Fix handling of files without newlines in brp-mangle-shebang

If the file we are trying to mangle a shebang in has
0 lines (as reported by `wc`) `read` command fails
to read the first line and the script fails silently.

Text files without newlines should not be executable as there
is no way for them to contain a shebang.

brp-mangle-shebangs

@@ -93,7 +93,14 @@ while IFS= read -r line; do
   fi
 
 
-  read shebang_line < "$f"
+  if ! read shebang_line < "$f"; then
+    echo >&2 "*** WARNING: Cannot read the first line from $f, removing executable bit"
+    ts=$(stat -c %y "$f")
+    chmod -x "$f"
+    touch -d "$ts" "$f"
+    continue
+  fi
+
   orig_shebang="${shebang_line#\#!}"
   if [ "$orig_shebang" = "$shebang_line" ]; then
     echo >&2 "*** WARNING: $f is executable but has no shebang, removing executable bit"

redhat-rpm-config.spec

@@ -6,7 +6,7 @@
 
 Summary: Red Hat specific rpm configuration files
 Name: redhat-rpm-config
-Version: 181
+Version: 182
 Release: 1%{?dist}
 # No version specified.
 License: GPL+
@@ -213,6 +213,9 @@ install -p -m 644 -t %{buildroot}%{_rpmluadir}/fedora/srpm forge.lua
 %{_rpmconfigdir}/macros.d/macros.kmp
 
 %changelog
+* Mon Mar 22 2021 Lumír Balhar <lbalhar@redhat.com> - 182-1
+- Fix handling of files without newlines in brp-mangle-shebang
+
 * Wed Mar 10 2021 Kalev Lember <klember@redhat.com> - 181-1
 - BRP Python Bytecompile: Avoid hardcoding /usr/bin prefix for python