wasm: simplify using DocumentProcessManager

DocumentProcessManager needs to be told when a Process crashes. Simplify
this interface by instead making DocumentProcessManager ask a Process if
it has crashed.

This commit should not change behavior.

Author: strager

wasm/quick-lint-js.js

@@ -76,7 +76,6 @@ class DocumentLinter {
         parser = process.createDocumentForVSCode();
       } catch (e) {
         if (e instanceof ProcessCrashed) {
-          this._documentProcessManager.processCrashed(process);
           throw new LintingCrashed(e);
         } else {
           throw e;
@@ -121,7 +120,6 @@ class DocumentLinter {
             this._parser.dispose();
           } catch (e) {
             if (e instanceof ProcessCrashed) {
-              this._documentProcessManager.processCrashed(this._parser.process);
               // Ignore.
             } else {
               throw e;
@@ -209,7 +207,6 @@ class DocumentLinter {
         } catch (e) {
           // END CRITICAL SECTION (no awaiting above)
           if (e instanceof ProcessCrashed) {
-            this._documentProcessManager.processCrashed(this._parser.process);
             await this._recoverFromCrashAsync(e);
           } else {
             throw e;
@@ -253,7 +250,6 @@ class DocumentLinter {
       this._document.setDiagnostics(diags);
     } catch (e) {
       if (e instanceof ProcessCrashed) {
-        this._documentProcessManager.processCrashed(this._parser.process);
         await this._recoverFromCrashAsync(e);
       } else {
         throw e;
@@ -295,7 +291,6 @@ class DocumentLinter {
         this._parserPromise = null;
         this._state = DocumentLinterState.NO_PARSER;
         if (e instanceof ProcessCrashed) {
-          this._documentProcessManager.processCrashed(process);
           throw new LintingCrashed(e);
         } else {
           throw e;
@@ -315,24 +310,12 @@ class DocumentProcessManager {
     this._processFactoryPromise = createProcessFactoryAsync();
     this._processesCreated = 0;
     this._processPromise = null;
-    this._process = null;
-  }
-
-  processCrashed(process) {
-    if (!(process instanceof Process)) {
-      throw new TypeError(`Expected Process, but got ${process}`);
-    }
-    if (this._process === process) {
-      this._process = null;
-      this._processPromise = null;
-    }
   }
 
   async createNewProcessAsync() {
     let processFactory = await this._processFactoryPromise;
     let process = await processFactory.createProcessAsync();
     this._processesCreated += 1;
-    this._process = process;
     return process;
   }
 
@@ -341,13 +324,17 @@ class DocumentProcessManager {
     if (this._processPromise === null) {
       this._processPromise = this.createNewProcessAsync();
       // END CRITICAL SECTION (no awaiting above)
+    } else {
+      // END CRITICAL SECTION (no awaiting above)
     }
-    return await this._processPromise;
-  }
-
-  _forgetCurrentProcess() {
-    this._process = null;
-    this._processPromise = null;
+    let process = await this._processPromise;
+    // BEGIN CRITICAL SECTION (no awaiting below)
+    while (process.isTainted()) {
+      this._processPromise = this.createNewProcessAsync();
+      // END CRITICAL SECTION (no awaiting above)
+      process = await this._processPromise;
+    }
+    return process;
   }
 
   // For testing only.
@@ -501,6 +488,10 @@ class Process {
     this._webDemoSetText = wrap("qljs_web_demo_set_text");
   }
 
+  isTainted() {
+    return this._crashedException !== null;
+  }
+
   toString() {
     return `Process(id=${this._idForDebugging})`;
   }

wasm/test-document.js

@@ -626,6 +626,35 @@ describe("DocumentLinter", () => {
 
     assert.strictEqual(documentProcessManager.numberOfProcessesEverCreated, 1);
   });
+
+  it("crashing document does not prevent other document from linting successfully", async () => {
+    let documentProcessManager = new DocumentProcessManager();
+
+    let document1 = new MockDocument("let x; let x;");
+    let linter1 = disposeAfterTest(
+      new DocumentLinter(document1, documentProcessManager)
+    );
+
+    let document2 = new MockDocument("let y; let y;");
+    let linter2 = disposeAfterTest(
+      new DocumentLinter(document2, documentProcessManager)
+    );
+
+    qljs.maybeInjectFault = (_process, functionName) => {
+      if (functionName === "qljs_vscode_lint") {
+        throw new ProcessCrashed("(injected fault)");
+      }
+    };
+    await assert.rejects(async () => {
+      await linter1.editorChangedVisibilityAsync();
+    });
+
+    qljs.maybeInjectFault = originalMaybeInjectFault;
+    await linter2.editorChangedVisibilityAsync();
+    assert.deepStrictEqual(document2.getDiagnosticMessages(), [
+      "redeclaration of variable: y",
+    ]);
+  });
 });
 
 describe("ExhaustiveRNG", () => {