libgit2: refactor max length values into constants

Signed-off-by: Paulo Gomes <paulo.gomes@weave.works>

pkg/git/libgit2/managed/const.go

@@ -0,0 +1,27 @@
+/*
+Copyright 2022 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package managed
+
+const (
+	// URLMaxLength represents the max length for the entire URL
+	// when cloning Git repositories via HTTP(S).
+	URLMaxLength = 2048
+
+	// PathMaxLength represents the max length for the path element
+	// when cloning Git repositories via SSH.
+	PathMaxLength = 4096
+)

pkg/git/libgit2/managed/http.go

@@ -171,8 +171,8 @@ func createClientRequest(targetUrl string, action git2go.SmartServiceAction, t *
 		}
 	}
 
-	if len(finalUrl) > 2048 {
-		return nil, nil, fmt.Errorf("URL exceeds the max length (2048)")
+	if len(finalUrl) > URLMaxLength {
+		return nil, nil, fmt.Errorf("URL exceeds the max length (%d)", URLMaxLength)
 	}
 
 	client := &http.Client{

pkg/git/libgit2/managed/ssh.go

@@ -130,8 +130,8 @@ func (t *sshSmartSubtransport) Action(urlString string, action git2go.SmartServi
 		return nil, err
 	}
 
-	if len(u.Path) > 4096 {
-		return nil, fmt.Errorf("path exceeds the max length (4096)")
+	if len(u.Path) > PathMaxLength {
+		return nil, fmt.Errorf("path exceeds the max length (%d)", PathMaxLength)
 	}
 
 	// decode URI's path