Suggest file system items correctly when an absolute path is used

CHANGELOG.md

@@ -28,6 +28,8 @@ All notable changes to the Docker Language Server will be documented in this fil
   - textDocument/hover
     - ignore 4XX errors when hovering over images with a non-standard tag ([#371](https://github.com/docker/docker-language-server/issues/371))
 - Compose
+  - textDocument/completion
+    - correct file system suggestions if an absolute path is used ([#443](https://github.com/docker/docker-language-server/issues/443))
   - textDocument/documentLink
     - stop returning links for alias nodes in included paths ([#439](https://github.com/docker/docker-language-server/issues/439))
 - Bake

internal/compose/completion_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"
 	"time"
@@ -4995,6 +4996,63 @@ services:
 	}
 }
 
+func testCompletion_RootFolder(t *testing.T, composeFileURI, rootDir, content string, line, character protocol.UInteger) {
+	entries, err := os.ReadDir(rootDir)
+	require.NoError(t, err, "could not read root directory %v", rootDir)
+	require.True(t, len(entries) > 0, "no entries in %v which makes it hard to validate this test", rootDir)
+	items := make([]protocol.CompletionItem, len(entries))
+	for i := range entries {
+		items[i] = protocol.CompletionItem{Label: entries[i].Name()}
+		if entries[i].IsDir() {
+			items[i].Kind = types.CreateCompletionItemKindPointer(protocol.CompletionItemKindFolder)
+		} else if entries[i].Type() == os.ModeSymlink {
+			items[i].Kind = types.CreateCompletionItemKindPointer(protocol.CompletionItemKindReference)
+		} else {
+			items[i].Kind = types.CreateCompletionItemKindPointer(protocol.CompletionItemKindFile)
+		}
+	}
+
+	manager := document.NewDocumentManager()
+	hub := hub.NewService()
+	doc := document.NewComposeDocument(manager, uri.URI(composeFileURI), 1, []byte(content))
+	list, err := Completion(context.Background(), &protocol.CompletionParams{
+		TextDocumentPositionParams: protocol.TextDocumentPositionParams{
+			TextDocument: protocol.TextDocumentIdentifier{URI: composeFileURI},
+			Position:     protocol.Position{Line: line, Character: character},
+		},
+	}, manager, &hub, doc)
+	require.NoError(t, err)
+	require.Equal(t, &protocol.CompletionList{Items: items}, list)
+}
+
+func TestCompletion_RootFolder(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("skipping on windows as / is not a root folder on Windows")
+		return
+	}
+
+	composeFileURI := fmt.Sprintf("file://%v", filepath.Join(os.TempDir(), "compose.yaml"))
+	testCompletion_RootFolder(t, composeFileURI, "/", `
+services:
+  s:
+    volumes:
+      - /`, 4, 9)
+}
+
+func TestCompletion_WindowsRootFolder(t *testing.T) {
+	if runtime.GOOS != "windows" {
+		t.Skip("skipping on non-Windows systems as it will not have a C:\\ folder")
+		return
+	}
+
+	composeFileURI := fmt.Sprintf("file:///%v", filepath.Join(os.TempDir(), "compose.yaml"))
+	testCompletion_RootFolder(t, composeFileURI, "C:\\", `
+services:
+  s:
+    volumes:
+      - C:\`, 4, 11)
+}
+
 func TestCompletion_FileStructure(t *testing.T) {
 	testCases := []struct {
 		name      string

internal/pkg/document/document.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/url"
 	"strings"
+	"unicode"
 
 	"github.com/docker/docker-language-server/internal/tliron/glsp/protocol"
 	"github.com/docker/docker-language-server/internal/types"
@@ -39,13 +40,27 @@ func NewDocument(mgr *Manager, u uri.URI, identifier protocol.LanguageIdentifier
 	return NewDockerfileDocument(u, version, input)
 }
 
+// DirectoryForPrefix returns the parent directory to be used given the
+// document's path and the prefix string that has been inserted into the
+// document thus far.
+//
+// prefixRequired is true if prefix can just be a name without any
+// slashes or backslashes.
 func DirectoryForPrefix(documentPath DocumentPath, prefix, defaultValue string, prefixRequired bool) string {
 	idx := strings.LastIndex(prefix, "/")
 	if idx == -1 {
 		if prefixRequired {
+			if len(prefix) > 2 && unicode.IsLetter(rune(prefix[0])) && prefix[1] == ':' {
+				backslashIdx := strings.LastIndex(prefix, "\\")
+				if backslashIdx != -1 {
+					return prefix[0 : backslashIdx+1]
+				}
+			}
 			return defaultValue
 		}
 		return documentPath.Folder
+	} else if prefix[0] == '/' {
+		return prefix[0 : idx+1]
 	}
 	_, folder := types.Concatenate(documentPath.Folder, prefix[0:idx], documentPath.WSLDollarSignHost)
 	return folder

internal/types/common.go

@@ -124,6 +124,10 @@ func FileStructureCompletionItems(folder string, hideFiles bool) []protocol.Comp
 				item := protocol.CompletionItem{Label: entry.Name()}
 				item.Kind = CreateCompletionItemKindPointer(protocol.CompletionItemKindFolder)
 				items = append(items, item)
+			} else if entry.Type() == os.ModeSymlink {
+				item := protocol.CompletionItem{Label: entry.Name()}
+				item.Kind = CreateCompletionItemKindPointer(protocol.CompletionItemKindReference)
+				items = append(items, item)
 			} else if !hideFiles {
 				item := protocol.CompletionItem{Label: entry.Name()}
 				item.Kind = CreateCompletionItemKindPointer(protocol.CompletionItemKindFile)