utf8_and_iso8859_1' },
 { oid => '4375', descr => 'internal conversion function for UTF8 to LATIN1',
-  proname => 'utf8_to_iso8859_1', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'utf8_to_iso8859_1', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'utf8_to_iso8859_1', probin => '$libdir/utf8_and_iso8859_1' },
 { oid => '4376', descr => 'internal conversion function for JOHAB to UTF8',
-  proname => 'johab_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'johab_to_utf8',
+  proname => 'johab_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'johab_to_utf8',
   probin => '$libdir/utf8_and_johab' },
 { oid => '4377', descr => 'internal conversion function for UTF8 to JOHAB',
-  proname => 'utf8_to_johab', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_johab',
+  proname => 'utf8_to_johab', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_johab',
   probin => '$libdir/utf8_and_johab' },
 { oid => '4378', descr => 'internal conversion function for SJIS to UTF8',
-  proname => 'sjis_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'sjis_to_utf8',
+  proname => 'sjis_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'sjis_to_utf8',
   probin => '$libdir/utf8_and_sjis' },
 { oid => '4379', descr => 'internal conversion function for UTF8 to SJIS',
-  proname => 'utf8_to_sjis', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_sjis',
+  proname => 'utf8_to_sjis', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_sjis',
   probin => '$libdir/utf8_and_sjis' },
 { oid => '4380', descr => 'internal conversion function for UHC to UTF8',
-  proname => 'uhc_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'uhc_to_utf8',
+  proname => 'uhc_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'uhc_to_utf8',
   probin => '$libdir/utf8_and_uhc' },
 { oid => '4381', descr => 'internal conversion function for UTF8 to UHC',
-  proname => 'utf8_to_uhc', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4', prosrc => 'utf8_to_uhc',
+  proname => 'utf8_to_uhc', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool', prosrc => 'utf8_to_uhc',
   probin => '$libdir/utf8_and_uhc' },
 { oid => '4382',
   descr => 'internal conversion function for EUC_JIS_2004 to UTF8',
-  proname => 'euc_jis_2004_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'euc_jis_2004_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'euc_jis_2004_to_utf8', probin => '$libdir/utf8_and_euc2004' },
 { oid => '4383',
   descr => 'internal conversion function for UTF8 to EUC_JIS_2004',
-  proname => 'utf8_to_euc_jis_2004', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'utf8_to_euc_jis_2004', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'utf8_to_euc_jis_2004', probin => '$libdir/utf8_and_euc2004' },
 { oid => '4384',
   descr => 'internal conversion function for SHIFT_JIS_2004 to UTF8',
-  proname => 'shift_jis_2004_to_utf8', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'shift_jis_2004_to_utf8', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'shift_jis_2004_to_utf8', probin => '$libdir/utf8_and_sjis2004' },
 { oid => '4385',
   descr => 'internal conversion function for UTF8 to SHIFT_JIS_2004',
-  proname => 'utf8_to_shift_jis_2004', prolang => 'c', prorettype => 'void',
-  proargtypes => 'int4 int4 cstring internal int4',
+  proname => 'utf8_to_shift_jis_2004', prolang => 'c', prorettype => 'int4',
+  proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'utf8_to_shift_jis_2004', probin => '$libdir/utf8_and_sjis2004' },
 { oid => '4386',
   descr => 'internal conversion function for EUC_JIS_2004 to SHIFT_JIS_2004',
   proname => 'euc_jis_2004_to_shift_jis_2004', prolang => 'c',
-  prorettype => 'void', proargtypes => 'int4 int4 cstring internal int4',
+  prorettype => 'int4', proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'euc_jis_2004_to_shift_jis_2004',
   probin => '$libdir/euc2004_sjis2004' },
 { oid => '4387',
   descr => 'internal conversion function for SHIFT_JIS_2004 to EUC_JIS_2004',
   proname => 'shift_jis_2004_to_euc_jis_2004', prolang => 'c',
-  prorettype => 'void', proargtypes => 'int4 int4 cstring internal int4',
+  prorettype => 'int4', proargtypes => 'int4 int4 cstring internal int4 bool',
   prosrc => 'shift_jis_2004_to_euc_jis_2004',
   probin => '$libdir/euc2004_sjis2004' },
 
