convert git merge into git cmd

src/commands/git/merge.ts

@@ -4,10 +4,12 @@ import type { GitLog } from '../../git/models/log';
 import type { GitReference } from '../../git/models/reference';
 import { createRevisionRange, getReferenceLabel, isRevisionReference } from '../../git/models/reference';
 import type { Repository } from '../../git/models/repository';
+import { showGenericErrorMessage } from '../../messages';
 import type { DirectiveQuickPickItem } from '../../quickpicks/items/directive';
 import { createDirectiveQuickPickItem, Directive } from '../../quickpicks/items/directive';
 import type { FlagsQuickPickItem } from '../../quickpicks/items/flags';
 import { createFlagsQuickPickItem } from '../../quickpicks/items/flags';
+import { Logger } from '../../system/logger';
 import { pluralize } from '../../system/string';
 import type { ViewsWithRepositoryFolders } from '../../views/viewBase';
 import type {
@@ -76,8 +78,13 @@ export class MergeGitCommand extends QuickCommand<State> {
 		return false;
 	}
 
-	execute(state: MergeStepState) {
-		state.repo.merge(...state.flags, state.reference.ref);
+	async execute(state: MergeStepState) {
+		try {
+			await state.repo.git.merge(state.reference.ref, state.flags);
+		} catch (ex) {
+			Logger.error(ex, this.title);
+			void showGenericErrorMessage(ex);
+		}
 	}
 
 	protected async *steps(state: PartialStepState<State>): StepGenerator {
@@ -200,7 +207,7 @@ export class MergeGitCommand extends QuickCommand<State> {
 			state.flags = result;
 
 			endSteps(state);
-			this.execute(state as MergeStepState);
+			await this.execute(state as MergeStepState);
 		}
 
 		return state.counter < 0 ? StepResultBreak : undefined;

src/commands/git/switch.ts

@@ -104,7 +104,7 @@ export class SwitchGitCommand extends QuickCommand<State> {
 		);
 
 		if (state.fastForwardTo != null) {
-			state.repos[0].merge('--ff-only', state.fastForwardTo.ref);
+			await state.repos[0].git.merge(state.fastForwardTo.ref, ['--ff-only']);
 		}
 	}
 
@@ -211,7 +211,7 @@ export class SwitchGitCommand extends QuickCommand<State> {
 				);
 				if (worktree != null && !worktree.isDefault) {
 					if (state.fastForwardTo != null) {
-						state.repos[0].merge('--ff-only', state.fastForwardTo.ref);
+						await state.repos[0].git.merge(state.fastForwardTo.ref, ['--ff-only']);
 					}
 
 					const worktreeResult = yield* getSteps(

src/env/node/git/git.ts

@@ -173,6 +173,12 @@ const tagErrorAndReason: [RegExp, TagErrorReason][] = [
 	[GitErrors.remoteRejected, TagErrorReason.RemoteRejected],
 ];
 
+const mergeErrorAndReason: [RegExp, MergeErrorReason][] = [
+	[GitErrors.conflict, MergeErrorReason.Conflict],
+	[GitErrors.unmergedFiles, MergeErrorReason.UnmergedFiles],
+	[GitErrors.unstagedChanges, MergeErrorReason.UnstagedChanges],
+];
+
 export class Git {
 	/** Map of running git commands -- avoids running duplicate overlaping commands */
 	private readonly pendingCommands = new Map<string, Promise<string | Buffer>>();
@@ -1092,6 +1098,21 @@ export class Git {
 		}
 	}
 
+	async merge(repoPath: string, args: string[]) {
+		try {
+			await this.git<string>({ cwd: repoPath }, 'merge', ...args);
+		} catch (ex) {
+			const msg: string = ex?.toString() ?? '';
+			for (const [error, reason] of mergeErrorAndReason) {
+				if (error.test(msg) || error.test(ex.stderr ?? '')) {
+					throw new MergeError(reason, ex);
+				}
+			}
+
+			throw new MergeError(MergeErrorReason.Other, ex);
+		}
+	}
+
 	for_each_ref__branch(repoPath: string, options: { all: boolean } = { all: false }) {
 		const params = ['for-each-ref', `--format=${parseGitBranchesDefaultFormat}`, 'refs/heads'];
 		if (options.all) {

src/env/node/git/localGitProvider.ts

@@ -1076,6 +1076,32 @@ export class LocalGitProvider implements GitProvider, Disposable {
 		this.container.events.fire('git:cache:reset', { repoPath: repoPath, caches: ['remotes'] });
 	}
 
