feat: remove prepend when sending to frontend

Author: heyzec

src/commands/showPanel.tsx

@@ -15,7 +15,7 @@ import { FRONTEND_ELEMENT_ID } from "../constants";
 import { client, SOURCE_ACADEMY_ICON_URI } from "../extension";
 import _ from "lodash";
 import { treeDataProvider } from "../treeview";
-import { getNumPrependLines } from "../utils/editorUtils";
+import { codeRemovePrepend, getNumPrependLines } from "../utils/editorUtils";
 
 let panel: vscode.WebviewPanel | null = null;
 // This needs to be a reference to active
@@ -78,8 +78,10 @@ async function handleMessage(
               `EXTENSION: Editor ${editor.assessmentName}_${editor.questionId} is no longer active, skipping onChange`,
             );
           }
-          const message = Messages.Text(workspaceLocation, code);
-          console.log(`Sending message: ${JSON.stringify(message)}`);
+          const message = Messages.Text(
+            workspaceLocation,
+            codeRemovePrepend(code),
+          );
           sendToFrontend(panel, message);
         });
         break;

src/utils/editor.ts

@@ -6,7 +6,7 @@ import Messages, { VscWorkspaceLocation } from "./messages";
 import path from "path";
 import { sendToFrontendWrapped } from "../commands/showPanel";
 import { canonicaliseLocation } from "./misc";
-import { codeAddPrepend } from "./editorUtils";
+import { codeAddPrepend, codeRemovePrepend } from "./editorUtils";
 
 export class Editor {
   editor?: vscode.TextEditor;
@@ -64,48 +64,51 @@ export class Editor {
 
     const contents = codeAddPrepend(initialCode, prepend);
 
-    await vscode.workspace.fs.readFile(vscode.Uri.file(filePath)).then(
-      (value) => {
-        if (value.toString() !== contents) {
-          self.log(
-            "EXTENSION: Conflict detected between local and remote, prompting user to choose one",
+    await vscode.workspace.fs
+      .readFile(vscode.Uri.file(filePath))
+      .then((value) => value.toString())
+      .then(
+        (localCode) => {
+          if (localCode !== contents) {
+            self.log(
+              "EXTENSION: Conflict detected between local and remote, prompting user to choose one",
+            );
+            vscode.window
+              .showInformationMessage(
+                [
+                  "The local file differs from the version on the Source Academy servers.",
+                  "Discard the local file and use the one on the server?",
+                ].join(" "),
+                { modal: true },
+                "Yes",
+              )
+              .then(async (answer) => {
+                // By default the code displayed is the local one
+                if (answer === "Yes") {
+                  self.log("EXTENSION: Saving program from server to file");
+                  await vscode.workspace.fs.writeFile(
+                    uri,
+                    new TextEncoder().encode(contents),
+                  );
+                } else if (answer === undefined) {
+                  // Modal cancelled
+                  const message = Messages.Text(
+                    self.workspaceLocation,
+                    codeRemovePrepend(localCode),
+                  );
+                  sendToFrontendWrapped(message);
+                }
+              });
+          }
+        },
+        async () => {
+          self.log(`Opening file failed, creating at ${filePath}`);
+          await vscode.workspace.fs.writeFile(
+            uri,
+            new TextEncoder().encode(contents),
           );
-          vscode.window
-            .showInformationMessage(
-              [
-                "The local file differs from the version on the Source Academy servers.",
-                "Discard the local file and use the one on the server?",
-              ].join(" "),
-              { modal: true },
-              "Yes",
-            )
-            .then(async (answer) => {
-              // By default the code displayed is the local one
-              if (answer === "Yes") {
-                self.log("EXTENSION: Saving program from server to file");
-                await vscode.workspace.fs.writeFile(
-                  uri,
-                  new TextEncoder().encode(contents),
-                );
-              } else if (answer === undefined) {
-                // Modal cancelled
-                const message = Messages.Text(
-                  self.workspaceLocation,
-                  value.toString(),
-                );
-                sendToFrontendWrapped(message);
-              }
-            });
-        }
-      },
-      async () => {
-        self.log(`Opening file failed, creating at ${filePath}`);
-        await vscode.workspace.fs.writeFile(
-          uri,
-          new TextEncoder().encode(contents),
-        );
-      },
-    );
+        },
+      );
 
     const editor = await vscode.window.showTextDocument(uri, {
       preview: false,

src/utils/editorUtils.ts

@@ -27,3 +27,18 @@ export function getNumPrependLines(prepend: string) {
   }
   return prepend.split("\n").length + 3; // account for start/end markers
 }
+
+export function codeRemovePrepend(code: string) {
+  const lines = code.split("\n");
+  const start = lines.indexOf(PREPEND_MARKER_START);
+  const end = lines.indexOf(PREPEND_MARKER_END);
+
+  if (start === -1 || end === -1 || end < start) {
+    return code;
+  }
+
+  // If line spacing between prepend and code accidentally removed, do not delete code!
+  const skip = end + (lines[end + 1] === "" ? 1 : 0);
+
+  return lines.slice(skip + 1).join("\n");
+}