introduce --merge to bring up merge editor (for microsoft#5770) (microsoft#155039)

* introduce `--merge` to bring up merge editor (for microsoft#5770)

* wait on proper editor when merging

* sqlite slowness

* disable flush on write in tests unless disk tests

* more runWithFakedTimers

* disable flush also in pfs

* introduce `IResourceMergeEditorInput`

* cleanup

* align with merge editor names

* stronger check

* adopt `ResourceSet`

* no need to coalesce

* improve `matches` method

Author: bpasero

src/vs/code/electron-main/app.ts

@@ -1012,6 +1012,7 @@ export class CodeApplication extends Disposable {
 			cli: args,
 			forceNewWindow: args['new-window'] || (!hasCliArgs && args['unity-launch']),
 			diffMode: args.diff,
+			mergeMode: args.merge,
 			noRecentEntry,
 			waitMarkerFileURI,
 			gotoLineMode: args.goto,

src/vs/platform/environment/common/argv.ts

@@ -18,6 +18,7 @@ export interface NativeParsedArgs {
 	wait?: boolean;
 	waitMarkerFilePath?: string;
 	diff?: boolean;
+	merge?: boolean;
 	add?: boolean;
 	goto?: boolean;
 	'new-window'?: boolean;

src/vs/platform/environment/node/argv.ts

@@ -41,6 +41,7 @@ type OptionTypeName<T> =
 
 export const OPTIONS: OptionDescriptions<Required<NativeParsedArgs>> = {
 	'diff': { type: 'boolean', cat: 'o', alias: 'd', args: ['file', 'file'], description: localize('diff', "Compare two files with each other.") },
+	'merge': { type: 'boolean', cat: 'o', alias: 'm', args: ['path1', 'path2', 'base', 'result'], description: localize('merge', "Perform a three-way merge by providing paths for two modified versions of a file, the common origin of both modified versions and the output file to save merge results.") },
 	'add': { type: 'boolean', cat: 'o', alias: 'a', args: 'folder', description: localize('add', "Add folder(s) to the last active window.") },
 	'goto': { type: 'boolean', cat: 'o', alias: 'g', args: 'file:line[:character]', description: localize('goto', "Open a file at the path on the specified line and character position.") },
 	'new-window': { type: 'boolean', cat: 'o', alias: 'n', description: localize('newWindow', "Force to open a new window.") },

src/vs/platform/launch/electron-main/launchMainService.ts

@@ -190,6 +190,7 @@ export class LaunchMainService implements ILaunchMainService {
 				preferNewWindow: !args['reuse-window'] && !args.wait,
 				forceReuseWindow: args['reuse-window'],
 				diffMode: args.diff,
+				mergeMode: args.merge,
 				addMode: args.add,
 				noRecentEntry: !!args['skip-add-to-recently-opened'],
 				gotoLineMode: args.goto

src/vs/platform/native/electron-main/nativeHostMainService.ts

@@ -154,6 +154,7 @@ export class NativeHostMainService extends Disposable implements INativeHostMain
 				forceReuseWindow: options.forceReuseWindow,
 				preferNewWindow: options.preferNewWindow,
 				diffMode: options.diffMode,
+				mergeMode: options.mergeMode,
 				addMode: options.addMode,
 				gotoLineMode: options.gotoLineMode,
 				noRecentEntry: options.noRecentEntry,

src/vs/platform/window/common/window.ts

@@ -52,6 +52,7 @@ export interface IOpenWindowOptions extends IBaseOpenWindowsOptions {
 	readonly addMode?: boolean;
 
 	readonly diffMode?: boolean;
+	readonly mergeMode?: boolean;
 	readonly gotoLineMode?: boolean;
 
 	readonly waitMarkerFileURI?: URI;
@@ -240,6 +241,7 @@ interface IPathsToWaitForData {
 export interface IOpenFileRequest {
 	readonly filesToOpenOrCreate?: IPathData[];
 	readonly filesToDiff?: IPathData[];
+	readonly filesToMerge?: IPathData[];
 }
 
