From 16a5ff8e22aa0302fe73fc447eb26e018fb02e1a Mon Sep 17 00:00:00 2001
From: Clark Boylan <clark.boylan@gmail.com>
Date: Thu, 25 Aug 2022 16:18:45 -0700
Subject: [PATCH] Fix IsVendor() regex generation

The regex generation introduced by
https://github.com/go-enry/go-enry/commit/20726a1de3cdff1d64bf0a6e5f6e2475a2c96913
had a subtle but important bug in it. In particular the ^ and ^|/
prefixes were only applied to the first regex in the OR'd groupings and
not every regex in the grouping.

We fix this by wrapping each of those OR'd groups in a new non capturing
group to ensure the prefix applies to every entry in the OR'd listing.

Additionally we add three new quick tests of IsVendor to guard against
this regression in the future.

This fixes https://github.com/go-enry/go-enry/issues/135
---
 utils.go      | 8 ++++----
 utils_test.go | 3 +++
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/utils.go b/utils.go
index c3ff632..f48f29a 100644
--- a/utils.go
+++ b/utils.go
@@ -213,23 +213,23 @@ func init() {
 	sb := &strings.Builder{}
 
 	// Start with group 1 - those that started with `^`
-	sb.WriteString("(?:^(?:")
+	sb.WriteString("(?:^(?:(?:")
 	sb.WriteString(caretStrings[0])
 	for _, matcher := range caretStrings[1:] {
 		sb.WriteString(")|(?:")
 		sb.WriteString(matcher)
 	}
-	sb.WriteString("))")
+	sb.WriteString(")))")
 	sb.WriteString("|")
 
 	// Now add group 2 - those that started with `(^|/)`
-	sb.WriteString("(?:(?:^|/)(?:")
+	sb.WriteString("(?:(?:^|/)(?:(?:")
 	sb.WriteString(caretSegmentStrings[0])
 	for _, matcher := range caretSegmentStrings[1:] {
 		sb.WriteString(")|(?:")
 		sb.WriteString(matcher)
 	}
-	sb.WriteString("))")
+	sb.WriteString(")))")
 	sb.WriteString("|")
 
 	// Finally add the rest
diff --git a/utils_test.go b/utils_test.go
index 56fc4c9..fd031ab 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -17,6 +17,7 @@ func TestIsVendor(t *testing.T) {
 		expected bool
 	}{
 		{"cache/", true},
+		{"something_cache/", false},
 		{"random/cache/", true},
 		{"cache", false},
 		{"dependencies/", true},
@@ -27,6 +28,7 @@ func TestIsVendor(t *testing.T) {
 		{"random/dist/", true},
 		{"random/dist", false},
 		{"deps/", true},
+		{"foodeps/", false},
 		{"configure", true},
 		{"a/configure", true},
 		{"config.guess", true},
@@ -43,6 +45,7 @@ func TestIsVendor(t *testing.T) {
 		{"foo/bar/MochiKit.js", true},
 		{"foo/bar/dojo.js", true},
 		{"foo/env/whatever", true},
+		{"some/python/venv/", false},
 		{"foo/.imageset/bar", true},
 		{"Vagrantfile", true},
 	}