Fix URI parsing for Windows paths

internal/filesystem/file.go

@@ -24,8 +24,6 @@ func NewFile(fullPath string, content []byte) *file {
 	return &file{fullPath: fullPath, content: content}
 }
 
-const uriPrefix = "file://"
-
 func (f *file) FullPath() string {
 	return f.fullPath
 }
@@ -39,7 +37,7 @@ func (f *file) Filename() string {
 }
 
 func (f *file) URI() string {
-	return uriPrefix + f.fullPath
+	return URIFromPath(f.fullPath)
 }
 
 func (f *file) Lines() source.Lines {

internal/filesystem/uri.go

@@ -0,0 +1,17 @@
+package filesystem
+
+import (
+	"net/url"
+	"path/filepath"
+)
+
+func URIFromPath(path string) string {
+	p := filepath.ToSlash(path)
+	p = wrapPath(p)
+
+	u := &url.URL{
+		Scheme: "file",
+		Path:   p,
+	}
+	return u.String()
+}

internal/filesystem/uri_unix.go

@@ -0,0 +1,8 @@
+// +build !windows
+
+package filesystem
+
+// wrapPath is no-op for unix-style paths
+func wrapPath(path string) string {
+	return path
+}

internal/filesystem/uri_unix_test.go

@@ -0,0 +1,18 @@
+// +build !windows
+
+package filesystem
+
+import (
+	"testing"
+)
+
+func TestURIFromPath(t *testing.T) {
+	path := "/random/path"
+	uri := URIFromPath(path)
+
+	expectedURI := "file:///random/path"
+	if uri != expectedURI {
+		t.Fatalf("URI doesn't match.\nExpected: %q\nGiven: %q",
+			expectedURI, uri)
+	}
+}

internal/filesystem/uri_windows.go

@@ -0,0 +1,8 @@
+package filesystem
+
+// wrapPath prepends Windows-style paths (C:\path)
+// with an additional slash to account for an empty hostname
+// in a valid file-scheme URI per RFC 8089
+func wrapPath(path string) string {
+	return "/" + path
+}

internal/filesystem/uri_windows_test.go

@@ -0,0 +1,16 @@
+package filesystem
+
+import (
+	"testing"
+)
+
+func TestURIFromPath(t *testing.T) {
+	path := `C:\Users\With Space\file.tf`
+	uri := URIFromPath(path)
+
+	expectedURI := "file:///C:/Users/With%20Space/file.tf"
+	if uri != expectedURI {
+		t.Fatalf("URI doesn't match.\nExpected: %q\nGiven: %q",
+			expectedURI, uri)
+	}
+}

internal/lsp/file_handler.go

@@ -3,36 +3,40 @@ package lsp
 import (
 	"net/url"
 	"path/filepath"
-	"strings"
 
+	"github.com/hashicorp/terraform-ls/internal/filesystem"
 	"github.com/sourcegraph/go-lsp"
 )
 
-const uriPrefix = "file://"
-
 type FileHandler string
 
 func (fh FileHandler) Valid() bool {
-	if !strings.HasPrefix(string(fh), uriPrefix) {
-		return false
-	}
-	p := string(fh[len(uriPrefix):])
-	_, err := url.PathUnescape(p)
+	_, err := fh.parsePath()
 	if err != nil {
 		return false
 	}
+
 	return true
 }
 
 func (fh FileHandler) FullPath() string {
-	if !fh.Valid() {
+	p, err := fh.parsePath()
+	if err != nil {
 		panic("invalid uri")
 	}
-	p := string(fh[len(uriPrefix):])
-	p, _ = url.PathUnescape(p)
+
 	return filepath.FromSlash(p)
 }
 
+func (fh FileHandler) parsePath() (string, error) {
+	u, err := url.ParseRequestURI(string(fh))
+	if err != nil {
+		return "", err
+	}
+
+	return url.PathUnescape(u.Path)
+}
+
 func (fh FileHandler) Dir() string {
 	return filepath.Dir(fh.FullPath())
 }
@@ -66,5 +70,5 @@ func (fh *versionedFileHandler) Version() int {
 }
 
 func FileHandlerFromPath(path string) FileHandler {
-	return FileHandler(uriPrefix + filepath.ToSlash(path))
+	return FileHandler(filesystem.URIFromPath(path))
 }

internal/lsp/file_handler_windows_test.go

@@ -11,7 +11,7 @@ func TestFileHandler_valid_windows(t *testing.T) {
 		t.Fatalf("Expected %q to be valid", path)
 	}
 
-	expectedDir := `\C:\Users\With Space\tf-test`
+	expectedDir := `C:\Users\With Space\tf-test`
 	if fh.Dir() != expectedDir {
 		t.Fatalf("Expected dir: %q, given: %q",
 			expectedDir, fh.Dir())
@@ -23,7 +23,7 @@ func TestFileHandler_valid_windows(t *testing.T) {
 			expectedFilename, fh.Filename())
 	}
 
-	expectedFullPath := `\C:\Users\With Space\tf-test\file.tf`
+	expectedFullPath := `C:\Users\With Space\tf-test\file.tf`
 	if fh.FullPath() != expectedFullPath {
 		t.Fatalf("Expected full path: %q, given: %q",
 			expectedFullPath, fh.FullPath())