gopls/internal/golang: strip @v1.2.3 suffix from pkgdoc URLs

The  package path in a /pkg URL does not want a module
version suffix: the view specifies the versions of all packages.
Remove them.

Fixes golang/go#68116

Change-Id: Icbe7a6e7346d12456724d005fe8f755872657055
Reviewed-on: https://go-review.googlesource.com/c/tools/+/594556
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>

gopls/internal/golang/hover.go

@@ -70,6 +70,7 @@ type hoverJSON struct {
 
 	// LinkPath is the pkg.go.dev link for the given symbol.
 	// For example, the "go/ast" part of "pkg.go.dev/go/ast#Node".
+	// It may have a module version suffix "@v1.2.3".
 	LinkPath string `json:"linkPath"`
 
 	// LinkAnchor is the pkg.go.dev link anchor for the given symbol.
@@ -98,6 +99,7 @@ type hoverJSON struct {
 }
 
 // Hover implements the "textDocument/hover" RPC for Go files.
+// It may return nil even on success.
 //
 // If pkgURL is non-nil, it should be used to generate doc links.
 func Hover(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, position protocol.Position, pkgURL func(path PackagePath, fragment string) protocol.URI) (*protocol.Hover, error) {
@@ -200,7 +202,7 @@ func hover(ctx context.Context, snapshot *cache.Snapshot, fh file.Handle, pp pro
 			if hoverRange == nil {
 				hoverRange = &rng
 			}
-			return *hoverRange, hoverJSON, nil
+			return *hoverRange, hoverJSON, nil // (hoverJSON may be nil)
 		}
 	}
 	// Handle hovering over (non-import-path) literals.
@@ -1159,7 +1161,8 @@ func formatLink(h *hoverJSON, options *settings.Options, pkgURL func(path Packag
 	var url protocol.URI
 	var caption string
 	if pkgURL != nil { // LinksInHover == "gopls"
-		url = pkgURL(PackagePath(h.LinkPath), h.LinkAnchor)
+		path, _, _ := strings.Cut(h.LinkPath, "@") // remove optional module version suffix
+		url = pkgURL(PackagePath(path), h.LinkAnchor)
 		caption = "in gopls doc viewer"
 	} else {
 		if options.LinkTarget == "" {

gopls/internal/test/integration/fake/editor.go

@@ -1595,6 +1595,7 @@ func (e *Editor) EditResolveSupport() (bool, error) {
 }
 
 // Hover triggers a hover at the given position in an open buffer.
+// It may return (nil, zero) if no symbol was selected.
 func (e *Editor) Hover(ctx context.Context, loc protocol.Location) (*protocol.MarkupContent, protocol.Location, error) {
 	if err := e.checkBufferLocation(loc); err != nil {
 		return nil, protocol.Location{}, err
@@ -1608,7 +1609,7 @@ func (e *Editor) Hover(ctx context.Context, loc protocol.Location) (*protocol.Ma
 		return nil, protocol.Location{}, fmt.Errorf("hover: %w", err)
 	}
 	if resp == nil {
-		return nil, protocol.Location{}, nil
+		return nil, protocol.Location{}, nil // e.g. no selected symbol
 	}
 	return &resp.Contents, protocol.Location{URI: loc.URI, Range: resp.Range}, nil
 }

gopls/internal/test/integration/misc/hover_test.go

@@ -553,3 +553,53 @@ func main() {
 		})
 	}
 }
+
+func TestHoverInternalLinksIssue68116(t *testing.T) {
+	// Links for the internal viewer should not include a module version suffix:
+	// the package path and the view are an unambiguous key; see #68116.
+
+	const proxy = `
+-- example.com@v1.2.3/go.mod --
+module example.com
+
+go 1.12
+
+-- example.com@v1.2.3/a/a.go --
+package a
+
+// F is a function.
+func F()
+`
+
+	const mod = `
+-- go.mod --
+module main
+
+go 1.12
+
+require example.com v1.2.3
+
+-- main.go --
+package main
+
+import "example.com/a"
+
+func main() {
+	a.F()
+}
+`
+	WithOptions(
+		ProxyFiles(proxy),
+		Settings{"linksInHover": "gopls"},
+		WriteGoSum("."),
+	).Run(t, mod, func(t *testing.T, env *Env) {
+		env.OpenFile("main.go")
+		got, _ := env.Hover(env.RegexpSearch("main.go", "F"))
+		const wantRE = "\\[`a.F` in gopls doc viewer\\]\\(http://127.0.0.1:[0-9]+/gopls/[^/]+/pkg/example.com\\?view=[0-9]+#F\\)" // no version
+		if m, err := regexp.MatchString(wantRE, got.Value); err != nil {
+			t.Fatalf("bad regexp in test: %v", err)
+		} else if !m {
+			t.Fatalf("hover output does not match %q; got:\n\n%s", wantRE, got.Value)
+		}
+	})
+}

gopls/internal/test/integration/wrappers.go

@@ -233,6 +233,7 @@ func (e *Env) GetQuickFixes(path string, diagnostics []protocol.Diagnostic) []pr
 }
 
 // Hover in the editor, calling t.Fatal on any error.
+// It may return (nil, zero) even on success.
 func (e *Env) Hover(loc protocol.Location) (*protocol.MarkupContent, protocol.Location) {
 	e.T.Helper()
 	c, loc, err := e.Editor.Hover(e.Ctx, loc)