Fix #2937 - helm always appends /index.yaml at the end of URL (#2988)

* Closes #2937
Added required dependency to run make test in developer's guide

* Fixed base URL appending when chart address is not absolute

* Removed requirement from developers.md

* Fixed unnecessary line breaks

* Added tests for query string repo

* Returning URL along with error

pkg/downloader/chart_downloader.go

@@ -217,7 +217,12 @@ func (c *ChartDownloader) ResolveChartVersion(ref, version string) (*url.URL, ge
 
 	// If the URL is relative (no scheme), prepend the chart repo's base URL
 	if !u.IsAbs() {
-		u, err = url.Parse(rc.URL + "/" + u.Path)
+		path := u.Path
+		u, err = url.Parse(rc.URL)
+		if err != nil {
+			return u, r.Client, err
+		}
+		u.Path = u.Path + path
 		return u, r.Client, err
 	}
 

pkg/downloader/chart_downloader_test.go

@@ -43,6 +43,7 @@ func TestResolveChartRef(t *testing.T) {
 		{name: "reference, testing repo", ref: "testing/alpine", expect: "http://example.com/alpine-1.2.3.tgz"},
 		{name: "reference, version, testing repo", ref: "testing/alpine", version: "0.2.0", expect: "http://example.com/alpine-0.2.0.tgz"},
 		{name: "reference, version, malformed repo", ref: "malformed/alpine", version: "1.2.3", expect: "http://dl.example.com/alpine-1.2.3.tgz"},
+		{name: "reference, querystring repo", ref: "testing-querystring/alpine", expect: "http://example.com/alpine-1.2.3.tgz?key=value"},
 		{name: "full URL, HTTPS, irrelevant version", ref: "https://example.com/foo-1.2.3.tgz", version: "0.1.0", expect: "https://example.com/foo-1.2.3.tgz", fail: true},
 		{name: "full URL, file", ref: "file:///foo-1.2.3.tgz", fail: true},
 		{name: "invalid", ref: "invalid-1.2.3", fail: true},

pkg/downloader/testdata/helmhome/repository/cache/testing-querystring-index.yaml

@@ -0,0 +1,16 @@
+apiVersion: v1
+entries:
+  alpine:
+    - name: alpine
+      urls:
+        - alpine-1.2.3.tgz
+      checksum: 0e6661f193211d7a5206918d42f5c2a9470b737d
+      home: https://k8s.io/helm
+      sources:
+      - https://github.com/kubernetes/helm
+      version: 1.2.3
+      description: Deploy a basic Alpine Linux pod
+      keywords: []
+      maintainers: []
+      engine: ""
+      icon: ""

pkg/downloader/testdata/helmhome/repository/repositories.yaml

@@ -10,3 +10,5 @@ repositories:
     url: "http://example.com/charts"
   - name: malformed
     url: "http://dl.example.com"
+  - name: testing-querystring
+    url: "http://example.com?key=value"

pkg/repo/chartrepo.go

@@ -110,8 +110,13 @@ func (r *ChartRepository) Load() error {
 // is for pre-2.2.0 repo files.
 func (r *ChartRepository) DownloadIndexFile(cachePath string) error {
 	var indexURL string
+	parsedURL, err := url.Parse(r.Config.URL)
+	if err != nil {
+		return err
+	}
+	parsedURL.Path = strings.TrimSuffix(parsedURL.Path, "/") + "/index.yaml"
 
-	indexURL = strings.TrimSuffix(r.Config.URL, "/") + "/index.yaml"
+	indexURL = parsedURL.String()
 	resp, err := r.Client.Get(indexURL)
 	if err != nil {
 		return err