internal/span: handle file URLs with two slashes

Correct file URLs should have three slashes: two for the protocol
(file://) and one for the beginning of the path. Perhaps unsurprisingly,
VS Code is sending us URLs with only two. Add the third.

Fixes golang/go#39789

Change-Id: I922b3adf1d5980991a43229d952d77fecaf1366b
Reviewed-on: https://go-review.googlesource.com/c/tools/+/239743
Run-TryBot: Heschi Kreinick <[email protected]>
TryBot-Result: Gobot Gobot <[email protected]>
Reviewed-by: Rebecca Stambler <[email protected]>

Author: heschi

internal/span/uri.go

@@ -54,10 +54,14 @@ func filename(uri URI) (string, error) {
 }
 
 func URIFromURI(s string) URI {
-	if !strings.HasPrefix(s, "file:///") {
+	if !strings.HasPrefix(s, "file://") {
 		return URI(s)
 	}
 
+	if !strings.HasPrefix(s, "file:///") {
+		// VS Code sends URLs with only two slashes, which are invalid. golang/go#39789.
+		s = "file:///" + s[len("file://"):]
+	}
 	// Even though the input is a URI, it may not be in canonical form. VS Code
 	// in particular over-escapes :, @, etc. Unescape and re-encode to canonicalize.
 	path, err := url.PathUnescape(s[len("file://"):])

internal/span/uri_test.go

@@ -98,6 +98,11 @@ func TestURIFromURI(t *testing.T) {
 			wantFile: `/`,
 			wantURI:  span.URI(`file:///`),
 		},
+		{
+			inputURI: `file://wsl%24/Ubuntu/home/wdcui/repo/VMEnclaves/cvm-runtime`,
+			wantFile: `/wsl$/Ubuntu/home/wdcui/repo/VMEnclaves/cvm-runtime`,
+			wantURI:  span.URI(`file:///wsl$/Ubuntu/home/wdcui/repo/VMEnclaves/cvm-runtime`),
+		},
 	} {
 		got := span.URIFromURI(test.inputURI)
 		if got != test.wantURI {