Fix panic bug in handling multiple references in commit

The issue lay in determining the position of matches on a second run round
a commit message in FindAllIssueReferences.

Fix go-gitea#13483

Signed-off-by: Andrew Thornton <[email protected]>

Author: zeripath

modules/references/references.go

@@ -240,30 +240,67 @@ func FindAllIssueReferences(content string) []IssueReference {
 	// Need to convert fully qualified html references to local system to #/! short codes
 	contentBytes := []byte(content)
 	if re := getGiteaIssuePullPattern(); re != nil {
+		// We will iterate through the content, rewrite and simplify full references.
+		//
+		// We want to transform something like:
+		//
+		// 0         1         2         3         4         5         6
+		// 012345678901234567890123456789012345678901234567890123456789012345789
+		// this is a https://ourgitea.com/git/owner/repo/issues/123456789, foo
+		// https://ourgitea.com/git/owner/repo/pulls/123456789
+		//
+		// Into something like:
+		//
+		// this is a #123456789, foo
+		// !123456789
+
 		pos := 0
 		for {
+			// re looks for something like: (\s|^|\(|\[)https://ourgitea.com/git/(owner/repo)/(issues)/(123456789)(?:\s|$|\)|\]|[:;,.?!]\s|[:;,.?!]$)
 			match := re.FindSubmatchIndex(contentBytes[pos:])
 			if match == nil {
 				break
 			}
+			// match is a bunch of indices into the content from pos onwards so if our content is:
+
+			// To simplify things let's just add pos to all of the indices in match
+			for i := range match {
+				match[i] += pos
+			}
+
 			// match[0]-match[1] is whole string
 			// match[2]-match[3] is preamble
-			pos += match[3]
+
+			// move the position to the end of the preamble
+			pos = match[3]
+
 			// match[4]-match[5] is owner/repo
+			// now copy the owner/repo to end of the preamble
 			endPos := pos + match[5] - match[4]
 			copy(contentBytes[pos:endPos], contentBytes[match[4]:match[5]])
+
+			// move the current position to the end of the newly copied owner/repo
 			pos = endPos
+
+			// Now set the issue/pull marker:
+			//
 			// match[6]-match[7] == 'issues'
 			contentBytes[pos] = '#'
 			if string(contentBytes[match[6]:match[7]]) == "pulls" {
 				contentBytes[pos] = '!'
 			}
 			pos++
+
+			// Then add the issue/pull number
+			//
 			// match[8]-match[9] is the number
 			endPos = pos + match[9] - match[8]
 			copy(contentBytes[pos:endPos], contentBytes[match[8]:match[9]])
+
+			// Now copy what's left at the end of the string to the new end position
 			copy(contentBytes[endPos:], contentBytes[match[9]:])
 			// now we reset the length
+
 			// our new section has length endPos - match[3]
 			// our old section has length match[9] - match[3]
 			contentBytes = contentBytes[:len(contentBytes)-match[9]+endPos]

modules/references/references_test.go

@@ -106,6 +106,13 @@ func TestFindAllIssueReferences(t *testing.T) {
 				{202, "user4", "repo5", "202", true, XRefActionNone, nil, nil, ""},
 			},
 		},
+		{
+			"This http://gitea.com:3000/user4/repo5/pulls/202 yes. http://gitea.com:3000/user4/repo5/pulls/203 no",
+			[]testResult{
+				{202, "user4", "repo5", "202", true, XRefActionNone, nil, nil, ""},
+				{203, "user4", "repo5", "203", true, XRefActionNone, nil, nil, ""},
+			},
+		},
 		{
 			"This http://GiTeA.COM:3000/user4/repo6/pulls/205 yes.",
 			[]testResult{