init.sh: work around OSF/1 5.1's mishandling of /dev/null

[gnulib.git] / tests / init.sh

diff --git a/tests/init.sh b/tests/init.sh
index e6f5f1c..5079010 100644 (file)
--- a/tests/init.sh
+++ b/tests/init.sh
@@ -74,7 +74,20 @@ Exit () { set +e; (exit $1); exit $1; }
 # the reason for skip/failure to console, rather than to the .log files.
 : ${stderr_fileno_=2}
 
-warn_ () { echo "$@" 1>&$stderr_fileno_; }
+# Note that correct expansion of "$*" depends on IFS starting with ' '.
+# Always write the full diagnostic to stderr.
+# When stderr_fileno_ is not 2, also emit the first line of the
+# diagnostic to that file descriptor.
+warn_ ()
+{
+  # If IFS does not start with ' ', set it and emit the warning in a subshell.
+  case $IFS in
+    ' '*) printf '%s\n' "$*" >&2
+          test $stderr_fileno_ = 2 \
+            || { printf '%s\n' "$*" | sed 1q >&$stderr_fileno_ ; } ;;
+    *) (IFS=' '; warn_ "$@");;
+  esac
+}
 fail_ () { warn_ "$ME_: failed test: $@"; Exit 1; }
 skip_ () { warn_ "$ME_: skipped test: $@"; Exit 77; }
 fatal_ () { warn_ "$ME_: hard error: $@"; Exit 99; }
@@ -208,16 +221,84 @@ export MALLOC_PERTURB_
 # a partition, or to undo any other global state changes.
 cleanup_ () { :; }
 
-if ( diff -u "$0" "$0" < /dev/null ) > /dev/null 2>&1; then
-  compare () { diff -u "$@"; }
-elif ( diff -c "$0" "$0" < /dev/null ) > /dev/null 2>&1; then
-  compare () { diff -c "$@"; }
+# Arrange not to let diff or cmp operate on /dev/null,
+# since on some systems (at least OSF/1 5.1), that doesn't work.
+# When there are not two arguments, or no argument is /dev/null, return 2.
+# When one argument is /dev/null and the other is not empty,
+# cat the nonempty file to stderr and return 1.
+# Otherwise, return 0.
+compare_dev_null_ ()
+{
+  test $# = 2 || return 2
+
+  if test "x$1" = x/dev/null; then
+    set dummy "$2" "$1"; shift
+  fi
+
+  test "x$2" = x/dev/null || return 2
+
+  test -s "$1" || return 0
+
+  cat - "$1" <<EOF >&2
+Unexpected contents of $1:
+EOF
+  return 1
+}
+
+if diff_out_=`( diff -u "$0" "$0" < /dev/null ) 2>/dev/null`; then
+  if test -z "$diff_out_"; then
+    compare_ () { diff -u "$@"; }
+  else
+    compare_ ()
+    {
+      if diff -u "$@" > diff.out; then
+        # No differences were found, but Solaris 'diff' produces output
+        # "No differences encountered". Hide this output.
+        rm -f diff.out
+        true
+      else
+        cat diff.out
+        rm -f diff.out
+        false
+      fi
+    }
+  fi
+elif diff_out_=`( diff -c "$0" "$0" < /dev/null ) 2>/dev/null`; then
+  if test -z "$diff_out_"; then
+    compare_ () { diff -c "$@"; }
+  else
+    compare_ ()
+    {
+      if diff -c "$@" > diff.out; then
+        # No differences were found, but AIX and HP-UX 'diff' produce output
+        # "No differences encountered" or "There are no differences between the
+        # files.". Hide this output.
+        rm -f diff.out
+        true
+      else
+        cat diff.out
+        rm -f diff.out
+        false
+      fi
+    }
+  fi
 elif ( cmp --version < /dev/null 2>&1 | grep GNU ) > /dev/null 2>&1; then
-  compare () { cmp -s "$@"; }
+  compare_ () { cmp -s "$@"; }
 else
-  compare () { cmp "$@"; }
+  compare_ () { cmp "$@"; }
 fi
 
+# Given compare_dev_null_'s preprocessing, defer to compare_ if 2 or more.
+# Otherwise, propagate $? to caller: any diffs have already been printed.
+compare ()
+{
+  compare_dev_null_ "$@"
+  case $? in
+    0|1) return $?;;
+    *) compare_ "$@";;
+  esac
+}
+
 # An arbitrary prefix to help distinguish test directories.
 testdir_prefix_ () { printf gt; }