Show links for short-form volumes that reference local files

Signed-off-by: Remy Suen <remy.suen@docker.com>

Author: rcjsuen

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 All notable changes to the Docker Language Server will be documented in this file.
 
+## [Unreleased]
+
+### Fixed
+
+- Compose
+  - textDocument/documentLink
+    - return document links for files referenced in the short-form `volumes` attribute of a service object ([#460](https://github.com/docker/docker-language-server/issues/460))
+
 ## [0.18.0] - 2025-08-25
 
 ### Added

internal/compose/documentLink.go

@@ -3,8 +3,12 @@ package compose
 import (
 	"context"
 	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 
+	"github.com/compose-spec/compose-go/v2/format"
+	composeTypes "github.com/compose-spec/compose-go/v2/types"
 	"github.com/docker/docker-language-server/internal/pkg/document"
 	"github.com/docker/docker-language-server/internal/tliron/glsp/protocol"
 	"github.com/docker/docker-language-server/internal/types"
@@ -104,6 +108,40 @@ func createFileLinks(folderAbsolutePath string, wslDollarSign bool, serviceNode
 	return nil
 }
 
+func createVolumeFileLinks(folderAbsolutePath string, wslDollarSign bool, serviceNode *ast.MappingValueNode) []protocol.DocumentLink {
+	if resolveAnchor(serviceNode.Key).GetToken().Value == "volumes" {
+		if sequence, ok := resolveAnchor(serviceNode.Value).(*ast.SequenceNode); ok {
+			links := []protocol.DocumentLink{}
+			for _, node := range sequence.Values {
+				if s, ok := resolveAnchor(node).(*ast.StringNode); ok {
+					config, err := format.ParseVolume(s.GetToken().Value)
+					if err == nil && config.Type == composeTypes.VolumeTypeBind {
+						uri, path := createLocalFileLink(folderAbsolutePath, config.Source, wslDollarSign)
+						info, err := os.Stat(path)
+						if err == nil && !info.IsDir() {
+							t := volumeToken(s.GetToken())
+							links = append(links, protocol.DocumentLink{
+								Range:   createRange(t, len(t.Value)),
+								Target:  types.CreateStringPointer(uri),
+								Tooltip: types.CreateStringPointer(path),
+							})
+						}
+					}
+				}
+			}
+			return links
+		}
+	}
+	return nil
+}
+
+func createLocalFileLink(folderAbsolutePath, fsPath string, wslDollarSign bool) (uri, path string) {
+	if filepath.IsAbs(fsPath) {
+		return fmt.Sprintf("file:///%v", strings.TrimPrefix(filepath.ToSlash(fsPath), "/")), fsPath
+	}
+	return types.Concatenate(folderAbsolutePath, fsPath, wslDollarSign)
+}
+
 func createObjectFileLink(folderAbsolutePath string, wslDollarSign bool, serviceNode *ast.MappingValueNode) *protocol.DocumentLink {
 	if resolveAnchor(serviceNode.Key).GetToken().Value == "file" {
 		return createFileLink(folderAbsolutePath, wslDollarSign, serviceNode)
@@ -216,6 +254,9 @@ func scanForLinks(folderAbsolutePath string, wslDollarSign bool, n *ast.MappingV
 
 							labelFileLinks := createFileLinks(folderAbsolutePath, wslDollarSign, serviceAttribute, "label_file")
 							links = append(links, labelFileLinks...)
+
+							volumeFileLinks := createVolumeFileLinks(folderAbsolutePath, wslDollarSign, serviceAttribute)
+							links = append(links, volumeFileLinks...)
 						}
 					}
 				}

