docs: hacking: Discourage use of the ternary operator and ban it's abuse

Forbid breaking lines inside the two branches of the ternary operator
and nesting them. Using it in these instances does not help readability.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
ACKed-by: Eric Blake <eblake@redhat.com>

diff --git a/docs/hacking.html.in b/docs/hacking.html.in
index 1f82c668e52807b32ed20e7a5c4a4f4af37f77ee..859e33a874f2f2d84d9374ecf88370ff4c2a62e0 100644 (file)
--- a/docs/hacking.html.in
+++ b/docs/hacking.html.in
@@ -847,6 +847,17 @@ BAD:
     if (!nfoos)
     if (nfoos)
 </pre>
+      <p>New code should avoid the ternary operator as much as possible.
+        Specifically it must never span more than one line or nest:
+      </p>
+<pre>
+BAD:
+    char *foo = baz ?
+                virDoSomethingReallyComplex(driver, vm, something, baz->foo) :
+                NULL;
+
+    char *foo = bar ? bar->baz ? bar->baz->foo : "nobaz" : "nobar";
+</pre>
 
     <h2><a id="preprocessor">Preprocessor</a></h2>