Fix #258 Correct error response in COPY completion items

If textDocument/completion is received at the end of a COPY instruction
with flags, an error response will no longer be sent back.

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

CHANGELOG.md

@@ -1,6 +1,11 @@
 # Changelog
 All notable changes to this project will be documented in this file.
 
+## [Unreleased]
+### Fixed
+- textDocument/completion
+  - fix error returned when computing completion items at the end of a COPY instruction with flags ([#258](https://github.com/rcjsuen/dockerfile-language-server-nodejs/issues/258))
+
 ## [0.7.2] - 2021-10-20
 ### Fixed
 - textDocument/semanticTokens/full

package.json

@@ -20,7 +20,7 @@
     "node": "*"
   },
   "dependencies": {
-    "dockerfile-language-service": "0.7.3",
+    "dockerfile-language-service": "0.7.4",
     "dockerfile-utils": "0.9.2",
     "vscode-languageserver": "^8.0.0-next.2"
   },

test/server.test.ts

@@ -2187,6 +2187,44 @@ describe("Dockerfile LSP Tests", function() {
 		});
 	});
 
+	it("issue #258", (finished) => {
+		const uri = "uri://dockerfile/258.txt";
+		this.timeout(5000);
+		sendNotification("textDocument/didOpen", {
+			textDocument: {
+				languageId: "dockerfile",
+				version: 1,
+				uri: uri,
+				text: "COPY --from=a "
+			}
+		});
+		let id = sendRequest("textDocument/completion", {
+			textDocument: { uri: uri },
+			position: { line: 0, character: 14 }
+		});
+
+		const listener258 = (json) => {
+			if (json.id === id) {
+				lspProcess.removeListener("message", listener258);
+				sendNotification("textDocument/didClose", {
+					textDocument: { uri: uri }
+				});
+				assert.strictEqual(json.result.length, 1);
+				assert.strictEqual(json.result[0].data, "COPY_FlagChown");
+				assert.strictEqual(json.result[0].label, "--chown=");
+				assert.strictEqual(json.result[0].kind, CompletionItemKind.Field);
+				assert.strictEqual(json.result[0].insertTextFormat, InsertTextFormat.PlainText);
+				assert.strictEqual(json.result[0].textEdit.newText, "--chown=");
+				assert.strictEqual(json.result[0].textEdit.range.start.line, 0);
+				assert.strictEqual(json.result[0].textEdit.range.start.character, 14);
+				assert.strictEqual(json.result[0].textEdit.range.end.line, 0);
+				assert.strictEqual(json.result[0].textEdit.range.end.character, 14);
+				finished();
+			}
+		};
+		lspProcess.on("message", listener258);
+	});
+
 	after(() => {
 		// terminate the forked LSP process after all the tests have been run
 		lspProcess.kill();