From 3dfa75e60d0af5d329f96703741a13d680e1ac89 Mon Sep 17 00:00:00 2001
From: Tobias Koppers <tobias.koppers@googlemail.com>
Date: Fri, 7 Jul 2017 12:51:55 +0200
Subject: [PATCH] generate source map names globally

---
 lib/SourceMapDevToolPlugin.js | 64 +++++++++++++++++++++++------------
 1 file changed, 42 insertions(+), 22 deletions(-)

diff --git a/lib/SourceMapDevToolPlugin.js b/lib/SourceMapDevToolPlugin.js
index 2aec14de0dc..5f001b60dd8 100644
--- a/lib/SourceMapDevToolPlugin.js
+++ b/lib/SourceMapDevToolPlugin.js
@@ -46,8 +46,7 @@ class SourceMapDevToolPlugin {
 		compiler.plugin("compilation", compilation => {
 			new SourceMapDevToolModuleOptionsPlugin(options).apply(compilation);
 			compilation.plugin("after-optimize-chunk-assets", function(chunks) {
-				let allModules = [];
-				let allModuleFilenames = [];
+				const moduleToSourceNameMapping = new Map();
 				const tasks = [];
 				chunks.forEach(function(chunk) {
 					chunk.files.filter(ModuleFilenameHelpers.matchObject.bind(undefined, options)).map(function(file) {
@@ -84,40 +83,61 @@ class SourceMapDevToolPlugin {
 							const module = compilation.findModule(source);
 							return module || source;
 						});
-						const moduleFilenames = modules.map(module => ModuleFilenameHelpers.createFilename(module, moduleFilenameTemplate, requestShortener));
+						for(const module of modules) {
+							if(!moduleToSourceNameMapping.get(module)) {
+								moduleToSourceNameMapping.set(module, ModuleFilenameHelpers.createFilename(module, moduleFilenameTemplate, requestShortener));
+							}
+						}
 						task.modules = modules;
-						task.moduleFilenames = moduleFilenames;
 						return task;
 					}).forEach(task => {
-						allModules = allModules.concat(task.modules);
-						allModuleFilenames = allModuleFilenames.concat(task.moduleFilenames);
 						tasks.push(task);
 					});
 				});
-				allModuleFilenames = ModuleFilenameHelpers.replaceDuplicates(allModuleFilenames, (filename, i) => ModuleFilenameHelpers.createFilename(allModules[i], fallbackModuleFilenameTemplate, requestShortener), (ai, bi) => {
-					let a = allModules[ai];
-					let b = allModules[bi];
-					a = !a ? "" : typeof a === "string" ? a : a.identifier();
-					b = !b ? "" : typeof b === "string" ? b : b.identifier();
-					return a.length - b.length;
-				});
-				allModuleFilenames = ModuleFilenameHelpers.replaceDuplicates(allModuleFilenames, (filename, i, n) => {
-					for(let j = 0; j < n; j++)
-						filename += "*";
-					return filename;
-				});
-				tasks.forEach(task => {
-					task.moduleFilenames = allModuleFilenames.slice(0, task.moduleFilenames.length);
-					allModuleFilenames = allModuleFilenames.slice(task.moduleFilenames.length);
+				const usedNamesSet = new Set(moduleToSourceNameMapping.values());
+				const conflictDetectionSet = new Set();
+
+				// all modules in defined order (longest identifier first)
+				const allModules = Array.from(moduleToSourceNameMapping.keys()).sort((a, b) => {
+					const ai = typeof a === "string" ? a : a.identifier();
+					const bi = typeof b === "string" ? b : b.identifier();
+					return ai.length - bi.length;
 				});
+
+				// find modules with conflicting source names
+				for(const module of allModules) {
+					let sourceName = moduleToSourceNameMapping.get(module);
+					let hasName = conflictDetectionSet.has(sourceName);
+					if(!hasName) {
+						conflictDetectionSet.add(sourceName);
+						continue;
+					}
+
+					// try the fallback name first
+					sourceName = ModuleFilenameHelpers.createFilename(module, fallbackModuleFilenameTemplate, requestShortener);
+					hasName = usedNamesSet.has(sourceName);
+					if(!hasName) {
+						moduleToSourceNameMapping.set(module, sourceName);
+						usedNamesSet.add(sourceName);
+						continue;
+					}
+
+					// elsewise just append stars until we have a valid name
+					do {
+						sourceName += "*";
+						hasName = usedNamesSet.has(sourceName);
+					} while(hasName);
+					moduleToSourceNameMapping.set(module, sourceName);
+					usedNamesSet.add(sourceName);
+				}
 				tasks.forEach(function(task) {
 					const chunk = task.chunk;
 					const file = task.file;
 					const asset = task.asset;
 					const sourceMap = task.sourceMap;
 					const source = task.source;
-					const moduleFilenames = task.moduleFilenames;
 					const modules = task.modules;
+					const moduleFilenames = modules.map(m => moduleToSourceNameMapping.get(m));
 					sourceMap.sources = moduleFilenames;
 					if(sourceMap.sourcesContent && !options.noSources) {
 						sourceMap.sourcesContent = sourceMap.sourcesContent.map((content, i) => `${content}\n\n\n${ModuleFilenameHelpers.createFooter(modules[i], requestShortener)}`);