Add comment to extension/filefuncs.c discussing unref on value from assoc_lookup.

3 files changed, 12 insertions, 2 deletions

diff --git a/TODO.xgawk b/TODO.xgawk
index cf676c15..1917c73d 100644
--- a/TODO.xgawk
+++ b/TODO.xgawk
@@ -36,8 +36,6 @@ To do (not necessarily in this order):
 
 - The -f flag should not eliminate duplicates.
 
-- Add comment about using unref on value returned from assoc_lookup.
-
 - Enable default ".awk" search in io.c:find_source().  The simple change
   is to add this code inline in io.c:
       #ifndef DEFAULT_FILETYPE
diff --git a/extension/ChangeLog b/extension/ChangeLog
index df493227..a3526863 100644
--- a/extension/ChangeLog
+++ b/extension/ChangeLog
@@ -1,5 +1,10 @@
 2012-05-13         Andrew J. Schorr     <aschorr@telemetry-investments.com>
 
+	* filefuncs.c (array_set): Add a comment discussing the use of unref
+	on the value returned by assoc_lookup.
+
+2012-05-13         Andrew J. Schorr     <aschorr@telemetry-investments.com>
+
 	* xreadlink.[ch]: Remove unused files.
 
 2012-05-11         Arnold D. Robbins     <arnold@skeeve.com>
diff --git a/extension/filefuncs.c b/extension/filefuncs.c
index 9758ba8e..01f3fce2 100644
--- a/extension/filefuncs.c
+++ b/extension/filefuncs.c
@@ -220,6 +220,13 @@ array_set(NODE *array, const char *sub, NODE *value)
 	tmp = make_string(sub, strlen(sub));
 	aptr = assoc_lookup(array, tmp);
 	unref(tmp);
+	/* 
+	 * Note: since we initialized with assoc_clear, we know that aptr
+	 * has been initialized with Nnull_string.  Thus, the call to
+	 * unref(*aptr) is not strictly necessary.  However, I think it is
+	 * generally more correct to call unref to maintain the proper
+	 * reference count.
+	 */
 	unref(*aptr);
 	*aptr = value;
 }