gps: wildcard ignore skip ineffectual ignores

internal/gps/pkgtree/pkgtree.go

@@ -1048,7 +1048,15 @@ func uniq(a []string) []string {
 func CreateIgnorePrefixTree(ig map[string]bool) *radix.Tree {
 	var xt *radix.Tree
 
-	for i := range ig {
+	// Create a sorted list of all the ignores to have a proper order in
+	// ignores parsing.
+	sortedIgnores := make([]string, len(ig))
+	for k := range ig {
+		sortedIgnores = append(sortedIgnores, k)
+	}
+	sort.Strings(sortedIgnores)
+
+	for _, i := range sortedIgnores {
 		// Skip global ignore.
 		if i == "*" {
 			continue
@@ -1060,6 +1068,12 @@ func CreateIgnorePrefixTree(ig map[string]bool) *radix.Tree {
 			if xt == nil {
 				xt = radix.New()
 			}
+			// Check if it is ineffectual.
+			_, _, ok := xt.LongestPrefix(i)
+			if ok {
+				// Skip ineffectual wildcard ignore.
+				continue
+			}
 			// Create the ignore prefix and insert in the radix tree.
 			xt.Insert(i[:len(i)-len(wcIgnoreSuffix)], true)
 		}

internal/gps/pkgtree/pkgtree_test.go

@@ -2086,6 +2086,17 @@ func TestCreateIgnorePrefixTree(t *testing.T) {
 			wantInTree:    []string{"gophers", "x/y/z"},
 			notWantInTree: []string{"*", "a/b/c"},
 		},
+		{
+			name: "ineffectual ignore with wildcard",
+			ignoreMap: map[string]bool{
+				"a/b*":    true,
+				"a/b/c*":  true,
+				"a/b/x/y": true,
+				"a/c*":    true,
+			},
+			wantInTree:    []string{"a/b", "a/c"},
+			notWantInTree: []string{"a/b/c", "a/b/x/y"},
+		},
 	}
 
 	for _, c := range cases {