From 6d6c9b6c5dffec88e609f09cbee9c53ec2878c6a Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Wed, 28 Feb 2018 18:48:44 -0800
Subject: bugfix: missing actions in reset-struct.

* struct.c (reset_struct): Perform the post-init
actions are performed, not only the init actions.
Also, catch exceptions and call finalizers,
just like in a new structure instantiation.

* txr.1: Document the requirements for finalizers
being called by reset-struct, and clarify the issue of
possible duplicate finalization registration.
Add compat notes.
---
 struct.c | 16 ++++++++++++++++
 txr.1    | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/struct.c b/struct.c
index 6178340b..0e8b1080 100644
--- a/struct.c
+++ b/struct.c
@@ -726,14 +726,30 @@ val reset_struct(val strct)
   struct struct_inst *si = struct_handle(strct, self);
   struct struct_type *st = si->type;
   cnum i;
+  volatile val inited = nil;
+  int compat_190 = opt_compat && opt_compat <= 190;
 
   check_init_lazy_struct(strct, si);
 
+  uw_simple_catch_begin;
+
   for (i = 0; i < st->nslots; i++)
     si->slot[i] = nil;
 
   call_initfun_chain(st, strct);
 
+  if (!compat_190)
+    call_postinitfun_chain(st, strct);
+
+  inited = t;
+
+  uw_unwind {
+    if (!inited && !compat_190)
+      gc_call_finalizers(strct);
+  }
+
+  uw_catch_end;
+
   return strct;
 }
 
diff --git a/txr.1 b/txr.1
index 7264bb2e..a8a482b2 100644
--- a/txr.1
+++ b/txr.1
@@ -24773,7 +24773,8 @@ and no boa arguments.
 
 Note that finalizers registered against
 .meta struct-obj
-are not invoked, and remain registered.
+are not invoked prior to the reset operation, and remain registered.
+
 If the structure has state which is cleaned up by
 finalizers, it is advisable to invoke them using
 .code call-finalizers
@@ -24782,6 +24783,24 @@ prior to using
 or to take other measures to deal with the
 situation.
 
+If the structure specifies
+.code :fini
+handlers, then the reinitialization will cause
+these to registered, just like when a new object
+it constructed. Thus if
+.code call-finalizers
+is not used prior to
+.codn reset-struct ,
+this will result in the existence of duplicate registrations of the
+finalization functions.
+
+Finalizers registered against
+.meta struct-obj
+.B are
+invoked if an exception is thrown
+during the reinitialization, just like when a new
+structure is being constructed.
+
 .coNP Function @ replace-struct
 .synb
 .mets (replace-struct < target-obj << source-obj )
@@ -63207,6 +63226,16 @@ of these version values, the described behaviors are provided if
 is given an argument which is equal or lower. For instance
 .code "-C 103"
 selects the behaviors described below for version 105, but not those for 102.
+.IP 190
+Until \*(TX 190, the
+.code reset-struct
+function neglected to perform
+.code :postinit
+initializations, and didn't invoke finalization on the structure object
+if an exception was thrown during reinitialization. Thus, contrary
+to documented requirements, reinitialization of a structure didn't behave
+like fresh construction.  This behavior is replicated if compatibility
+with 190 or earlier is requested.
 .IP 188
 Until \*(TX 188,
 .codn equal -based
-- 
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