 /**
@@ -270,6 +272,7 @@ export interface IWindowConfiguration {
 
 	filesToOpenOrCreate?: IPath[];
 	filesToDiff?: IPath[];
+	filesToMerge?: IPath[];
 }
 
 export interface IOSConfiguration {

src/vs/platform/windows/electron-main/window.ts

@@ -899,6 +899,7 @@ export class CodeWindow extends Disposable implements ICodeWindow {
 		// Delete some properties we do not want during reload
 		delete configuration.filesToOpenOrCreate;
 		delete configuration.filesToDiff;
+		delete configuration.filesToMerge;
 		delete configuration.filesToWait;
 
 		// Some configuration things get inherited if the window is being reloaded and we are

src/vs/platform/windows/electron-main/windows.ts

@@ -85,6 +85,7 @@ export interface IOpenConfiguration extends IBaseOpenConfiguration {
 	readonly forceReuseWindow?: boolean;
 	readonly forceEmpty?: boolean;
 	readonly diffMode?: boolean;
+	readonly mergeMode?: boolean;
 	addMode?: boolean;
 	readonly gotoLineMode?: boolean;
 	readonly initialStartup?: boolean;

src/vs/platform/windows/electron-main/windowsMainService.ts

@@ -118,6 +118,8 @@ interface IFilesToOpen {
 
 	filesToOpenOrCreate: IPath[];
 	filesToDiff: IPath[];
+	filesToMerge: IPath[];
+
 	filesToWait?: IPathsToWaitFor;
 }
 
@@ -296,7 +298,7 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 				workspacesToOpen.push(path);
 			} else if (path.fileUri) {
 				if (!filesToOpen) {
-					filesToOpen = { filesToOpenOrCreate: [], filesToDiff: [], remoteAuthority: path.remoteAuthority };
+					filesToOpen = { filesToOpenOrCreate: [], filesToDiff: [], filesToMerge: [], remoteAuthority: path.remoteAuthority };
 				}
 				filesToOpen.filesToOpenOrCreate.push(path);
 			} else if (path.backupPath) {
@@ -312,9 +314,16 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 			filesToOpen.filesToOpenOrCreate = [];
 		}
 
+		// When run with --merge, take the first 4 files to open as files to merge
+		if (openConfig.mergeMode && filesToOpen && filesToOpen.filesToOpenOrCreate.length === 4) {
+			filesToOpen.filesToMerge = filesToOpen.filesToOpenOrCreate.slice(0, 4);
+			filesToOpen.filesToOpenOrCreate = [];
+			filesToOpen.filesToDiff = [];
+		}
+
 		// When run with --wait, make sure we keep the paths to wait for
 		if (filesToOpen && openConfig.waitMarkerFileURI) {
-			filesToOpen.filesToWait = { paths: [...filesToOpen.filesToDiff, ...filesToOpen.filesToOpenOrCreate], waitMarkerFileUri: openConfig.waitMarkerFileURI };
+			filesToOpen.filesToWait = { paths: [...filesToOpen.filesToDiff, filesToOpen.filesToMerge[3] /* [3] is the resulting merge file */, ...filesToOpen.filesToOpenOrCreate], waitMarkerFileUri: openConfig.waitMarkerFileURI };
 		}
 
 		// These are windows to restore because of hot-exit or from previous session (only performed once on startup!)
@@ -384,9 +393,10 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 		}
 
