diff --git a/extensions/git/src/diagnostics.ts b/extensions/git/src/diagnostics.ts
index 64bf11076fe08..69ff71b3604cd 100644
--- a/extensions/git/src/diagnostics.ts
+++ b/extensions/git/src/diagnostics.ts
@@ -23,7 +23,8 @@ export class GitCommitInputBoxDiagnosticsManager {
 
 		this.migrateInputValidationSettings()
 			.then(() => {
-				mapEvent(filterEvent(workspace.onDidChangeTextDocument, e => e.document.uri.scheme === 'vscode-scm'), e => e.document)(this.onDidChangeTextDocument, this, this.disposables);
+				mapEvent(filterEvent(workspace.onDidChangeTextDocument, e => e.document.uri.scheme === 'vscode-scm' || e.document.languageId === 'git-commit'), e => e.document)(this.onDidChangeTextDocument, this, this.disposables);
+				filterEvent(workspace.onDidCloseTextDocument, e => e.languageId === 'git-commit')(doc => this.diagnostics.delete(doc.uri), this, this.disposables);
 				filterEvent(workspace.onDidChangeConfiguration, e => e.affectsConfiguration('git.inputValidation') || e.affectsConfiguration('git.inputValidationLength') || e.affectsConfiguration('git.inputValidationSubjectLength'))(this.onDidChangeConfiguration, this, this.disposables);
 			});
 	}
@@ -57,6 +58,11 @@ export class GitCommitInputBoxDiagnosticsManager {
 		for (const repository of this.model.repositories) {
 			this.onDidChangeTextDocument(repository.inputBox.document);
 		}
+		for (const document of workspace.textDocuments) {
+			if (document.languageId === 'git-commit') {
+				this.onDidChangeTextDocument(document);
+			}
+		}
 	}
 
 	private onDidChangeTextDocument(document: TextDocument): void {
@@ -79,10 +85,19 @@ export class GitCommitInputBoxDiagnosticsManager {
 		const diagnostics: Diagnostic[] = [];
 		const inputValidationLength = config.get<number>('inputValidationLength', 50);
 		const inputValidationSubjectLength = config.get<number | undefined>('inputValidationSubjectLength', undefined);
+		const isCommitEditor = document.languageId === 'git-commit';
 
+		let isFirstMessageLine = true;
 		for (let index = 0; index < document.lineCount; index++) {
 			const line = document.lineAt(index);
-			const threshold = index === 0 ? inputValidationSubjectLength ?? inputValidationLength : inputValidationLength;
+
+			// Skip git comment/metadata lines in the commit editor
+			if (isCommitEditor && line.text.startsWith('#')) {
+				continue;
+			}
+
+			const threshold = isFirstMessageLine ? inputValidationSubjectLength ?? inputValidationLength : inputValidationLength;
+			isFirstMessageLine = false;
 
 			if (line.text.length > threshold) {
 				const charactersOver = line.text.length - threshold;
@@ -110,6 +125,7 @@ export class GitCommitInputBoxCodeActionsProvider implements CodeActionProvider
 
 	constructor(private readonly diagnosticsManager: GitCommitInputBoxDiagnosticsManager) {
 		this.disposables.push(languages.registerCodeActionsProvider({ scheme: 'vscode-scm' }, this));
+		this.disposables.push(languages.registerCodeActionsProvider({ language: 'git-commit' }, this));
 	}
 
 	provideCodeActions(document: TextDocument, range: Range | Selection): CodeAction[] {
diff --git a/src/vs/workbench/api/common/extHostTerminalShellIntegration.ts b/src/vs/workbench/api/common/extHostTerminalShellIntegration.ts
index 37a03148780d4..79b306d2a5ad0 100644
--- a/src/vs/workbench/api/common/extHostTerminalShellIntegration.ts
+++ b/src/vs/workbench/api/common/extHostTerminalShellIntegration.ts
@@ -12,7 +12,7 @@ import { IExtHostRpcService } from './extHostRpcService.js';
 import { IExtHostTerminalService } from './extHostTerminalService.js';
 import { Emitter, type Event } from '../../../base/common/event.js';
 import { URI } from '../../../base/common/uri.js';
-import { AsyncIterableObject, Barrier, type AsyncIterableEmitter } from '../../../base/common/async.js';
+import { AsyncIterableProducer, Barrier, DeferredPromise, type AsyncIterableEmitter } from '../../../base/common/async.js';
 
 export interface IExtHostTerminalShellIntegration extends ExtHostTerminalShellIntegrationShape {
 	readonly _serviceBrand: undefined;
@@ -400,7 +400,7 @@ class InternalTerminalShellExecution {
 	private _createDataStream(): AsyncIterable<string> {
 		if (!this._dataStream) {
 			if (this._isEnded) {
-				return AsyncIterableObject.EMPTY;
+				return AsyncIterableProducer.EMPTY;
 			}
 			this._dataStream = new ShellExecutionDataStream();
 		}
@@ -432,7 +432,7 @@ class InternalTerminalShellExecution {
 
 class ShellExecutionDataStream extends Disposable {
 	private _barrier: Barrier | undefined;
-	private _iterables: AsyncIterableObject<string>[] = [];
+	private _completionPromises: DeferredPromise<void>[] = [];
 	private _emitters: AsyncIterableEmitter<string>[] = [];
 
 	createIterable(): AsyncIterable<string> {
@@ -440,11 +440,13 @@ class ShellExecutionDataStream extends Disposable {
 			this._barrier = new Barrier();
 		}
 		const barrier = this._barrier;
-		const iterable = new AsyncIterableObject<string>(async emitter => {
+		const completionPromise = new DeferredPromise<void>();
+		this._completionPromises.push(completionPromise);
+		const iterable = new AsyncIterableProducer<string>(async emitter => {
 			this._emitters.push(emitter);
 			await barrier.wait();
+			completionPromise.complete(undefined);
 		});
-		this._iterables.push(iterable);
 		return iterable;
 	}
 
@@ -459,7 +461,7 @@ class ShellExecutionDataStream extends Disposable {
 	}
 
 	async flush(): Promise<void> {
-		await Promise.all(this._iterables.map(e => e.toPromise()));
+		await Promise.all(this._completionPromises.map(p => p.p));
 	}
 }
 
diff --git a/src/vs/workbench/api/test/common/extHostTerminalShellIntegration.test.ts b/src/vs/workbench/api/test/common/extHostTerminalShellIntegration.test.ts
index 23e544f1568f6..7fb813a6f76ba 100644
--- a/src/vs/workbench/api/test/common/extHostTerminalShellIntegration.test.ts
+++ b/src/vs/workbench/api/test/common/extHostTerminalShellIntegration.test.ts
@@ -64,7 +64,7 @@ suite('InternalTerminalShellIntegration', () => {
 	}
 
 	async function emitData(data: string): Promise<void> {
-		// AsyncIterableObjects are initialized in a microtask, this doesn't matter in practice
+		// AsyncIterableProducers are initialized in a microtask, this doesn't matter in practice
 		// since the events will always come through in different events.
 		await new Promise<void>(r => queueMicrotask(r));
 		si.emitData(data);