Re: [PATCH] Fix exit status of signal handlers in shell scripts

[Bruno Haible]

Additionally, another proposed change prompted by Dmitry's patch.

The Autoconf manual
<http://www.gnu.org/software/autoconf/manual/html_node/Shell-Functions.html>
says:
  "the state of ‘$?’ is not reliable when entering a shell function. This has
   the effect that using a function as the first command in a trap handler can
   cause problems."

Here's a proposed fix (need to handle the same problem in bootstrap yourself):


2010-01-30  Bruno Haible  <address@hidden>

        Avoid unportable use of $? at the beginning of a shell function.
        * tests/init.sh (remove_tmp_): Don't deal with exit status here.
        (setup_): Do it directly in the trap handler here.

--- tests/init.sh.orig  Sun Jan 31 01:46:23 2010
+++ tests/init.sh       Sun Jan 31 01:46:09 2010
@@ -82,14 +82,12 @@
 # directory and exit with the incoming value of $?.
 remove_tmp_()
 {
-  __st=$?
   cleanup_
   # cd out of the directory we're about to remove
   cd "$initial_cwd_" || cd / || cd /tmp
   chmod -R u+rwx "$test_dir_"
   # If removal fails and exit status was to be 0, then change it to 1.
   rm -rf "$test_dir_" || { test $__st = 0 && __st=1; }
-  exit $__st
 }
 
 # Use this function to prepend to PATH an absolute name for each
@@ -127,7 +125,7 @@
 
   # This pair of trap statements ensures that the temporary directory,
   # $test_dir_, is removed upon exit as well as upon catchable signal.
-  trap remove_tmp_ 0
+  trap 'status=$?; remove_tmp_; exit $status' 0
   trap 'Exit $?' 1 2 13 15
 }