Fix bug in $string.{contains,ends_with,replace}() (GH issue #405)

These functions use the common rfind() helper which contains the bug.

2 files changed, 4 insertions, 2 deletions

diff --git a/libbuild2/functions-string.cxx b/libbuild2/functions-string.cxx
index eccc6c7..58c17d7 100644
--- a/libbuild2/functions-string.cxx
+++ b/libbuild2/functions-string.cxx
@@ -38,14 +38,14 @@ namespace build2
     {
       n -= sn; // Don't consider characters out of range.
 
-      for (size_t p (n);; )
+      for (size_t p (n);; --p)
       {
         if ((ic
              ? icasecmp (ss, s.c_str () + p, sn)
              : s.compare (p, sn, ss)) == 0)
           return p;
 
-        if (--p == 0)
+        if (p == 0)
           break;
       }
     }
diff --git a/tests/function/string/testscript b/tests/function/string/testscript
index 8eb5760..57f30e2 100644
--- a/tests/function/string/testscript
+++ b/tests/function/string/testscript
@@ -47,6 +47,7 @@
   {
     $* <'print $string.contains(abcdabcd, da, once)' >'true'  : true
     $* <'print $string.contains(abcdabcd, bc, once)' >'false' : false
+    $* <'print $string.contains(abcdefgh, ab, once)' >'true'  : true-begin
   }
 }
 
@@ -76,6 +77,7 @@
   {
     $* <'print $string.ends_with(  abcd, cd)'   >'true'  : true
     $* <'print $string.ends_with(  abcd, bc)'   >'false' : false
+    $* <'print $string.ends_with(  abcd, xxxx)' >'false' : false-equal-size
     $* <'print $ends_with([string] abcd, abcd)' >'true'  : typed
   }