From e5c80a793d416edbfa6e7e457f29cf249b654b11 Mon Sep 17 00:00:00 2001
From: Remy Suen <remy.suen@docker.com>
Date: Fri, 21 Nov 2025 03:56:59 +0000
Subject: [PATCH] Ignore empty prefixes when processing image tag completions

Signed-off-by: Remy Suen <remy.suen@docker.com>
---
 CHANGELOG.md                        |  3 +++
 internal/compose/completion.go      |  2 +-
 internal/compose/completion_test.go | 20 ++++++++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f8f4aef..3d18067 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,9 @@ All notable changes to the Docker Language Server will be documented in this fil
 
 ### Fixed
 
+- Compose
+  - textDocument/completion
+    - check the prefix string before trying to use it for looking up image tags ([#486](https://github.com/docker/docker-language-server/issues/486))
 - Bake
   - fix parsing error caused by referencing a variable with no value ([#490](https://github.com/docker/docker-language-server/issues/490))
 
diff --git a/internal/compose/completion.go b/internal/compose/completion.go
index fb520c9..610fcfe 100644
--- a/internal/compose/completion.go
+++ b/internal/compose/completion.go
@@ -582,7 +582,7 @@ func buildTargetCompletionItems(params *protocol.CompletionParams, manager *docu
 }
 
 func serviceImageCompletionItems(hub hub.Service, path []*ast.MappingValueNode, prefix string) ([]protocol.CompletionItem, bool) {
-	if len(path) == 3 && path[0].Key.GetToken().Value == "services" && path[2].Key.GetToken().Value == "image" {
+	if len(path) == 3 && path[0].Key.GetToken().Value == "services" && path[2].Key.GetToken().Value == "image" && len(prefix) > 0 {
 		if path[2].Value.GetToken().Type == token.DoubleQuoteType || path[2].Value.GetToken().Type == token.SingleQuoteType {
 			prefix = prefix[1:]
 		}
diff --git a/internal/compose/completion_test.go b/internal/compose/completion_test.go
index 6383370..5c46170 100644
--- a/internal/compose/completion_test.go
+++ b/internal/compose/completion_test.go
@@ -5509,6 +5509,26 @@ services:
 			character: 15,
 			list:      nil,
 		},
+		{
+			name: "single quoted completion with whitespace preceding the character position",
+			content: `
+services:
+  test:
+    image: ' '`,
+			line:      3,
+			character: 13,
+			list:      nil,
+		},
+		{
+			name: "double quoted completion with whitespace preceding the character position",
+			content: `
+services:
+  test:
+    image: " "`,
+			line:      3,
+			character: 13,
+			list:      nil,
+		},
 	}
 
 	dir := createFileStructure(t)