Subject: Re: [PATCH 01/19] check_bindir: convert test -a/-o to && and ||

From: Junio C Hamano <[email-masked]>
Date: Tue, 20 May 2014 11:12:02 -0700

Elia Pinto <[email-masked]> writes:

> The interaction with unary operators and operator precedence
> for && and || are better known than -a and -o, and for that
> reason we prefer them. Replace all existing instances
> of -a and -o to save readers from the burden of thinking
> about such things.
>
> Signed-off-by: Elia Pinto <[email-masked]>
> ---

Thanks.

As I already said, I think "better known" is much less of an issue
than that "-a/-o" is "more error prone", and that is the reason why
we may want to do this rewrite.

I do not know offhand how busy the tree would be when we can apply
these patches post-release without them getting rebased, but the
zero-th step before this series may want to be a patch like this.

 Documentation/CodingGuidelines | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index ef67b53..7864c5b 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -106,6 +106,19 @@ For shell scripts specifically (not exhaustive):
    interface translatable. See "Marking strings for translation" in
    po/README.
 
+ - We do not write our "test" command with "-a" and "-o" and use "&&"
+   or "||" to concatenate multiple "test" commands instead, because
+   the use of "-a/-o" is often error-prone.  E.g.
+
+     test -n "$x" -a "$a" = "$b"
+
+   is buggy and breaks when $x is "=", but
+
+     test -n "$x" && test "$a" = "$b"
+
+   does not have such a problem.
+
+
 For C programs:
 
  - We use tabs to indent, and interpret tabs as taking up to