internal/compose/documentLink_test.go

@@ -2035,6 +2035,118 @@ services:
 	}
 }
 
+func TestDocumentLink_VolumeFileLinks(t *testing.T) {
+	tempDir := os.TempDir()
+	tempFile := filepath.Join(tempDir, "tempFile.txt")
+	f, err := os.Create(tempFile)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		require.NoError(t, f.Close())
+	})
+	testsFolder := createFileStructure(t)
+	composeStringURI := fmt.Sprintf("file:///%v", strings.TrimPrefix(filepath.ToSlash(filepath.Join(testsFolder, "compose.yaml")), "/"))
+
+	testCases := []struct {
+		name      string
+		content   string
+		path      string
+		linkRange protocol.Range
+	}{
+		{
+			name: "mount local file",
+			content: `
+services:
+  test:
+    volumes:
+      - ./a.txt:/mount/a.txt`,
+			path: filepath.Join(testsFolder, "./a.txt"),
+			linkRange: protocol.Range{
+				Start: protocol.Position{Line: 4, Character: 8},
+				End:   protocol.Position{Line: 4, Character: 15},
+			},
+		},
+		{
+			name: "mount local file (string is anchored)",
+			content: `
+services:
+  test:
+    volumes:
+      - &anchor ./a.txt:/mount/a.txt`,
+			path: filepath.Join(testsFolder, "./a.txt"),
+			linkRange: protocol.Range{
+				Start: protocol.Position{Line: 4, Character: 16},
+				End:   protocol.Position{Line: 4, Character: 23},
+			},
+		},
+		{
+			name: "mount local file (volumes attribute name is anchored)",
+			content: `
+services:
+  test:
+    &anchor volumes:
+      - ./a.txt:/mount/a.txt`,
+			path: filepath.Join(testsFolder, "./a.txt"),
+			linkRange: protocol.Range{
+				Start: protocol.Position{Line: 4, Character: 8},
+				End:   protocol.Position{Line: 4, Character: 15},
+			},
+		},
+		{
+			name: "mount local file (volumes attribute value is anchored)",
+			content: `
+services:
+  test:
+    volumes: &anchor
+      - ./a.txt:/mount/a.txt`,
+			path: filepath.Join(testsFolder, "./a.txt"),
+			linkRange: protocol.Range{
+				Start: protocol.Position{Line: 4, Character: 8},
+				End:   protocol.Position{Line: 4, Character: 15},
+			},
+		},
+		{
+			name: "mount local folder",
+			content: `
+services:
+  test:
+    volumes:
+      - ./folder:/mount/folder`,
+		},
+		{
+			name: "absolute path",
+			content: fmt.Sprintf(`
+services:
+  test:
+    volumes:
+      - %v:/mount/file.txt`, tempFile),
+			path: tempFile,
+			linkRange: protocol.Range{
+				Start: protocol.Position{Line: 4, Character: 8},
+				End:   protocol.Position{Line: 4, Character: protocol.UInteger(8 + len(tempFile))},
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			mgr := document.NewDocumentManager()
+			doc := document.NewComposeDocument(mgr, uri.URI(composeStringURI), 1, []byte(tc.content))
+			links, err := DocumentLink(context.Background(), composeStringURI, doc)
+			require.NoError(t, err)
+			if tc.path == "" {
+				require.Equal(t, []protocol.DocumentLink{}, links)
+			} else {
+				link := protocol.DocumentLink{
+					Range:   tc.linkRange,
+					Target:  types.CreateStringPointer(fmt.Sprintf("file:///%v", strings.TrimPrefix(filepath.ToSlash(tc.path), "/"))),
+					Tooltip: types.CreateStringPointer(filepath.FromSlash(tc.path)),
+				}
+				require.Equal(t, []protocol.DocumentLink{link}, links)
+			}
+		})
+	}
+}
+
 func TestDocumentLink_ConfigFileLinks(t *testing.T) {
 	testsFolder := filepath.Join(os.TempDir(), t.Name())
 	composeStringURI := fmt.Sprintf("file:///%v", strings.TrimPrefix(filepath.ToSlash(filepath.Join(testsFolder, "compose.yaml")), "/"))