Document intentional violations of header inclusion policy.

tglsfdc · tglsfdc · commit d6b059ec740a · 2017-03-08T17:01:13.000-05:00
Although there are good reasons for our policy of including postgres.h as the first #include in every .c file, never from .h files, there are two places where it seems expedient to violate the policy because the alternative is to modify externally-supplied .c files. (In the case of the regexp library, the idea that it's externally-supplied is kind of at odds with reality, but I haven't entirely given up hope that it will become a standalone project some day.) Add some comments to make it explicit that this is a policy violation and provide the reasoning. In passing, move #include "miscadmin.h" out of regcomp.c and into regcustom.h, which is where it should be if we're taking this reasoning seriously at all. Discussion: https://postgr.es/m/CAEepm=2zCoeq3QxVwhS5DFeUh=yU6z81pbWMgfOB8OzyiBwxzw@mail.gmail.com Discussion: https://postgr.es/m/11634.1488932128@sss.pgh.pa.us
diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c
@@ -34,8 +34,6 @@
 
 #include "regex/regguts.h"
 
-#include "miscadmin.h"			/* needed by rcancelrequested/rstacktoodeep */
-
 /*
  * forward declarations, up here so forward datatypes etc. are defined early
  */
diff --git a/src/include/regex/regcustom.h b/src/include/regex/regcustom.h
@@ -29,6 +29,13 @@
  */
 
 /* headers if any */
+
+/*
+ * It's against Postgres coding conventions to include postgres.h in a
+ * header file, but we allow the violation here because the regexp library
+ * files specifically intend this file to supply application-dependent
+ * headers, and are careful to include this file before anything else.
+ */
 #include "postgres.h"
 
 #include <ctype.h>
@@ -47,6 +54,8 @@
 
 #include "mb/pg_wchar.h"
 
+#include "miscadmin.h"			/* needed by rcancelrequested/rstacktoodeep */
+
 
 /* overrides for regguts.h definitions, if any */
 #define FUNCPTR(name, args) (*name) args
diff --git a/src/include/snowball/header.h b/src/include/snowball/header.h
@@ -22,6 +22,11 @@
 #ifndef SNOWBALL_HEADR_H
 #define SNOWBALL_HEADR_H
 
+/*
+ * It's against Postgres coding conventions to include postgres.h in a
+ * header file, but we allow the violation here because the alternative is
+ * to modify the machine-generated .c files provided by the Snowball project.
+ */
 #include "postgres.h"
 
 /* Some platforms define MAXINT and/or MININT, causing conflicts */
