patch 8.0.0645: no error for illegal back reference in NFA engine

Problem:    The new regexp engine does not give an error for using a back
            reference where it is not allowed. (Dominique Pelle)
Solution:   Check the back reference like the old engine. (closes #1774)

diff --git a/src/regexp.c b/src/regexp.c
index 74a73c44083ed6482ceaa0f3b1437877b24aa76f..7304bd349b21abcd283b51db0765388b19c61900 100644 (file)
--- a/src/regexp.c
+++ b/src/regexp.c
@@ -1294,6 +1294,34 @@ skip_regexp(
     return p;
 }
 
+/*
+ * Return TRUE if the back reference is legal. We must have seen the close
+ * brace.
+ * TODO: Should also check that we don't refer to something that is repeated
+ * (+*=): what instance of the repetition should we match?
+ */
+    static int
+seen_endbrace(int refnum)
+{
+    if (!had_endbrace[refnum])
+    {
+       char_u *p;
+
+       /* Trick: check if "@<=" or "@<!" follows, in which case
+        * the \1 can appear before the referenced match. */
+       for (p = regparse; *p != NUL; ++p)
+           if (p[0] == '@' && p[1] == '<' && (p[2] == '!' || p[2] == '='))
+               break;
+       if (*p == NUL)
+       {
+           EMSG(_("E65: Illegal back reference"));
+           rc_did_emsg = TRUE;
+           return FALSE;
+       }
+    }
+    return TRUE;
+}
+
 static regprog_T  *bt_regcomp(char_u *expr, int re_flags);
 static void bt_regfree(regprog_T *prog);
 
@@ -2099,24 +2127,8 @@ regatom(int *flagp)
                int                 refnum;
 
                refnum = c - Magic('0');
-               /*
-                * Check if the back reference is legal. We must have seen the
-                * close brace.
-                * TODO: Should also check that we don't refer to something
-                * that is repeated (+*=): what instance of the repetition
-                * should we match?
-                */
-               if (!had_endbrace[refnum])
-               {
-                   /* Trick: check if "@<=" or "@<!" follows, in which case
-                    * the \1 can appear before the referenced match. */
-                   for (p = regparse; *p != NUL; ++p)
-                       if (p[0] == '@' && p[1] == '<'
-                                             && (p[2] == '!' || p[2] == '='))
-                           break;
-                   if (*p == NUL)
-                       EMSG_RET_NULL(_("E65: Illegal back reference"));
-               }
+               if (!seen_endbrace(refnum))
+                   return NULL;
                ret = regnode(BACKREF + refnum);
            }
            break;

diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
index 5ba80f2fedbe58f84c2a803130b8bd3999427a9f..804d742ab3b63707a2f6e32c53fa8d6c21db578e 100644 (file)
--- a/src/regexp_nfa.c
+++ b/src/regexp_nfa.c
@@ -1446,8 +1446,14 @@ nfa_regatom(void)
        case Magic('7'):
        case Magic('8'):
        case Magic('9'):
-           EMIT(NFA_BACKREF1 + (no_Magic(c) - '1'));
-           nfa_has_backref = TRUE;
+           {
+               int refnum = no_Magic(c) - '1';
+
+               if (!seen_endbrace(refnum + 1))
+                   return FAIL;
+               EMIT(NFA_BACKREF1 + refnum);
+               nfa_has_backref = TRUE;
+           }
            break;
 
        case Magic('z'):

diff --git a/src/testdir/test_hlsearch.vim b/src/testdir/test_hlsearch.vim
index b934d38e1830d613e73615105b35ade585aeea5f..e9790bb9e54ef61c5e1ac269eeec669e1b764f83 100644 (file)
--- a/src/testdir/test_hlsearch.vim
+++ b/src/testdir/test_hlsearch.vim
@@ -38,11 +38,11 @@ func Test_hlsearch_hangs()
     return
   endif
 
-  " This pattern takes forever to match, it should timeout.
+  " This pattern takes a long time to match, it should timeout.
   help
   let start = reltime()
   set hlsearch nolazyredraw redrawtime=101
-  let @/ = '\%#=2\v(a|\1)*'
+  let @/ = '\%#=1a*.*X\@<=b*'
   redraw
   let elapsed = reltimefloat(reltime(start))
   call assert_true(elapsed > 0.1)

diff --git a/src/testdir/test_regexp_latin.vim b/src/testdir/test_regexp_latin.vim
index 247e5e65abefd35e7eaaf208393d3ecc52878bc5..a8fa64d2a7d854bfce4abdba3cad46a4c29b91a2 100644 (file)
--- a/src/testdir/test_regexp_latin.vim
+++ b/src/testdir/test_regexp_latin.vim
@@ -62,3 +62,13 @@ func Test_eow_with_optional()
     call assert_equal(expected, actual)
   endfor
 endfunc
+
+func Test_backref()
+  new
+  call setline(1, ['one', 'two', 'three', 'four', 'five'])
+  call assert_equal(3, search('\%#=1\(e\)\1'))
+  call assert_equal(3, search('\%#=2\(e\)\1'))
+  call assert_fails('call search("\\%#=1\\(e\\1\\)")', 'E65:')
+  call assert_fails('call search("\\%#=2\\(e\\1\\)")', 'E65:')
+  bwipe!
+endfunc

diff --git a/src/testdir/test_statusline.vim b/src/testdir/test_statusline.vim
index cf85bd58ac9a6aed840ac88cdc152002892d8875..351b119acd314b3dc9924bee88ff4bf867894ce3 100644 (file)
--- a/src/testdir/test_statusline.vim
+++ b/src/testdir/test_statusline.vim
@@ -223,7 +223,7 @@ func Test_statusline()
   set statusline=ab%(cd%q%)de
   call assert_match('^abde\s*$', s:get_statusline())
   copen
-  call assert_match('^abcd\[Quickfix List\1]de\s*$', s:get_statusline())
+  call assert_match('^abcd\[Quickfix List]de\s*$', s:get_statusline())
   cclose
 
   " %#: Set highlight group. The name must follow and then a # again.

diff --git a/src/version.c b/src/version.c
index 24bb8206b4e9fde9fc70cd939fd1612b49456d8d..2c3c45aed3014394b34aa22f029da7c73b70addc 100644 (file)
--- a/src/version.c
+++ b/src/version.c
@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    645,
 /**/
     644,
 /**/