Allow ALTER TYPE to update an existing type's typsubscript value.

This is essential if we'd like to allow existing extension data types
to support subscripting in future, since dropping and recreating the
type isn't a practical thing for an extension upgrade script, and
direct manipulation of pg_type isn't a great answer either.

There was some discussion about also allowing alteration of typelem,
but it's less clear whether that's a good idea or not, so for now
I forebore.

Discussion: https://postgr.es/m/3724341.1607551174@sss.pgh.pa.us

diff --git a/doc/src/sgml/ref/alter_type.sgml b/doc/src/sgml/ref/alter_type.sgml
index 64bf266373d45d86153b3a09e9ea3bb36b5c072f..21887e88a0f2e1d0e674a4514bb538582d0b4a82 100644 (file)
--- a/doc/src/sgml/ref/alter_type.sgml
+++ b/doc/src/sgml/ref/alter_type.sgml
@@ -194,6 +194,14 @@ ALTER TYPE <replaceable class="parameter">name</replaceable> SET ( <replaceable
          requires superuser privilege.
         </para>
        </listitem>
+       <listitem>
+        <para>
+         <literal>SUBSCRIPT</literal> can be set to the name of a type-specific
+         subscripting handler function, or <literal>NONE</literal> to remove
+         the type's subscripting handler function.  Using this option
+         requires superuser privilege.
+        </para>
+       </listitem>
        <listitem>
         <para>
          <literal>STORAGE</literal><indexterm>

diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c
index 29fe52d2cefe01cccededb6998cb1c089b0a860c..7c0b2c3bf0223c790274dba417e85632d7202a81 100644 (file)
--- a/src/backend/commands/typecmds.c
+++ b/src/backend/commands/typecmds.c
@@ -94,6 +94,7 @@ typedef struct
    bool        updateTypmodin;
    bool        updateTypmodout;
    bool        updateAnalyze;
+   bool        updateSubscript;
    /* New values for relevant attributes */
    char        storage;
    Oid         receiveOid;
@@ -101,6 +102,7 @@ typedef struct
    Oid         typmodinOid;
    Oid         typmodoutOid;
    Oid         analyzeOid;
+   Oid         subscriptOid;
 } AlterTypeRecurseParams;
 
 /* Potentially set by pg_upgrade_support functions */
@@ -3885,6 +3887,18 @@ AlterType(AlterTypeStmt *stmt)
            /* Replacing an analyze function requires superuser. */
            requireSuper = true;
        }
+       else if (strcmp(defel->defname, "subscript") == 0)
+       {
+           if (defel->arg != NULL)
+               atparams.subscriptOid =
+                   findTypeSubscriptingFunction(defGetQualifiedName(defel),
+                                                typeOid);
+           else
+               atparams.subscriptOid = InvalidOid; /* NONE, remove function */
+           atparams.updateSubscript = true;
+           /* Replacing a subscript function requires superuser. */
+           requireSuper = true;
+       }
 
        /*
         * The rest of the options that CREATE accepts cannot be changed.
@@ -4042,6 +4056,11 @@ AlterTypeRecurse(Oid typeOid, bool isImplicitArray,
        replaces[Anum_pg_type_typanalyze - 1] = true;
        values[Anum_pg_type_typanalyze - 1] = ObjectIdGetDatum(atparams->analyzeOid);
    }
+   if (atparams->updateSubscript)
+   {
+       replaces[Anum_pg_type_typsubscript - 1] = true;
+       values[Anum_pg_type_typsubscript - 1] = ObjectIdGetDatum(atparams->subscriptOid);
+   }
 
    newtup = heap_modify_tuple(tup, RelationGetDescr(catalog),
                               values, nulls, replaces);
@@ -4098,6 +4117,7 @@ AlterTypeRecurse(Oid typeOid, bool isImplicitArray,
    atparams->updateReceive = false;    /* domains use F_DOMAIN_RECV */
    atparams->updateTypmodin = false;   /* domains don't have typmods */
    atparams->updateTypmodout = false;
+   atparams->updateSubscript = false;  /* domains don't have subscriptors */
 