diff --git a/src/include/mb/pg_wchar.h b/src/include/mb/pg_wchar.h
index 64b22e4b0d4..a9aaff9e6dc 100644
--- a/src/include/mb/pg_wchar.h
+++ b/src/include/mb/pg_wchar.h
@@ -616,6 +616,12 @@ extern int	pg_bind_textdomain_codeset(const char *domainname);
 extern unsigned char *pg_do_encoding_conversion(unsigned char *src, int len,
 												int src_encoding,
 												int dest_encoding);
+extern int	pg_do_encoding_conversion_buf(Oid proc,
+										  int src_encoding,
+										  int dest_encoding,
+										  unsigned char *src, int srclen,
+										  unsigned char *dst, int dstlen,
+										  bool noError);
 
 extern char *pg_client_to_server(const char *s, int len);
 extern char *pg_server_to_client(const char *s, int len);
@@ -627,18 +633,18 @@ extern void pg_unicode_to_server(pg_wchar c, unsigned char *s);
 extern unsigned short BIG5toCNS(unsigned short big5, unsigned char *lc);
 extern unsigned short CNStoBIG5(unsigned short cns, unsigned char lc);
 
-extern void UtfToLocal(const unsigned char *utf, int len,
+extern int	UtfToLocal(const unsigned char *utf, int len,
 					   unsigned char *iso,
 					   const pg_mb_radix_tree *map,
 					   const pg_utf_to_local_combined *cmap, int cmapsize,
 					   utf_local_conversion_func conv_func,
-					   int encoding);
-extern void LocalToUtf(const unsigned char *iso, int len,
+					   int encoding, bool noError);
+extern int	LocalToUtf(const unsigned char *iso, int len,
 					   unsigned char *utf,
 					   const pg_mb_radix_tree *map,
 					   const pg_local_to_utf_combined *cmap, int cmapsize,
 					   utf_local_conversion_func conv_func,
-					   int encoding);
+					   int encoding, bool noError);
 
 extern bool pg_verifymbstr(const char *mbstr, int len, bool noError);
 extern bool pg_verify_mbstr(int encoding, const char *mbstr, int len,
@@ -656,18 +662,19 @@ extern void report_invalid_encoding(int encoding, const char *mbstr, int len) pg
 extern void report_untranslatable_char(int src_encoding, int dest_encoding,
 									   const char *mbstr, int len) pg_attribute_noreturn();
 
-extern void local2local(const unsigned char *l, unsigned char *p, int len,
-						int src_encoding, int dest_encoding, const unsigned char *tab);
-extern void latin2mic(const unsigned char *l, unsigned char *p, int len,
-					  int lc, int encoding);
-extern void mic2latin(const unsigned char *mic, unsigned char *p, int len,
-					  int lc, int encoding);
-extern void latin2mic_with_table(const unsigned char *l, unsigned char *p,
+extern int	local2local(const unsigned char *l, unsigned char *p, int len,
+						int src_encoding, int dest_encoding,
+						const unsigned char *tab, bool noError);
+extern int	latin2mic(const unsigned char *l, unsigned char *p, int len,
+					  int lc, int encoding, bool noError);
+extern int	mic2latin(const unsigned char *mic, unsigned char *p, int len,
+					  int lc, int encoding, bool noError);
+extern int	latin2mic_with_table(const unsigned char *l, unsigned char *p,
 								 int len, int lc, int encoding,
-								 const unsigned char *tab);
-extern void mic2latin_with_table(const unsigned char *mic, unsigned char *p,
+								 const unsigned char *tab, bool noError);
+extern int	mic2latin_with_table(const unsigned char *mic, unsigned char *p,
 								 int len, int lc, int encoding,
-								 const unsigned char *tab);
+								 const unsigned char *tab, bool noError);
 
 #ifdef WIN32
 extern WCHAR *pgwin32_message_to_UTF16(const char *str, int len, int *utf16len);