Fix versionInRange for multi-interval OSV ranges (#18)

When an OSV range has multiple introduced/fixed intervals, a later
introduced event would overwrite inRange to false even when the version
was already matched by an earlier interval. Now introduced events can
only set inRange to true, never reset it to false.

Author: andrew

affected.go

@@ -28,7 +28,9 @@ func versionInRange(events []Event, version string) bool {
 	inRange := false
 	for _, e := range events {
 		if e.Introduced != "" {
-			inRange = e.Introduced == "0" || vers.Compare(version, e.Introduced) >= 0
+			if e.Introduced == "0" || vers.Compare(version, e.Introduced) >= 0 {
+				inRange = true
+			}
 		}
 		if e.Fixed != "" && inRange && vers.Compare(version, e.Fixed) >= 0 {
 			inRange = false

affected_test.go

@@ -113,3 +113,66 @@ func TestAffectedVersionRange(t *testing.T) {
 		})
 	}
 }
+
+func TestVersionInRangeMultiInterval(t *testing.T) {
+	events := []Event{
+		{Introduced: "0"},
+		{Fixed: "1.0.0"},
+		{Introduced: "2.0.0"},
+		{Fixed: "3.0.0"},
+	}
+
+	tests := []struct {
+		version string
+		want    bool
+	}{
+		{"0.5.0", true},
+		{"1.0.0", false},
+		{"1.5.0", false},
+		{"2.0.0", true},
+		{"2.5.0", true},
+		{"3.0.0", false},
+		{"4.0.0", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.version, func(t *testing.T) {
+			got := versionInRange(events, tt.version)
+			if got != tt.want {
+				t.Errorf("versionInRange(%q) = %v, want %v", tt.version, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestVersionInRangeMultiIntervalLastAffected(t *testing.T) {
+	events := []Event{
+		{Introduced: "1.0.0"},
+		{LastAffected: "1.9.0"},
+		{Introduced: "3.0.0"},
+		{LastAffected: "3.9.0"},
+	}
+
+	tests := []struct {
+		version string
+		want    bool
+	}{
+		{"0.5.0", false},
+		{"1.0.0", true},
+		{"1.5.0", true},
+		{"1.9.0", true},
+		{"2.0.0", false},
+		{"3.0.0", true},
+		{"3.9.0", true},
+		{"4.0.0", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.version, func(t *testing.T) {
+			got := versionInRange(events, tt.version)
+			if got != tt.want {
+				t.Errorf("versionInRange(%q) = %v, want %v", tt.version, got, tt.want)
+			}
+		})
+	}
+}