Horton

Re: allow benign typedef redefinitions (C11)

Álvaro Herrera <alvherre@kurilemu.de>

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From: Álvaro Herrera <alvherre@kurilemu.de>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2025-09-19T19:58:53Z
Lists: pgsql-hackers

Attachments

I happened to realize that brin_tuple.h (a somewhat nasty header which
was only supposed to be used by BRIN itself and stuff like amcheck)
recently somehow snuck into tuplesort.h with some nefarious
consequences: that one has polluted execnodes.h, which means that header
now depends on struct definitions that appear in genam.h.  We should fix
this.  This patch is not the full solution, just a way to show the
problem; for a definitive solution, IMO the definitions of structs
IndexScanInstrumentation and SharedIndexScanInstrumentation should be
elsewhere so that execnodes.h doesn't have to include genam.h.

(gin_tuple.h is also there, but that one's much less of a problem.)

Oh, and replication/conflict.h including all of execnodes.h is kind of
ridiculous.  Looks like that's easily solved with something like this
though:

diff --git a/src/include/pgstat.h b/src/include/pgstat.h
index f402b17295c..7bcb4c68e18 100644
--- a/src/include/pgstat.h
+++ b/src/include/pgstat.h
@@ -11,6 +11,7 @@
 #ifndef PGSTAT_H
 #define PGSTAT_H

+#include "access/transam.h"
 #include "datatype/timestamp.h"
 #include "portability/instr_time.h"
 #include "postmaster/pgarch.h" /* for MAX_XFN_CHARS */
diff --git a/src/include/replication/conflict.h b/src/include/replication/conflict.h
index e516caa5c73..e71b3c8f3d3 100644
--- a/src/include/replication/conflict.h
+++ b/src/include/replication/conflict.h
@@ -9,9 +9,14 @@
 #ifndef CONFLICT_H
 #define CONFLICT_H

-#include "nodes/execnodes.h"
+#include "access/xlogdefs.h"
+#include "nodes/pg_list.h"
 #include "utils/timestamp.h"

+typedef struct EState EState;
+typedef struct ResultRelInfo ResultRelInfo;
+typedef struct TupleTableSlot TupleTableSlot;
+
 /*
  * Conflict types that could occur while applying remote changes.
  *


-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"La espina, desde que nace, ya pincha" (Proverbio africano)

Commits

  1. Move instrumentation-related structs to instrument_node.h

  2. Don't include access/htup_details.h in executor/tuptable.h

  3. Don't include execnodes.h in brin.h or gin.h

  4. Do a tiny bit of header file maintenance

  5. Don't include execnodes.h in replication/conflict.h

  6. Update some more forward declarations to use typedef

  7. Change fmgr.h typedefs to use original names

  8. Improve ExplainState type handling in header files

  9. Remove hbaPort type

  10. Remove workarounds against repeat typedefs

  11. Update various forward declarations to use typedef

  12. Allow redeclaration of typedef yyscan_t

  13. Improve pgbench definition of yyscan_t

  14. Delay extraction of TIDBitmap per page offsets

  15. Remove pgrminclude and associated scripts

  16. Allow to use HeapTupleData embedded in [Buffer]HeapTupleTableSlot.