+	@log()
+	async merge(
+		repoPath: string,
+		ref: string,
+		options?: { fastForwardOnly?: boolean; noFastForward?: boolean; noCommit?: boolean; squash?: boolean },
+	): Promise<void> {
+		const args: string[] = [];
+		if (options?.fastForwardOnly) {
+			args.push('--ff-only');
+		} else if (options?.noFastForward) {
+			args.push('--no-ff');
+		}
+
+		if (options?.noCommit) {
+			args.push('--no-commit');
+		}
+
+		if (options?.squash) {
+			args.push('--squash');
+		}
+
+		args.push(ref);
+
+		await this.git.merge(repoPath, args);
+	}
+
 	@log()
 	async applyChangesToWorkingFile(uri: GitUri, ref1?: string, ref2?: string) {
 		const scope = getLogScope();

src/git/errors.ts

@@ -567,3 +567,70 @@ export class TagError extends Error {
 		return this;
 	}
 }
+
+export const enum MergeErrorReason {
+	Conflict,
+	UnmergedFiles,
+	UnstagedChanges,
+	Other,
+}
+
+export class MergeError extends Error {
+	static is(ex: unknown, reason?: MergeErrorReason): ex is MergeError {
+		return ex instanceof MergeError && (reason == null || ex.reason === reason);
+	}
+
+	readonly original?: Error;
+	readonly reason: MergeErrorReason | undefined;
+	ref?: string;
+
+	private static buildMergeErrorMessage(reason?: MergeErrorReason, ref?: string): string {
+		let baseMessage: string;
+		if (ref != null) {
+			baseMessage = `Unable to merge ${ref}`;
+		} else {
+			baseMessage = `Unable to merge`;
+		}
+
+		switch (reason) {
+			case MergeErrorReason.Conflict:
+				return `${baseMessage} due to conflicts`;
+			case MergeErrorReason.UnmergedFiles:
+				return `${baseMessage} because you have unmerged files`;
+			case MergeErrorReason.UnstagedChanges:
+				return `${baseMessage} because you have unstaged changes`;
+			default:
+				return baseMessage;
+		}
+
+		return baseMessage;
+	}
+
+	constructor(reason?: MergeErrorReason, original?: Error, ref?: string);
+	constructor(message?: string, original?: Error);
+	constructor(messageOrReason: string | MergeErrorReason | undefined, original?: Error, ref?: string) {
+		let reason: MergeErrorReason | undefined;
+		if (typeof messageOrReason !== 'string') {
+			reason = messageOrReason as MergeErrorReason;
+		} else {
+			super(messageOrReason);
+		}
+
+		const message =
+			typeof messageOrReason === 'string'
+				? messageOrReason
+				: MergeError.buildMergeErrorMessage(messageOrReason as MergeErrorReason, ref);
+		super(message);
+
+		this.original = original;
+		this.reason = reason;
+		this.ref = ref;
+		Error.captureStackTrace?.(this, MergeError);
+	}
+
+	WithRef(ref: string) {
+		this.ref = ref;
+		this.message = MergeError.buildMergeErrorMessage(this.reason, ref);
+		return this;
+	}
+}

src/git/gitProvider.ts

@@ -125,6 +125,11 @@ export interface GitProviderRepository {
 	addRemote?(repoPath: string, name: string, url: string, options?: { fetch?: boolean }): Promise<void>;
 	pruneRemote?(repoPath: string, name: string): Promise<void>;
 	removeRemote?(repoPath: string, name: string): Promise<void>;
+	merge?(
+		repoPath: string,
+		ref: string,
+		options?: { fastForwardOnly?: boolean; noFastForward?: boolean; noCommit?: boolean; squash?: boolean },
+	): Promise<void>;
 
 	applyUnreachableCommitForPatch?(
 		repoPath: string,

src/git/gitProviderService.ts

@@ -1334,6 +1334,32 @@ export class GitProviderService implements Disposable {
 		return provider.removeRemote(path, name);
 	}
 
+	@log()
+	merge(repoPath: string, ref: string, flags: string[] | undefined = []): Promise<void> {
+		const { provider, path } = this.getProvider(repoPath);
+		if (provider.merge == null) throw new ProviderNotSupportedError(provider.descriptor.name);
+		const options: { fastForwardOnly?: boolean; noFastForward?: boolean; noCommit?: boolean; squash?: boolean } =
+			{};
+		for (const flag of flags) {
+			switch (flag) {
+				case '--ff-only':
+					options.fastForwardOnly = true;
+					break;
+				case '--no-ff':
+					options.noFastForward = true;
+					break;
+				case '--squash':
+					options.squash = true;
+					break;
+				case '--no-commit':
+					options.noCommit = true;
+					break;
+			}
+		}
+
+		return provider.merge(path, ref, options);
+	}
+
 	@log()
 	applyChangesToWorkingFile(uri: GitUri, ref1?: string, ref2?: string): Promise<void> {
 		const { provider } = this.getProvider(uri);

src/git/models/repository.ts

@@ -733,11 +733,6 @@ export class Repository implements Disposable {
 		return this.git.getWorktree(w => w.uri.toString() === url);
 	}
 
-	@log()
-	merge(...args: string[]) {
-		void this.runTerminalCommand('merge', ...args);
-	}
-
 	@gate()
 	@log()
 	async pull(options?: { progress?: boolean; rebase?: boolean }) {