Allow repos with URL-encoded paths

https://github.com/helm/helm/issues/9977

Repos that have URL-encoded characters in the path cause the "helm
install" command to fail. For example:

```
"purelb" has been added to your repositories
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "purelb" chart repository
Update Complete. ⎈ Happy Helming!⎈
install.go:158: [debug] Original chart version: ""
install.go:160: [debug] setting version to >0.0.0-0
Error: failed to fetch https://gitlab.com/api/v4/projects/purelb/purelb/packages/helm/stable/charts/purelb-v0.0.0-open-source-helm-chart-latest.tgz : 404 Not Found
helm.go:75: [debug] failed to fetch https://gitlab.com/api/v4/projects/purelb/purelb/packages/helm/stable/charts/purelb-v0.0.0-open-source-helm-chart-latest.tgz : 404 Not Found
helm.sh/helm/v3/pkg/getter.(*HTTPGetter).get
        /home/circleci/helm.sh/helm/pkg/getter/httpgetter.go:72
helm.sh/helm/v3/pkg/getter.(*HTTPGetter).Get
        /home/circleci/helm.sh/helm/pkg/getter/httpgetter.go:40
helm.sh/helm/v3/pkg/downloader.(*ChartDownloader).DownloadTo
        /home/circleci/helm.sh/helm/pkg/downloader/chart_downloader.go:97
helm.sh/helm/v3/pkg/action.(*ChartPathOptions).LocateChart
        /home/circleci/helm.sh/helm/pkg/action/install.go:738
main.runInstall
        /home/circleci/helm.sh/helm/cmd/helm/install.go:170
main.newInstallCmd.func1
        /home/circleci/helm.sh/helm/cmd/helm/install.go:117
github.com/spf13/cobra.(*Command).execute
        /go/pkg/mod/github.com/spf13/cobra@v0.0.5/command.go:826
github.com/spf13/cobra.(*Command).ExecuteC
        /go/pkg/mod/github.com/spf13/cobra@v0.0.5/command.go:914
github.com/spf13/cobra.(*Command).Execute
        /go/pkg/mod/github.com/spf13/cobra@v0.0.5/command.go:864
main.main
        /home/circleci/helm.sh/helm/cmd/helm/helm.go:74
runtime.main
        /usr/local/go/src/runtime/proc.go:203
runtime.goexit
        /usr/local/go/src/runtime/asm_amd64.s:1357

```
Note that the "purelb%2Fpurelb" in the original repo URL has been
un-escaped and is now "purelb/purelb".

It turns out that the golang net/url package gets confused if the Path
and RawPath fields diverge, and it looks like it throws away
RawPath. That's speculation on my part. In any case, setting *both*
Path and RawPath keeps the URL-encoding.

Signed-off-by: Chilton Cabot <toby@acnodal.io>
Signed-off-by: toby cabot <toby@acnodal.io>

pkg/downloader/chart_downloader.go

@@ -268,6 +268,9 @@ func (c *ChartDownloader) ResolveChartVersion(ref, version string) (*url.URL, er
 		q := repoURL.Query()
 		// We need a trailing slash for ResolveReference to work, but make sure there isn't already one
 		repoURL.Path = strings.TrimSuffix(repoURL.Path, "/") + "/"
+		// The URL class has problems with URL-escaped paths if we don't
+		// modify both paths. See https://github.com/helm/helm/issues/9977
+		repoURL.RawPath = strings.TrimSuffix(repoURL.RawPath, "/") + "/"
 		u = repoURL.ResolveReference(u)
 		u.RawQuery = q.Encode()
 		// TODO add user-agent

pkg/downloader/chart_downloader_test.go

@@ -49,6 +49,7 @@ func TestResolveChartRef(t *testing.T) {
 		{name: "reference, testing-relative repo", ref: "testing-relative/bar", expect: "http://example.com/helm/bar-1.2.3.tgz"},
 		{name: "reference, testing-relative-trailing-slash repo", ref: "testing-relative-trailing-slash/foo", expect: "http://example.com/helm/charts/foo-1.2.3.tgz"},
 		{name: "reference, testing-relative-trailing-slash repo", ref: "testing-relative-trailing-slash/bar", expect: "http://example.com/helm/bar-1.2.3.tgz"},
+		{name: "reference, testing-url-encoded-path repo", ref: "testing-url-encoded-path/foo", expect: "http://example.com/path%2fpath/charts/foo-1.2.3.tgz"},
 		{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/repositories.yaml

@@ -16,6 +16,8 @@ repositories:
     url: "http://example.com/helm"
   - name: testing-relative-trailing-slash
     url: "http://example.com/helm/"
+  - name: testing-url-encoded-path
+    url: "http://example.com/path%2fpath"
   - name: testing-ca-file
     url: "https://example.com"
     certFile: "cert"

pkg/downloader/testdata/repository/testing-url-encoded-path-index.yaml

@@ -0,0 +1,15 @@
+apiVersion: v1
+entries:
+  foo:
+    - name: foo
+      description: Foo Chart With URL-Encoded Path
+      home: https://helm.sh/helm
+      keywords: []
+      maintainers: []
+      sources:
+        - https://example.com/path%2fpath
+      urls:
+        - charts/foo-1.2.3.tgz
+      version: 1.2.3
+      checksum: 0e6661f193211d7a5206918d42f5c2a9470b737d
+      apiVersion: v2