On 12/22/2017 12:16 PM, Brandon Williams wrote:
On 12/22, Johannes Schindelin wrote:
[...]
That pattern is violated by OIDMAP_INIT, though. The first call to
oidmap_put() or oidmap_get() will succeed, but by mistake rather than by
design: The underlying hashmap is not initialized correctly, as the
cmpfn function pointer still points to NULL, but since there are no
entries to be compared, cmpfn will not be called. Things break down,
though, as soon as there is even one entry.
Rather than causing confusion, frustration and needless loss of time due
to pointless debugging, let's *rename* OIDMAP_INIT so that developers
who have gotten used to the pattern `struct xyz a = XYZ_INIT;` won't do
that with oidmaps.
-#define OIDMAP_INIT { { NULL } }
+/*
+ * This macro initializes the data structure only incompletely, just enough
+ * to call oidmap_get() on an empty map. Use oidmap_init() instead.
+ */
+#define OIDMAP_INIT_INCOMPLETELY { { NULL } }
Alternatively, could we define the macro to an expression
that would cause a compiler error? Then any new code written
would fail to compile. And we document the issue in a comment
above the macro so no one changes the macro to "fix" it.
(I suggest this as opposed to simply removing the macro
to prevent someone from re-adding it later, since it is the
standard pattern.)
Just a thought,
Jeff
