[PATCH v2] Properly handle funny file names for headers in config.status.

[Benoit Sigoure]

        The test suite did not cover this bug because the code was not
        quoting properly the arguments of `rm -f' (which "fails" silently)
        as well as the arguments of `diff' (whose output was redirected to
        /dev/null so we couldn't see its error message).
        * lib/autoconf/status.m4 (_AC_OUTPUT_HEADER): Properly quote the
        file names passed to `rm' and `diff'.
        * tests/torture.at (AC_CONFIG_FILES, HEADERS, LINKS and COMMANDS):
        Add a regression test.

Signed-off-by: Benoit Sigoure <address@hidden>
---
I noticed that my previous attempt to fix this bug introduced a minor problem
in that the comment "/* file $file Generated from $file.in by configure.  */"
was also using the escaped version of "$file", which is not very nice.  I
adjusted the testsuite to cover this too.

 lib/autoconf/status.m4 |   19 +++++++++++--------
 tests/torture.at       |    9 +++++++++
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/lib/autoconf/status.m4 b/lib/autoconf/status.m4
index 21abe54..03733b4 100644
--- a/lib/autoconf/status.m4
+++ b/lib/autoconf/status.m4
@@ -624,6 +624,13 @@ esac
 _ACEOF
 ])dnl
 
+# Neutralize special characters interpreted by sed in replacement strings.
+case $configure_input in #(
+  *'&'*) ac_sed_conf_input=`AS_ECHO(["$configure_input"]) |
+                             sed 's/\\\\/\\\\\\\\/g;s/&/\\\\\\&/g'`;;
+  *) ac_sed_conf_input=$configure_input
+esac
+
 # Neutralize VPATH when `$srcdir' = `.'.
 # Shell code in configure.ac might set extrasub.
 # FIXME: do we really want to maintain this feature?
@@ -635,7 +642,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 :t
 [/@[a-zA-Z_][a-zA-Z_0-9]*@/!b]
 dnl configure_input is a somewhat special, so we don't call AC_SUBST_TRACE.
-s&@configure_input@&$configure_input&;t t
+s&@configure_input@&$ac_sed_conf_input&;t t
 dnl During the transition period, this is a special case:
 s&@top_builddir@&$ac_top_builddir_sub&;t t[]AC_SUBST_TRACE([top_builddir])
 dnl For this substitution see the witness macro _AC_HAVE_TOP_BUILD_PREFIX 
above.
@@ -861,10 +868,10 @@ m4_define([_AC_OUTPUT_HEADER],
       && eval '$AWK -f "$tmp/defines.awk"' "$ac_file_inputs"
     } >"$tmp/config.h" \
       || AC_MSG_ERROR([could not create $ac_file])
-    if diff $ac_file "$tmp/config.h" >/dev/null 2>&1; then
+    if diff "$ac_file" "$tmp/config.h" >/dev/null 2>&1; then
       AC_MSG_NOTICE([$ac_file is unchanged])
     else
-      rm -f $ac_file
+      rm -f "$ac_file"
       mv "$tmp/config.h" "$ac_file" \
        || AC_MSG_ERROR([could not create $ac_file])
     fi
@@ -876,7 +883,7 @@ m4_define([_AC_OUTPUT_HEADER],
 dnl If running for Automake, be ready to perform additional
 dnl commands to set up the timestamp files.
 m4_ifdef([_AC_AM_CONFIG_HEADER_HOOK],
-        [_AC_AM_CONFIG_HEADER_HOOK([$ac_file])
+        [_AC_AM_CONFIG_HEADER_HOOK(["$ac_file"])
 ])dnl
 ])# _AC_OUTPUT_HEADER
 
@@ -1655,10 +1662,6 @@ do
       configure_input="$ac_file.  $configure_input"
       AC_MSG_NOTICE([creating $ac_file])
     fi
-    case $configure_input in #(
-      *'&'*) configure_input=`AS_ECHO(["$configure_input"]) |
-                               sed 's/\\\\/\\\\\\\\/g;s/&/\\\\\\&/g'`;;
-    esac
 
     case $ac_tag in
     *:-:* | *:-) cat >"$tmp/stdin" \
diff --git a/tests/torture.at b/tests/torture.at
index 6a7b962..c1ec29a 100644
--- a/tests/torture.at
+++ b/tests/torture.at
@@ -274,6 +274,15 @@ AT_CHECK([grep OK "$file"], [], [OK
 ])
 AT_CHECK([./config.status "--header=$file:$file.in"],
         [0], [ignore])
+# Run the same test a 2nd time to see that config.status does not recreate
+# the header (regression test)
+AT_CHECK([./config.status "--header=$file:$file.in"],
+        [0], [config.status: creating file with  funny \ ' \' $ & #!*? name
+config.status: file with  funny \ ' \' $ & #!*? name is unchanged
+])
+AT_CHECK([grep ' & ' "$file"], [],
+[/* file with  funny \ ' \' $ & #!*? name.  Generated from file with  funny \ 
' \' $ & #!*? name.in by configure.  */
+])
 AT_CHECK([grep OK "$file"], [], [OK
 ])
 AT_CLEANUP
-- 
1.5.3.7.997.g4ff2-dirty