Merge branch 'pw/wildmatch-fixes'

The wildmatch library code unlearns exponential behaviour it
acquired some time ago since it was borrowed from rsync.

* pw/wildmatch-fixes:
  t3070: make chain lint tester happy
  wildmatch: hide internal return values
  wildmatch: avoid undefined behavior
  wildmatch: fix exponential behavior

Author: gitster

t/t3070-wildmatch.sh

@@ -431,4 +431,15 @@ match 1 1 1 1 'a' '[B-a]'
 match 0 1 0 1 'z' '[Z-y]'
 match 1 1 1 1 'Z' '[Z-y]'
 
+test_expect_success 'matching does not exhibit exponential behavior' '
+	{
+		test-tool wildmatch wildmatch \
+			aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaab \
+			"*a*a*a*a*a*a*a*a*a*a*a*a*a*a*a*a" &
+		pid=$!
+	} &&
+	sleep 2 &&
+	! kill $!
+'
+
 test_done

wildmatch.c

@@ -14,6 +14,10 @@
 
 typedef unsigned char uchar;
 
+/* Internal return values */
+#define WM_ABORT_ALL -1
+#define WM_ABORT_TO_STARSTAR -2
+
 /* What character marks an inverted character class? */
 #define NEGATE_CLASS	'!'
 #define NEGATE_CLASS2	'^'
@@ -83,12 +87,12 @@ static int dowild(const uchar *p, const uchar *text, unsigned int flags)
 			continue;
 		case '*':
 			if (*++p == '*') {
-				const uchar *prev_p = p - 2;
+				const uchar *prev_p = p;
 				while (*++p == '*') {}
 				if (!(flags & WM_PATHNAME))
 					/* without WM_PATHNAME, '*' == '**' */
 					match_slash = 1;
-				else if ((prev_p < pattern || *prev_p == '/') &&
+				else if ((prev_p - pattern < 2 || *(prev_p - 2) == '/') &&
 				    (*p == '\0' || *p == '/' ||
 				     (p[0] == '\\' && p[1] == '/'))) {
 					/*
@@ -114,7 +118,7 @@ static int dowild(const uchar *p, const uchar *text, unsigned int flags)
 				 * only if there are no more slash characters. */
 				if (!match_slash) {
 					if (strchr((char *)text, '/'))
-						return WM_NOMATCH;
+						return WM_ABORT_TO_STARSTAR;
 				}
 				return WM_MATCH;
 			} else if (!match_slash && *p == '/') {
@@ -125,7 +129,7 @@ static int dowild(const uchar *p, const uchar *text, unsigned int flags)
 				 */
 				const char *slash = strchr((char*)text, '/');
 				if (!slash)
-					return WM_NOMATCH;
+					return WM_ABORT_ALL;
 				text = (const uchar*)slash;
 				/* the slash is consumed by the top-level for loop */
 				break;
@@ -153,8 +157,12 @@ static int dowild(const uchar *p, const uchar *text, unsigned int flags)
 							break;
 						text++;
 					}
-					if (t_ch != p_ch)
-						return WM_NOMATCH;
+					if (t_ch != p_ch) {
+						if (match_slash)
+							return WM_ABORT_ALL;
+						else
+							return WM_ABORT_TO_STARSTAR;
+					}
 				}
 				if ((matched = dowild(p, text, flags)) != WM_NOMATCH) {
 					if (!match_slash || matched != WM_ABORT_TO_STARSTAR)
@@ -274,5 +282,6 @@ static int dowild(const uchar *p, const uchar *text, unsigned int flags)
 /* Match the "pattern" against the "text" string. */
 int wildmatch(const char *pattern, const char *text, unsigned int flags)
 {
-	return dowild((const uchar*)pattern, (const uchar*)text, flags);
+	int res = dowild((const uchar*)pattern, (const uchar*)text, flags);
+	return res == WM_MATCH ? WM_MATCH : WM_NOMATCH;
 }

wildmatch.h

@@ -6,8 +6,6 @@
 
 #define WM_NOMATCH 1
 #define WM_MATCH 0
-#define WM_ABORT_ALL -1
-#define WM_ABORT_TO_STARSTAR -2
 
 int wildmatch(const char *pattern, const char *text, unsigned int flags);
 #endif