Re: [FYI] {maint} tests/README: update obsoleted advice

[Stefano Lattarini]

On Sunday 22 May 2011, Ralf Wildenhues wrote:
> * Stefano Lattarini wrote on Fri, May 20, 2011 at 10:21:09PM CEST:
> > * tests/README (Section "Writing test cases" subsection "Do"):
> > Do not suggest to use the `*-p.test' pattern for the names of
> > hand-written tests which use the `parallel-tests' Automake option.
> > Not only is this not respected by the existing tests, but it is
> > more likely to cause conflicts with auto-generated tests.
> > So, suggest to *avoid* using the `*-p.test' pattern in names
> > of hand-written tests instead.
> > (Section "Writing test cases" subsection "Do not"):  When
> > suggesting not to override Makefile variables using command
> > line arguments, do not use the badly outdated variables `U'
> > and 'ANSI2KNR' in the example; instead, use the more common
> > and typical `DESTDIR'.
> 
> Actually, this change has a slight technical error: when some variable
> is never initialized in the Makefile, -e is not necessary in order to
> override it.  DESTDIR is such a variable: we ensure that we do not ever
> initialize it.  And as such, it is quite portable to use
>   make DESTDIR=/foo/bar install
> 
> and in fact, quite widely used.
>
You're perfectly right.

> Can we use some other variable as example?  How about prefix?
>
Seems good.  I've prepared the attached patch (in your name, with me as
co-author in ChangeLog).  I'll wait for your ACK before pushing.

Sorry for the noise,
  Stefano

From aa6883fdcf1e7f21ea81fe4745c0018a9398d43f Mon Sep 17 00:00:00 2001
Message-Id: <address@hidden>
From: Ralf Wildenhues <address@hidden>
Date: Sun, 22 May 2011 19:02:27 +0200
Subject: [PATCH] tests/README: fix example about `make -e' usage

* tests/README (Section "Writing test cases" subsection "Do"): When
some variable is never initialized in the Makefile, `-e' is not
necessary in order to override it.  DESTDIR is such a variable: we
ensure that we do not ever initialize it.  And as such, it is quite
portable to use:
  $ make DESTDIR=/foo/bar install
and in fact, quite widely used.
So our example about when `make -e' is required, which references
the `DESTDIR' variable, is poorly chosen, if not downright wrong.
Rewrite it to use `prefix' as the overridden variable instead.
---
 ChangeLog    |   15 +++++++++++++++
 tests/README |    6 +++---
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3631129..583d3d4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2011-05-22  Ralf Wildenhues  <address@hidden>
+           Stefano Lattarini  <address@hidden>
+
+       tests/README: fix example about `make -e' usage
+       * tests/README (Section "Writing test cases" subsection "Do"): When
+       some variable is never initialized in the Makefile, `-e' is not
+       necessary in order to override it.  DESTDIR is such a variable: we
+       ensure that we do not ever initialize it.  And as such, it is quite
+       portable to use:
+         $ make DESTDIR=/foo/bar install
+       and in fact, quite widely used.
+       So our example about when `make -e' is required, which references
+       the `DESTDIR' variable, is poorly chosen, if not downright wrong.
+       Rewrite it to use `prefix' as the overridden variable instead.
+
 2011-05-20  Stefano Lattarini  <address@hidden>
 
        testsuite: avoid re-running few tests with 'parallel-tests' option
diff --git a/tests/README b/tests/README
index 9680a54..2b5b5af 100644
--- a/tests/README
+++ b/tests/README
@@ -181,11 +181,11 @@ Do not
   here.)
 
   Do not override Makefile variables using make arguments, as in e.g.:
-    $MAKE DESTDIR=/foo/bar install
+    $MAKE prefix=/opt install
   This is not portable for recursive targets (targets that call a
-  sub-make may not pass `DESTDIR=/foo/bar' along).  Use the following
+  sub-make may not pass `prefix=/opt' along).  Use the following
   instead:
-    DESTDIR=/foo/bar $MAKE -e install
+    prefix=/opt $MAKE -e install
 
   Do not send a test case without signing a copyright disclaimer.
   See http://sources.redhat.com/automake/contribute.html or
-- 
1.7.2.3