wildcard behavior, extend tests

Author: serprex

mysql/util.go

@@ -454,6 +454,10 @@ func ErrorEqual(err1, err2 error) bool {
 }
 
 func compareSubVersion(typ, a, b, aFull, bFull string) (int, error) {
+	if a == "" || b == "" {
+		return 0, nil
+	}
+
 	var aNum, bNum int
 	var err error
 
@@ -467,6 +471,9 @@ func compareSubVersion(typ, a, b, aFull, bFull string) (int, error) {
 	return cmp.Compare(aNum, bNum), nil
 }
 
+// Compares version triplet strings, ignoring anything past `-` in version.
+// A version string like 8.0 will compare as if third triplet were a wildcard.
+// A version string like 8 will compare as if second & third triplets were wildcards.
 func CompareServerVersions(a, b string) (int, error) {
 	aNumbers, _, _ := strings.Cut(a, "-")
 	bNumbers, _, _ := strings.Cut(b, "-")

mysql/util_test.go

@@ -15,13 +15,29 @@ func TestCompareServerVersions(t *testing.T) {
 	}{
 		{A: "1.2.3", B: "1.2.3", Expect: 0},
 		{A: "5.6-999", B: "8.0", Expect: -1},
+		{A: "5.6.3-999", B: "5.6", Expect: 0},
+		{A: "5.6.3-999", B: "5.5-tag", Expect: 1},
 		{A: "8.0.32-0ubuntu0.20.04.2", B: "8.0.28", Expect: 1},
+		{A: "a.b.c", B: "8.0", Expect: 2},
 	}
 
 	for _, test := range tests {
 		got, err := CompareServerVersions(test.A, test.B)
-		require.NoError(t, err)
-		require.Equal(t, test.Expect, got)
+		if test.Expect == 2 {
+			require.Error(t, err)
+		} else {
+			require.NoError(t, err)
+			require.Equal(t, test.Expect, got)
+		}
+
+		// test logic is commutative
+		got, err = CompareServerVersions(test.B, test.A)
+		if test.Expect == 2 {
+			require.Error(t, err)
+		} else {
+			require.NoError(t, err)
+			require.Equal(t, -test.Expect, got)
+		}
 	}
 }