Hi,
What about this wording:
The code that might throw ereport(ERROR) cannot contain any non local
control flow other than ereport(ERROR) e.g.: return, goto, break, continue.
In other words once PG_TRY() is executed, either PG_CATCH() or PG_FINALLY()
must be executed as well.
I used 'code that might throw ereport(ERROR)' for XXX since this is what's
used earlier in the comment.
On Tue, 12 Sept 2023 at 17:22, Tom Lane wrote:
> Serpent writes:
> > I'm talking about this part:
>
> > PG_TRY();
> > {
> > ... code that might throw ereport(ERROR) ...
> > }
>
> Ah. Your phrasing needs work for clarity then. Also, "return"
> is hardly the only way to break it; break, continue, or goto
> leading out of the PG_TRY are other possibilities. Maybe more
> like "The XXX code must exit normally (by control reaching
> the end) if it does not throw ereport(ERROR)." Not quite sure
> what to use for XXX.
>
> regards, tom lane
>
commit d077d0473378271d8cc4c0685b22ec61c9bce3f4
Author: Serpent7776
Date: Tue Sep 12 14:38:09 2023 +0200
Document that PG_TRY block cannot have a return statement
Document the fact that the block of code that follows `PG_TRY()` cannot
have any form of return statement, because `PG_TRY()` modifies global
state that is later restored in `PG_CATCH()` or `PG_FINALLY()`.
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 4a9562fdaa..1bcd146117 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -352,6 +352,11 @@ extern PGDLLIMPORT ErrorContextCallback *error_context_stack;
* You cannot use both PG_CATCH() and PG_FINALLY() in the same
* PG_TRY()/PG_END_TRY() block.
*
+ * The code that might throw ereport(ERROR) cannot contain any non local
+ * control flow other than ereport(ERROR) e.g.: return, goto, break, continue.
+ * In other words once PG_TRY() is executed, either PG_CATCH() or PG_FINALLY()
+ * must be executed as well.
+ *
* Note: while the system will correctly propagate any new ereport(ERROR)
* occurring in the recovery section, there is a small limit on the number
* of levels this will work for. It's best to keep the error recovery