 		// Remember in recent document list (unless this opens for extension development)
-		// Also do not add paths when files are opened for diffing, only if opened individually
+		// Also do not add paths when files are opened for diffing or merging, only if opened individually
 		const isDiff = filesToOpen && filesToOpen.filesToDiff.length > 0;
-		if (!usedWindows.some(window => window.isExtensionDevelopmentHost) && !isDiff && !openConfig.noRecentEntry) {
+		const isMerge = filesToOpen && filesToOpen.filesToMerge.length > 0;
+		if (!usedWindows.some(window => window.isExtensionDevelopmentHost) && !isDiff && !isMerge && !openConfig.noRecentEntry) {
 			const recents: IRecent[] = [];
 			for (const pathToOpen of pathsToOpen) {
 				if (isWorkspacePathToOpen(pathToOpen) && !pathToOpen.transient /* never add transient workspaces to history */) {
@@ -461,13 +471,13 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 			}
 		}
 
-		// Handle files to open/diff or to create when we dont open a folder and we do not restore any
+		// Handle files to open/diff/merge or to create when we dont open a folder and we do not restore any
 		// folder/untitled from hot-exit by trying to open them in the window that fits best
 		const potentialNewWindowsCount = foldersToOpen.length + workspacesToOpen.length + emptyToRestore.length;
 		if (filesToOpen && potentialNewWindowsCount === 0) {
 
 			// Find suitable window or folder path to open files in
-			const fileToCheck = filesToOpen.filesToOpenOrCreate[0] || filesToOpen.filesToDiff[0];
+			const fileToCheck = filesToOpen.filesToOpenOrCreate[0] || filesToOpen.filesToDiff[0] || filesToOpen.filesToMerge[3] /* [3] is the resulting merge file */;
 
 			// only look at the windows with correct authority
 			const windows = this.getWindows().filter(window => filesToOpen && isEqualAuthority(window.remoteAuthority, filesToOpen.remoteAuthority));
@@ -625,6 +635,7 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 		const params: INativeOpenFileRequest = {
 			filesToOpenOrCreate: filesToOpen?.filesToOpenOrCreate,
 			filesToDiff: filesToOpen?.filesToDiff,
+			filesToMerge: filesToOpen?.filesToMerge,
 			filesToWait: filesToOpen?.filesToWait,
 			termProgram: configuration?.userEnv?.['TERM_PROGRAM']
 		};
@@ -792,7 +803,12 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 			ignoreFileNotFound: true,
 			gotoLineMode: cli.goto,
 			remoteAuthority: cli.remote || undefined,
-			forceOpenWorkspaceAsFile: cli.diff && cli._.length === 2 // special case diff mode to force open workspace as file (https://github.com/microsoft/vscode/issues/149731)
+			forceOpenWorkspaceAsFile:
+				// special case diff / merge mode to force open
+				// workspace as file
+				// https://github.com/microsoft/vscode/issues/149731
+				cli.diff && cli._.length === 2 ||
+				cli.merge && cli._.length === 4
 		};
 
 		// folder uris
@@ -1323,6 +1339,7 @@ export class WindowsMainService extends Disposable implements IWindowsMainServic
 
 			filesToOpenOrCreate: options.filesToOpen?.filesToOpenOrCreate,
 			filesToDiff: options.filesToOpen?.filesToDiff,
+			filesToMerge: options.filesToOpen?.filesToMerge,
 			filesToWait: options.filesToOpen?.filesToWait,
 
 			logLevel: this.logService.getLevel(),

src/vs/server/node/server.cli.ts

@@ -59,6 +59,7 @@ const isSupportedForPipe = (optionId: keyof RemoteParsedArgs) => {
 		case 'file-uri':
 		case 'add':
 		case 'diff':
+		case 'merge':
 		case 'wait':
 		case 'goto':
 		case 'reuse-window':
@@ -297,6 +298,7 @@ export function main(desc: ProductDescription, args: string[]): void {
 			fileURIs,
 			folderURIs,
 			diffMode: parsedArgs.diff,
+			mergeMode: parsedArgs.merge,
 			addMode: parsedArgs.add,
 			gotoLineMode: parsedArgs.goto,
 			forceReuseWindow: parsedArgs['reuse-window'],