Fix an assortment of improper usages of string functions

In a similar effort to f736e18 and 110d817, fixup various usages of
string functions where a more appropriate function is available and more
fit for purpose.

These changes include:

1. Use cstring_to_text_with_len() instead of cstring_to_text() when
   working with a StringInfoData and the length can easily be obtained.
2. Use appendStringInfoString() instead of appendStringInfo() when no
   formatting is required.
3. Use pstrdup(...) instead of psprintf("%s", ...)
4. Use pstrdup(...) instead of psprintf(...) (with no formatting)
5. Use appendPQExpBufferChar() instead of appendPQExpBufferStr() when the
   length of the string being appended is 1.
6. appendStringInfoChar() instead of appendStringInfo() when no formatting
   is required and string is 1 char long.
7. Use appendPQExpBufferStr(b, .) instead of appendPQExpBuffer(b, "%s", .)
8. Don't use pstrdup when it's fine to just point to the string constant.

I (David) did find other cases of postgres#8 but opted to use #4 instead as I
wasn't certain enough that applying postgres#8 was ok (e.g in hba.c)

Author: Ranier Vilela, David Rowley
Discussion: https://postgr.es/m/CAApHDvo2j2+RJBGhNtUz6BxabWWh2Jx16wMUMWKUjv70Ver1vg@mail.gmail.com

Author: david-rowley

contrib/hstore/hstore_io.c

@@ -1325,7 +1325,7 @@ hstore_to_json_loose(PG_FUNCTION_ARGS)
 	}
 	appendStringInfoChar(&dst, '}');
 
-	PG_RETURN_TEXT_P(cstring_to_text(dst.data));
+	PG_RETURN_TEXT_P(cstring_to_text_with_len(dst.data, dst.len));
 }
 
 PG_FUNCTION_INFO_V1(hstore_to_json);
@@ -1370,7 +1370,7 @@ hstore_to_json(PG_FUNCTION_ARGS)
 	}
 	appendStringInfoChar(&dst, '}');
 
-	PG_RETURN_TEXT_P(cstring_to_text(dst.data));
+	PG_RETURN_TEXT_P(cstring_to_text_with_len(dst.data, dst.len));
 }
 
 PG_FUNCTION_INFO_V1(hstore_to_jsonb);

contrib/sepgsql/schema.c

@@ -84,7 +84,7 @@ sepgsql_schema_post_create(Oid namespaceId)
 	 * check db_schema:{create}
 	 */
 	initStringInfo(&audit_name);
-	appendStringInfo(&audit_name, "%s", quote_identifier(nsp_name));
+	appendStringInfoString(&audit_name, quote_identifier(nsp_name));
 	sepgsql_avc_check_perms_label(ncontext,
 								  SEPG_CLASS_DB_SCHEMA,
 								  SEPG_DB_SCHEMA__CREATE,

src/backend/access/brin/brin_minmax_multi.c

@@ -3063,7 +3063,7 @@ brin_minmax_multi_summary_out(PG_FUNCTION_ARGS)
 
 		appendStringInfo(&str, "%s ... %s", a, b);
 
-		c = cstring_to_text(str.data);
+		c = cstring_to_text_with_len(str.data, str.len);
 
 		astate_values = accumArrayResult(astate_values,
 										 PointerGetDatum(c),
@@ -3095,15 +3095,9 @@ brin_minmax_multi_summary_out(PG_FUNCTION_ARGS)
 	{
 		Datum		a;
 		text	   *b;
-		StringInfoData str;
-
-		initStringInfo(&str);
 
 		a = FunctionCall1(&fmgrinfo, ranges_deserialized->values[idx++]);
-
-		appendStringInfoString(&str, DatumGetCString(a));
-
-		b = cstring_to_text(str.data);
+		b = cstring_to_text(DatumGetCString(a));
 
