EDITOR: Improved infinite loop checking (#1276)

src/Documentation/doc/basic/scripts.md

@@ -62,6 +62,21 @@ For example, if a script run with 1 thread is able to hack \$10,000, then runnin
 
 When "multithreading" a script, the total [RAM](ram.md) cost can be calculated by simply multiplying the [RAM](ram.md) cost of a single instance of your script by the number of threads you will use. [See [`ns.getScriptRam()`](https://github.com/bitburner-official/bitburner-src/blob/bec737a25307be29c7efef147fc31effca65eedc/markdown/bitburner.ns.getscriptram.md) or the `mem` terminal command detailed below]
 
+## Never-ending scripts
+
+Sometimes it might be necessary for a script to never end and keep doing a particular task.
+In that case you would want to write your script in a never-ending loop, like `while (true)`.
+
+However, if you are not careful, this can crash your game.
+If the code inside the loop doesn't `await` for some time, it will never give other scripts and the game itself time to process.
+
+<br />
+
+To help you find this potential bug, any `while (true)` loop without any `await` statement inside it will be marked.
+A red decoration will appear on the left side of the script editor, telling you about the issue.
+
+If you are really sure that this is not an oversight, you can suppress the warning using the comment `// @ignore-infinite` directly above the loop.
+
 ## Working with Scripts in Terminal
 
 Here are some [terminal](terminal.md) commands you will find useful when working with scripts:

src/Script/RamCalculations.ts

@@ -199,16 +199,16 @@ function parseOnlyRamCalculate(otherScripts: Map<ScriptFilePath, Script>, code:
   return { cost: ram, entries: detailedCosts.filter((e) => e.cost > 0) };
 }
 
-export function checkInfiniteLoop(code: string): number {
+export function checkInfiniteLoop(code: string): number[] {
   let ast: acorn.Node;
   try {
     ast = parse(code, { sourceType: "module", ecmaVersion: "latest" });
   } catch (e) {
     // If code cannot be parsed, do not provide infinite loop detection warning
-    return -1;
+    return [];
   }
   function nodeHasTrueTest(node: acorn.Node): boolean {
-    return node.type === "Literal" && "raw" in node && node.raw === "true";
+    return node.type === "Literal" && "raw" in node && (node.raw === "true" || node.raw === "1");
   }
 
   function hasAwait(ast: acorn.Node): boolean {
@@ -225,14 +225,19 @@ export function checkInfiniteLoop(code: string): number {
     return hasAwait;
   }
 
-  let missingAwaitLine = -1;
+  const possibleLines: number[] = [];
   walk.recursive(
     ast,
     {},
     {
       WhileStatement: (node: Node, st: unknown, walkDeeper: walk.WalkerCallback<any>) => {
+        const previousLines = code.slice(0, node.start).trimEnd().split("\n");
+        const lineNumber = previousLines.length + 1;
+        if (previousLines[previousLines.length - 1].match(/^\s*\/\/\s*@ignore-infinite/)) {
+          return;
+        }
         if (nodeHasTrueTest(node.test) && !hasAwait(node)) {
-          missingAwaitLine = (code.slice(0, node.start).match(/\n/g) || []).length + 1;
+          possibleLines.push(lineNumber);
         } else {
           node.body && walkDeeper(node.body, st);
         }
@@ -240,7 +245,7 @@ export function checkInfiniteLoop(code: string): number {
     },
   );
 
-  return missingAwaitLine;
+  return possibleLines;
 }
 
 interface ParseDepsResult {

src/ScriptEditor/ui/ScriptEditorRoot.tsx

@@ -116,10 +116,10 @@ function Root(props: IProps): React.ReactElement {
     if (editorRef.current === null || currentScript === null) return;
     if (!decorations) decorations = editorRef.current.createDecorationsCollection();
     if (!currentScript.path.endsWith(".js")) return;
-    const awaitWarning = checkInfiniteLoop(newCode);
-    if (awaitWarning !== -1) {
-      decorations.set([
-        {
+    const possibleLines = checkInfiniteLoop(newCode);
+    if (possibleLines.length !== 0) {
+      decorations.set(
+        possibleLines.map((awaitWarning) => ({
           range: {
             startLineNumber: awaitWarning,
             startColumn: 1,
@@ -130,11 +130,12 @@ function Root(props: IProps): React.ReactElement {
             isWholeLine: true,
             glyphMarginClassName: "myGlyphMarginClass",
             glyphMarginHoverMessage: {
-              value: "Possible infinite loop, await something.",
+              value:
+                "Possible infinite loop, await something. If this is a false-positive, use `// @ignore-infinite` to suppress.",
             },
           },
-        },
-      ]);
+        })),
+      );
     } else decorations.clear();
   }