Remove dead encoding-conversion functions.

The code for conversions SQL_ASCII <-> MULE_INTERNAL and
SQL_ASCII <-> UTF8 was unreachable, because we long ago changed
the wrapper functions pg_do_encoding_conversion() et al so that
they have hard-wired behaviors for conversions involving SQL_ASCII.
(At least some of those fast paths date back to 2002, though it
looks like we may not have been totally consistent about this until
later.)  Given the lack of complaints, nobody is dissatisfied with
this state of affairs.  Hence, let's just remove the unreachable code.

Also, change CREATE CONVERSION so that it rejects attempts to
define such conversions.  Since we consider that SQL_ASCII represents
lack of knowledge about the encoding in use, such a conversion would
be semantically dubious even if it were reachable.

Adjust a couple of regression test cases that had randomly decided
to rely on these conversion functions rather than any other ones.

Discussion: https://postgr.es/m/[email protected]

4 files changed, 8 insertions, 8 deletions

diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index d621f61c623..3578b8009b8 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -2713,7 +2713,7 @@ as 'select $1.f1 is not distinct from $2.f1 and $1.f2 is not distinct from $2.f2
 create operator alter1.=(procedure = alter1.same, leftarg  = alter1.ctype, rightarg = alter1.ctype);
 create operator class alter1.ctype_hash_ops default for type alter1.ctype using hash as
   operator 1 alter1.=(alter1.ctype, alter1.ctype);
-create conversion alter1.ascii_to_utf8 for 'sql_ascii' to 'utf8' from ascii_to_utf8;
+create conversion alter1.latin1_to_utf8 for 'latin1' to 'utf8' from iso8859_1_to_utf8;
 create text search parser alter1.prs(start = prsd_start, gettoken = prsd_nexttoken, end = prsd_end, lextypes = prsd_lextype);
 create text search configuration alter1.cfg(parser = alter1.prs);
 create text search template alter1.tmpl(init = dsimple_init, lexize = dsimple_lexize);
@@ -2731,7 +2731,7 @@ alter operator alter1.=(alter1.ctype, alter1.ctype) set schema alter2;
 alter function alter1.same(alter1.ctype, alter1.ctype) set schema alter2;
 alter type alter1.ctype set schema alter1; -- no-op, same schema
 alter type alter1.ctype set schema alter2;
-alter conversion alter1.ascii_to_utf8 set schema alter2;
+alter conversion alter1.latin1_to_utf8 set schema alter2;
 alter text search parser alter1.prs set schema alter2;
 alter text search configuration alter1.cfg set schema alter2;
 alter text search template alter1.tmpl set schema alter2;
@@ -2775,7 +2775,7 @@ drop cascades to type alter2.ctype
 drop cascades to function alter2.same(alter2.ctype,alter2.ctype)
 drop cascades to operator alter2.=(alter2.ctype,alter2.ctype)
 drop cascades to operator family alter2.ctype_hash_ops for access method hash
-drop cascades to conversion alter2.ascii_to_utf8
+drop cascades to conversion alter2.latin1_to_utf8
 drop cascades to text search parser alter2.prs
 drop cascades to text search configuration alter2.cfg
 drop cascades to text search template alter2.tmpl
diff --git a/src/test/regress/expected/object_address.out b/src/test/regress/expected/object_address.out
index de75b9a7dd3..cdbde295025 100644
--- a/src/test/regress/expected/object_address.out
+++ b/src/test/regress/expected/object_address.out
@@ -394,7 +394,7 @@ WITH objects (type, name, args) AS (VALUES
 				('collation', '{default}', '{}'),
 				('table constraint', '{addr_nsp, gentable, a_chk}', '{}'),
 				('domain constraint', '{addr_nsp.gendomain}', '{domconstr}'),
-				('conversion', '{pg_catalog, ascii_to_mic}', '{}'),
+				('conversion', '{pg_catalog, koi8_r_to_mic}', '{}'),
 				('default value', '{addr_nsp, gentable, b}', '{}'),
 				('language', '{plpgsql}', '{}'),
 				-- large object
@@ -468,7 +468,7 @@ SELECT (pg_identify_object(addr1.classid, addr1.objid, addr1.objsubid)).*,
  cast                      |            |                   | (bigint AS integer)                                                  | t
  table constraint          | addr_nsp   |                   | a_chk on addr_nsp.gentable                                           | t
  domain constraint         | addr_nsp   |                   | domconstr on addr_nsp.gendomain                                      | t
- conversion                | pg_catalog | ascii_to_mic      | pg_catalog.ascii_to_mic                                              | t
+ conversion                | pg_catalog | koi8_r_to_mic     | pg_catalog.koi8_r_to_mic                                             | t
  language                  |            | plpgsql           | plpgsql                                                              | t
  schema                    |            | addr_nsp          | addr_nsp                                                             | t
  operator class            | pg_catalog | int4_ops          | pg_catalog.int4_ops USING btree                                      | t
diff --git a/src/test/regress/sql/alter_table.sql b/src/test/regress/sql/alter_table.sql
index 8016f8a823a..99af0b851b3 100644
--- a/src/test/regress/sql/alter_table.sql
+++ b/src/test/regress/sql/alter_table.sql
@@ -1735,7 +1735,7 @@ create operator alter1.=(procedure = alter1.same, leftarg  = alter1.ctype, right
 create operator class alter1.ctype_hash_ops default for type alter1.ctype using hash as
   operator 1 alter1.=(alter1.ctype, alter1.ctype);
 
-create conversion alter1.ascii_to_utf8 for 'sql_ascii' to 'utf8' from ascii_to_utf8;
+create conversion alter1.latin1_to_utf8 for 'latin1' to 'utf8' from iso8859_1_to_utf8;
 
 create text search parser alter1.prs(start = prsd_start, gettoken = prsd_nexttoken, end = prsd_end, lextypes = prsd_lextype);
 create text search configuration alter1.cfg(parser = alter1.prs);
@@ -1756,7 +1756,7 @@ alter operator alter1.=(alter1.ctype, alter1.ctype) set schema alter2;
 alter function alter1.same(alter1.ctype, alter1.ctype) set schema alter2;
 alter type alter1.ctype set schema alter1; -- no-op, same schema
 alter type alter1.ctype set schema alter2;
-alter conversion alter1.ascii_to_utf8 set schema alter2;
+alter conversion alter1.latin1_to_utf8 set schema alter2;
 alter text search parser alter1.prs set schema alter2;
 alter text search configuration alter1.cfg set schema alter2;
 alter text search template alter1.tmpl set schema alter2;
diff --git a/src/test/regress/sql/object_address.sql b/src/test/regress/sql/object_address.sql
index bd94cd654b5..725bc39b50b 100644
--- a/src/test/regress/sql/object_address.sql
+++ b/src/test/regress/sql/object_address.sql
@@ -164,7 +164,7 @@ WITH objects (type, name, args) AS (VALUES
 				('collation', '{default}', '{}'),
 				('table constraint', '{addr_nsp, gentable, a_chk}', '{}'),
 				('domain constraint', '{addr_nsp.gendomain}', '{domconstr}'),
-				('conversion', '{pg_catalog, ascii_to_mic}', '{}'),
+				('conversion', '{pg_catalog, koi8_r_to_mic}', '{}'),
 				('default value', '{addr_nsp, gentable, b}', '{}'),
 				('language', '{plpgsql}', '{}'),
 				-- large object