[libvirt PATCH 2/4] docs: coding-style: Rewrite section on shortening comparisons

[Ján Tomko]

On a Friday in 2022, Tim Wiederhake wrote:
>The code style showed `bool hasFoos; if (hasFoos == true)` as a
>good example in one place, only to warn against comparisons with
>`true` a couple of paragraphs further down.
>
>Merge this advice on comparing with `true` into the "Conditional
>expressions" section and split the example up for readability.
>
>Signed-off-by: Tim Wiederhake <twiederh at redhat.com>
>---
> docs/coding-style.rst | 60 +++++++++++++++++++++++++++----------------
> 1 file changed, 38 insertions(+), 22 deletions(-)
>
>diff --git a/docs/coding-style.rst b/docs/coding-style.rst
>index dca9de1915..3dedb032f4 100644
>--- a/docs/coding-style.rst
>+++ b/docs/coding-style.rst
>@@ -427,25 +427,47 @@ Conditional expressions
> -----------------------
>
> For readability reasons new code should avoid shortening
>-comparisons to 0 for numeric types. Boolean and pointer
>-comparisons may be shortened. All long forms are okay:
>+comparisons to 0 for numeric types:
>
> ::
>
>-  virFoo *foos = NULL;
>   size nfoos = 0;
>-  bool hasFoos = false;
>
>   GOOD:
>-    if (!foos)
>-    if (!hasFoos)
>+    if (nfoos != 0)
>     if (nfoos == 0)
>-    if (foos == NULL)
>-    if (hasFoos == true)
>
>   BAD:
>-    if (!nfoos)
>     if (nfoos)
>+    if (!nfoos)
>+
>+Prefer the shortened version for boolean values. Boolean values
>+should never be compared against the literal ``true``, as a
>+logical non-false value need not be ``1``.
>+
>+::
>+
>+  bool hasFoos = false;
>+
>+  GOOD:
>+    if (hasFoos)
>+    if (!hasFoos)
>+
>+  BAD:
>+    if (hasFoos == true)
>+    if (hasFoos != false)
>+    if (hasFoos == false)
>+    if (hasFoos != true)

I think people would get it even if all four options weren't listed :)

>+
>+Pointer comparisons may be shortened. All long forms are okay.
>+

Either way:

Reviewed-by: Ján Tomko <jtomko at redhat.com>

Jano
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