Fix check_name_length with non-ASCII characters

Previous version gave wrong result for arguments like:
SELECT check_name_length(repeat('josé', 15), '12345')::name

Makefile

@@ -44,6 +44,7 @@ NEW_FUNCS := calculate_time_partition_info.sql
 REPLACE_FUNCS_FILES := \
 	apply_constraints.sql \
 	check_default.sql \
+	check_name_length.sql \
 	drop_partition_id.sql \
 	drop_partition_time.sql \
 	dump_partitioned_table_definition.sql \

sql/functions/check_name_length.sql

@@ -8,8 +8,8 @@ CREATE FUNCTION @extschema@.check_name_length (
     SET search_path TO pg_catalog, pg_temp
     AS $$
 DECLARE
-    v_new_length    int;
     v_new_name      text;
+    v_suffix        text;
 BEGIN
 /*
  * Truncate the name of the given object if it is greater than the postgres default max (63 characters).
@@ -18,24 +18,25 @@ BEGIN
  * Retains SECURITY DEFINER since it is called by trigger functions and did not want to break installations prior to 4.0.0
  */
 
-IF p_table_partition IS TRUE AND (p_suffix IS NULL) THEN
+IF p_table_partition IS TRUE AND (NULLIF(p_suffix, '') IS NULL) THEN
     RAISE EXCEPTION 'Table partition name requires a suffix value';
 END IF;
 
-IF p_table_partition THEN  -- 61 characters to account for _p in partition name
-    IF char_length(p_object_name) + char_length(p_suffix) >= 61 THEN
-        v_new_length := 61 - char_length(p_suffix);
-        v_new_name := substring(p_object_name from 1 for v_new_length) || '_p' || p_suffix;
-    ELSE
-        v_new_name := p_object_name||'_p'||p_suffix;
-    END IF;
-ELSE
-    IF char_length(p_object_name) + char_length(COALESCE(p_suffix, '')) >= 63 THEN
-        v_new_length := 63 - char_length(COALESCE(p_suffix, ''));
-        v_new_name := substring(p_object_name from 1 for v_new_length) || COALESCE(p_suffix, '');
-    ELSE
-        v_new_name := p_object_name||COALESCE(p_suffix, '');
-    END IF;
+
+v_suffix := format('%s%s', CASE WHEN p_table_partition THEN '_p' END, p_suffix);
+-- Use optimistic behavior: in almost all cases `v_new_name` will be less than allowed maximum.
+-- Do "heavy" work only in rare cases.
+v_new_name := p_object_name || v_suffix;
+
+-- Postgres' relation name limit is in bytes, not characters; also it can be compiled with bigger allowed length.
+-- Use its internals to detect where to cut new object name.
+IF v_new_name::name != v_new_name THEN
+    -- Here we need to detect how many chars (not bytes) we need to get from the `p_object_name`.
+    -- Use suffix as prefix and get the rest of `p_object_name`.
+    v_new_name := (v_suffix || p_object_name)::name;
+    -- `substr` starts from 1, that is why we need to add 1 below.
+    -- Edge case: `v_suffix` is empty, length is 0, but need to start from 1.
+    v_new_name := substr(v_new_name, length(v_suffix) + 1) || v_suffix;
 END IF;
 
 RETURN v_new_name;

updates/pg_partman--4.7.3--5.0.0-beta.sql

@@ -805,6 +805,54 @@ END
 $$;
 
 
+CREATE OR REPLACE FUNCTION @extschema@.check_name_length (
+    p_object_name text
+    , p_suffix text DEFAULT NULL
+    , p_table_partition boolean DEFAULT FALSE
+)
+    RETURNS text
+    LANGUAGE plpgsql IMMUTABLE SECURITY DEFINER
+    SET search_path TO pg_catalog, pg_temp
+    AS $$
+DECLARE
+    v_new_name      text;
+    v_suffix        text;
+BEGIN
+/*
+ * Truncate the name of the given object if it is greater than the postgres default max (63 characters).
+ * Also appends given suffix and schema if given and truncates the name so that the entire suffix will fit.
+ * Returns original name (with suffix if given) if it doesn't require truncation
+ * Retains SECURITY DEFINER since it is called by trigger functions and did not want to break installations prior to 4.0.0
+ */
+
+IF p_table_partition IS TRUE AND (NULLIF(p_suffix, '') IS NULL) THEN
+    RAISE EXCEPTION 'Table partition name requires a suffix value';
+END IF;
+
+
+v_suffix := format('%s%s', CASE WHEN p_table_partition THEN '_p' END, p_suffix);
+-- Use optimistic behavior: in almost all cases `v_new_name` will be less than allowed maximum.
+-- Do "heavy" work only in rare cases.
+v_new_name := p_object_name || v_suffix;
+
+-- Postgres' relation name limit is in bytes, not characters; also it can be compiled with bigger allowed length.
+-- Use its internals to detect where to cut new object name.
+IF v_new_name::name != v_new_name THEN
+    -- Here we need to detect how many chars (not bytes) we need to get from the `p_object_name`.
+    -- Use suffix as prefix and get the rest of `p_object_name`.
+    v_new_name := (v_suffix || p_object_name)::name;
+    -- `substr` starts from 1, that is why we need to add 1 below.
+    -- Edge case: `v_suffix` is empty, length is 0, but need to start from 1.
+    v_new_name := substr(v_new_name, length(v_suffix) + 1) || v_suffix;
+END IF;
+
+RETURN v_new_name;
+
+END
+$$;
+
+
+
 CREATE FUNCTION @extschema@.check_subpart_sameconfig(p_parent_table text)
     RETURNS TABLE (
          sub_control text