From c04b6b0a20c17ffbfa799178b2cb1457e4bf510b Mon Sep 17 00:00:00 2001
From: Attila Kovacs <attipaci@gmail.com>
Date: Sun, 17 Nov 2024 16:59:11 +0100
Subject: [PATCH] make_object() to remain safe for objects compiled with older
 version of the `object` structure.

---
 include/novas.h |  2 +-
 src/novas.c     | 15 ++++++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/novas.h b/include/novas.h
index 8b238f1c..4a85b5d1 100644
--- a/include/novas.h
+++ b/include/novas.h
@@ -803,7 +803,7 @@ typedef struct {
   long number;                    ///< enum novas_planet, or minor planet ID (e.g. NAIF), or star catalog ID.
   char name[SIZE_OF_OBJ_NAME];    ///< name of the object (0-terminated)
   cat_entry star;                 ///< basic astrometric data for NOVAS_CATALOG_OBJECT type.
-  novas_orbital_elements orbit;   ///< orbital data for NOVAS_ORBITAL_OBJECT TYPE. @since 1.2
+  novas_orbital_elements orbit;   ///< orbital data for NOVAS_ORBITAL_OBJECT type. @since 1.2
 } object;
 
 /**
diff --git a/src/novas.c b/src/novas.c
index 008d876f..587e36b8 100644
--- a/src/novas.c
+++ b/src/novas.c
@@ -21,6 +21,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <stdarg.h>   // stdarg.h before stdio.h (for older gcc...)
+#include <stddef.h>
 
 #if !COMPAT
 #  include <stdio.h>
@@ -6715,6 +6716,13 @@ void novas_case_sensitive(int value) {
  * compatibility with NOVAS C) source names are converted to upper-case internally. You can
  * however enable case-sensitive processing by calling novas_case_sensitive() before.
  *
+ * NOTES:
+ * <ol>
+ * <li>This call does not initialize the `orbit` field (added in v1.2) with zeroes to remain ABI
+ * compatible with versions &lt;1.2, and to avoid the possiblity of segfaulting if used to
+ * initialize a legacy `object` variable.</li>
+ * </ol>
+ *
  * @param type          The type of object. NOVAS_PLANET (0), NOVAS_EPHEM_OBJECT (1) or
  *                      NOVAS_CATALOG_OBJECT (2), or NOVAS_ORBITAL_OBJECT (3).
  * @param number        The novas ID number (for solar-system bodies only, otherwise ignored)
@@ -6746,7 +6754,8 @@ short make_object(enum novas_object_type type, long number, const char *name, co
   if(!source)
     return novas_error(-1, EINVAL, fn, "NULL input source");
 
-  memset(source, 0, sizeof(*source));
+  // FIXME for version v2.x initialize the entire structure again...
+  memset(source, 0, offsetof(object, orbit));
 
   // Set the object type.
   if(type < 0 || type >= NOVAS_OBJECT_TYPES)
@@ -6759,6 +6768,10 @@ short make_object(enum novas_object_type type, long number, const char *name, co
     if(number < 0 || number >= NOVAS_PLANETS)
       return novas_error(2, EINVAL, fn, "planet number %ld is out of bounds [0:%d]", number, NOVAS_PLANETS - 1);
 
+  // FIXME will not need special case in v2.x
+  if(type == NOVAS_ORBITAL_OBJECT)
+    memset(&source->orbit, 0, sizeof(source->orbit));
+
   source->number = number;
 
   if(name) {