ylwrap: preserve subdirectories in "#line" munging

If Automake is used in non-recursive mode and one of the inputs is a
yacc file, for example, "src/grammar.y", ylwrap will remove too many
directories from the output file when it adjusts the paths in it.
This results in #line directives referring to "grammar.y" instead of
"src/grammar.y".

This is a result of $input_rx simply taking all the directory
components of the absolute input path and removing them.

One solution is to store the path passed to ylwrap and replace
$input_rx with it.  This is what we do.

Suggestion and initial patch (without tests) by Nikolai Weibull:
<http://lists.gnu.org/archive/html/automake/2012-05/msg00013.html>
Final patch by Stefano Lattarini.

* lib/ylwrap ($input_sub_rx): New.
When munging the #line directives, substitute '$input_rx' with it,
instead of stripping it altogether.
Adjust comments.
* t/yacc-line.sh, t/lex-line: Adjust and extend.
* NEWS, THANKS: Update.

Copyright-paperwork-exempt: yes
Co-authored-by: Stefano Lattarini <stefano.lattarini@gmail.com>
Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

1 files changed, 20 insertions, 8 deletions

diff --git a/t/yacc-line.sh b/t/yacc-line.sh
index 090b72b57..d12215766 100755
--- a/t/yacc-line.sh
+++ b/t/yacc-line.sh
@@ -94,18 +94,30 @@ for vpath in : false; do
 
   # For debugging,
   ls -l . sub sub/dir
-  $FGREP '.y' $c_outputs
+  $EGREP 'line|\.y' $c_outputs
 
   # Adjusted "#line" should not contain reference to the builddir.
-  $EGREP '#.*line.*(build|\.\.).*\.y' $c_outputs && Exit 1
+  grep '#.*line.*build.*\.y' $c_outputs && Exit 1
+  # Adjusted "#line" should not contain reference to the absolute
+  # srcdir.
+  $EGREP '#.*line *"?/.*\.y' $c_outputs && Exit 1
   # Adjusted "#line" should not contain reference to the default
   # output file names, e.g., 'y.tab.c' and 'y.tab.h'.
-  $EGREP '#.*line.*y\.tab\.' $c_outputs && Exit 1
-  # Don't be excessively strict in grepping, to avoid spurious failures.
-  grep '#.*line.*zardoz\.y' zardoz.c
-  grep '#.*line.*quux\.y' bar-quux.c
-  grep '#.*line.*zardoz\.y' sub/foo-zardoz.c
-  grep '#.*line.*quux\.y' sub/dir/quux.c
+  grep '#.*line.*y\.tab\.' $c_outputs && Exit 1
+  # Look out for a silly regression.
+  grep "#.*\.y.*\.y" $c_outputs && Exit 1
+  if $vpath; then
+    grep '#.*line.*"\.\./zardoz\.y"' zardoz.c
+    grep '#.*line.*"\.\./dir/quux\.y"' bar-quux.c
+    grep '#.*line.*"\.\./\.\./sub/zardoz\.y"' sub/foo-zardoz.c
+    grep '#.*line.*"\.\./\.\./sub/dir/quux\.y"' sub/dir/quux.c
+  else
+    grep '#.*line.*"zardoz\.y"' zardoz.c
+    grep '#.*line.*"dir/quux\.y"' bar-quux.c
+    grep '#.*line.*"zardoz\.y"' sub/foo-zardoz.c
+    grep '#.*line.*"dir/quux\.y"' sub/dir/quux.c
+  fi
+
   cd $srcdir
 
 done