    /* Skip the scan if nothing remains to be done */
    if (!(atparams->updateStorage ||

diff --git a/src/test/regress/expected/create_type.out b/src/test/regress/expected/create_type.out
index f85afcb31edf1cf0b2fd880718580859d1276eed..14394cc95cdd091d5777e82d7ff2cd59a3531c6e 100644 (file)
--- a/src/test/regress/expected/create_type.out
+++ b/src/test/regress/expected/create_type.out
@@ -260,38 +260,40 @@ ALTER TYPE myvarchar SET (
     receive = myvarcharrecv,
     typmod_in = varchartypmodin,
     typmod_out = varchartypmodout,
-    analyze = array_typanalyze  -- bogus, but it doesn't matter
+    -- these are bogus, but it's safe as long as we don't use the type:
+    analyze = ts_typanalyze,
+    subscript = raw_array_subscript_handler
 );
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = 'myvarchar';
-  typinput   |  typoutput   |  typreceive   |    typsend    |    typmodin     |    typmodout     |    typanalyze    | typstorage 
--------------+--------------+---------------+---------------+-----------------+------------------+------------------+------------
- myvarcharin | myvarcharout | myvarcharrecv | myvarcharsend | varchartypmodin | varchartypmodout | array_typanalyze | x
+  typinput   |  typoutput   |  typreceive   |    typsend    |    typmodin     |    typmodout     |  typanalyze   |        typsubscript         | typstorage 
+-------------+--------------+---------------+---------------+-----------------+------------------+---------------+-----------------------------+------------
+ myvarcharin | myvarcharout | myvarcharrecv | myvarcharsend | varchartypmodin | varchartypmodout | ts_typanalyze | raw_array_subscript_handler | x
 (1 row)
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = '_myvarchar';
- typinput | typoutput | typreceive |  typsend   |    typmodin     |    typmodout     |    typanalyze    | typstorage 
-----------+-----------+------------+------------+-----------------+------------------+------------------+------------
- array_in | array_out | array_recv | array_send | varchartypmodin | varchartypmodout | array_typanalyze | x
+ typinput | typoutput | typreceive |  typsend   |    typmodin     |    typmodout     |    typanalyze    |      typsubscript       | typstorage 
+----------+-----------+------------+------------+-----------------+------------------+------------------+-------------------------+------------
+ array_in | array_out | array_recv | array_send | varchartypmodin | varchartypmodout | array_typanalyze | array_subscript_handler | x
 (1 row)
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = 'myvarchardom';
- typinput  |  typoutput   | typreceive  |    typsend    | typmodin | typmodout |    typanalyze    | typstorage 
------------+--------------+-------------+---------------+----------+-----------+------------------+------------
- domain_in | myvarcharout | domain_recv | myvarcharsend | -        | -         | array_typanalyze | x
+ typinput  |  typoutput   | typreceive  |    typsend    | typmodin | typmodout |  typanalyze   | typsubscript | typstorage 
+-----------+--------------+-------------+---------------+----------+-----------+---------------+--------------+------------
+ domain_in | myvarcharout | domain_recv | myvarcharsend | -        | -         | ts_typanalyze | -            | x
 (1 row)
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = '_myvarchardom';
- typinput | typoutput | typreceive |  typsend   | typmodin | typmodout |    typanalyze    | typstorage 
-----------+-----------+------------+------------+----------+-----------+------------------+------------
- array_in | array_out | array_recv | array_send | -        | -         | array_typanalyze | x
+ typinput | typoutput | typreceive |  typsend   | typmodin | typmodout |    typanalyze    |      typsubscript       | typstorage 
+----------+-----------+------------+------------+----------+-----------+------------------+-------------------------+------------
+ array_in | array_out | array_recv | array_send | -        | -         | array_typanalyze | array_subscript_handler | x
 (1 row)
 
 -- ensure dependencies are straight

diff --git a/src/test/regress/sql/create_type.sql b/src/test/regress/sql/create_type.sql
index 584ece06701d32682f585dc49b714ab307057dfa..a32a9e67957e529384e09c7240cbd88b456414a7 100644 (file)
--- a/src/test/regress/sql/create_type.sql
+++ b/src/test/regress/sql/create_type.sql
@@ -207,23 +207,25 @@ ALTER TYPE myvarchar SET (
     receive = myvarcharrecv,
     typmod_in = varchartypmodin,
     typmod_out = varchartypmodout,
-    analyze = array_typanalyze  -- bogus, but it doesn't matter
+    -- these are bogus, but it's safe as long as we don't use the type:
+    analyze = ts_typanalyze,
+    subscript = raw_array_subscript_handler
 );
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = 'myvarchar';
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = '_myvarchar';
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = 'myvarchardom';
 
 SELECT typinput, typoutput, typreceive, typsend, typmodin, typmodout,
-       typanalyze, typstorage
+       typanalyze, typsubscript, typstorage
 FROM pg_type WHERE typname = '_myvarchardom';
 
 -- ensure dependencies are straight