 		astate_values = accumArrayResult(astate_values,
 										 PointerGetDatum(b),

src/backend/access/rmgrdesc/xlogdesc.c

@@ -319,9 +319,9 @@ XLogRecGetBlockRefInfo(XLogReaderState *record, bool pretty,
 					*fpi_len += XLogRecGetBlock(record, block_id)->bimg_len;
 
 				if (XLogRecBlockImageApply(record, block_id))
-					appendStringInfo(buf, " FPW");
+					appendStringInfoString(buf, " FPW");
 				else
-					appendStringInfo(buf, " FPW for WAL verification");
+					appendStringInfoString(buf, " FPW for WAL verification");
 			}
 		}
 	}

src/backend/jit/llvm/llvmjit.c

@@ -514,7 +514,7 @@ llvm_function_reference(LLVMJitContext *context,
 	else if (basename != NULL)
 	{
 		/* internal function */
-		funcname = psprintf("%s", basename);
+		funcname = pstrdup(basename);
 	}
 	else
 	{

src/backend/libpq/hba.c

@@ -899,7 +899,7 @@ do { \
 				 errmsg("missing entry at end of line"), \
 				 errcontext("line %d of configuration file \"%s\"", \
 							line_num, IdentFileName))); \
-		*err_msg = psprintf("missing entry at end of line"); \
+		*err_msg = pstrdup("missing entry at end of line"); \
 		return NULL; \
 	} \
 } while (0)
@@ -912,7 +912,7 @@ do { \
 				 errmsg("multiple values in ident field"), \
 				 errcontext("line %d of configuration file \"%s\"", \
 							line_num, IdentFileName))); \
-		*err_msg = psprintf("multiple values in ident field"); \
+		*err_msg = pstrdup("multiple values in ident field"); \
 		return NULL; \
 	} \
 } while (0)

src/backend/postmaster/postmaster.c

@@ -4457,7 +4457,7 @@ BackendInitialize(Port *port)
 	appendStringInfo(&ps_data, "%s ", port->user_name);
 	if (!am_walsender)
 		appendStringInfo(&ps_data, "%s ", port->database_name);
-	appendStringInfo(&ps_data, "%s", port->remote_host);
+	appendStringInfoString(&ps_data, port->remote_host);
 	if (port->remote_port[0] != '\0')
 		appendStringInfo(&ps_data, "(%s)", port->remote_port);
 

src/backend/replication/logical/tablesync.c

@@ -769,7 +769,7 @@ fetch_remote_table_info(char *nspname, char *relname,
 		foreach(lc, MySubscription->publications)
 		{
 			if (foreach_current_index(lc) > 0)
-				appendStringInfo(&pub_names, ", ");
+				appendStringInfoString(&pub_names, ", ");
 			appendStringInfoString(&pub_names, quote_literal_cstr(strVal(lfirst(lc))));
 		}
 
@@ -1062,7 +1062,7 @@ copy_table(Relation rel)
 			appendStringInfoString(&cmd, quote_identifier(lrel.attnames[i]));
 		}
 
-		appendStringInfo(&cmd, ") TO STDOUT");
+		appendStringInfoString(&cmd, ") TO STDOUT");
 	}
 	else
 	{

src/backend/utils/adt/date.c

@@ -96,7 +96,7 @@ anytime_typmodout(bool istz, int32 typmod)
 	if (typmod >= 0)
 		return psprintf("(%d)%s", (int) typmod, tz);
 	else
-		return psprintf("%s", tz);
+		return pstrdup(tz);
 }
 
 

src/backend/utils/adt/misc.c

@@ -219,7 +219,7 @@ pg_tablespace_databases(PG_FUNCTION_ARGS)
 	}
 
 	if (tablespaceOid == DEFAULTTABLESPACE_OID)
-		location = psprintf("base");
+		location = "base";
 	else
 		location = psprintf("pg_tblspc/%u/%s", tablespaceOid,
 							TABLESPACE_VERSION_DIRECTORY);