From: Ilya Zakharevich <ilya@math.berkeley.edu>
Date: Wed, 9 Dec 1998 10:39:31 +0000 (+0200)
Subject: Warn on unrecognized alpha escapes.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=c9f97d15d3a5d7fcbfc403087c4a4a450990ff7c;p=p5sagit%2Fp5-mst-13.2.git

Warn on unrecognized alpha escapes.

To: perl5-porters@perl.org (Mailing list Perl5)
Message-ID: <MLIST_199812090823.DAA17566@monk.mps.ohio-state.edu>

p4raw-id: //depot/cfgperl@2516
---

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 0b157c1..e0e9b12 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -57,6 +57,12 @@ no useful value.  See L<perlmod>.
 checksumming process loses information, and you can't go the other
 way.  See L<perlfunc/unpack>.
 
+=item /%s/: Unrecognized escape \\%c passed through
+
+(W) You used a backslash-character combination which is not recognized
+by Perl.  This combination appears in an interpolated variable or a 
+C<'>-delimited regular expression.
+
 =item %s (...) interpreted as function
 
 (W) You've run afoul of the rule that says that any list operator followed
@@ -2770,6 +2776,11 @@ an underbar into it.  You might also declare it as a subroutine.
 in your Perl script (or eval).  Perhaps you tried to run a compressed
 script, a binary program, or a directory as a Perl program.
 
+=item Unrecognized escape \\%c passed through
+
+(W) You used a backslash-character combination which is not recognized
+by Perl.
+
 =item Unrecognized signal name "%s"
 
 (F) You specified a signal name to the kill() function that was not recognized.
diff --git a/regcomp.c b/regcomp.c
index 2f39b27..82d2b8e 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -1878,6 +1878,8 @@ tryagain:
 		FAIL("trailing \\ in regexp");
 	    /* FALL THROUGH */
 	default:
+	    /* Do not generate `unrecognized' warnings here, we fall
+	       back into the quick-grab loop below */
 	    goto defchar;
 	}
 	break;
@@ -2008,6 +2010,11 @@ tryagain:
 			    FAIL("trailing \\ in regexp");
 			/* FALL THROUGH */
 		    default:
+			if (!SIZE_ONLY && ckWARN(WARN_UNSAFE) && isALPHA(*p))
+			    warner(WARN_UNSAFE, 
+				   "/%.127s/: Unrecognized escape \\%c passed through",
+				   PL_regprecomp,
+				   *p);
 			goto normal_default;
 		    }
 		    break;
diff --git a/toke.c b/toke.c
index b1bd0d7..b9fa540 100644
--- a/toke.c
+++ b/toke.c
@@ -1056,7 +1056,7 @@ scan_const(char *start)
 	    s++;
 
 	    /* some backslashes we leave behind */
-	    if (*s && strchr(leaveit, *s)) {
+	    if (*leaveit && *s && strchr(leaveit, *s)) {
 		*d++ = '\\';
 		*d++ = *s++;
 		continue;
@@ -1091,6 +1091,10 @@ scan_const(char *start)
 		/* FALL THROUGH */
 	    /* default action is to copy the quoted character */
 	    default:
+		if (ckWARN(WARN_UNSAFE) && isALPHA(*s))
+		    warner(WARN_UNSAFE, 
+			   "Unrecognized escape \\%c passed through",
+			   *s);
 		*d++ = *s++;
 		continue;