Reduce unnecessary churn when generating LocalPackages config (#20574)

* reduce churn adding LocalPackage by not updating mapping in existing tasks w/o version bump

* Only update package.json, package-lock.json, npm-shrinkwrap.json under _buildsConfigs if they already exist to avoid unnecessary source churn.  (they only need to be synced if the config has different dependencies)

* bump for testing

* fix

* format

* clean up

* Revert "bump for testing"

This reverts commit 0e12ae4.

Author: merlynomsft

BuildConfigGen/Program.cs

@@ -594,6 +594,8 @@ private static void MainUpdateTask(
                             // Note: CheckTaskInputContainsPreprocessorInstructions is expensive, so only call if needed
                             if (versionUpdated || taskConfigExists || HasTaskInputContainsPreprocessorInstructions(gitRootPath, taskTargetPath, config) || config.isNode)
                             {
+                                var existingLocalPackageVersion = ReadTaskJsonIfExists(taskOutput, "task.json");
+
                                 CopyConfig(gitRootPath, taskTargetPath, taskOutput, skipPathName: buildConfigs, skipFileName: null, removeExtraFiles: true, throwIfNotUpdatingFileForApplyingOverridesAndPreProcessor: false, config: config, allowPreprocessorDirectives: true);
 
                                 if (config.enableBuildConfigOverrides)
@@ -609,8 +611,8 @@ private static void MainUpdateTask(
 
                                 WriteWIFInputTaskJson(taskOutput, config, "task.json", isLoc: false);
                                 WriteWIFInputTaskJson(taskOutput, config, "task.loc.json", isLoc: true);
-                                WriteTaskJson(taskOutput, taskVersionState.configTaskVersionMapping, config, "task.json");
-                                WriteTaskJson(taskOutput, taskVersionState.configTaskVersionMapping, config, "task.loc.json");
+                                WriteTaskJson(taskOutput, taskVersionState, config, "task.json", existingLocalPackageVersion);
+                                WriteTaskJson(taskOutput, taskVersionState, config, "task.loc.json", existingLocalPackageVersion);
                             }
 
                             WriteInputTaskJson(taskTargetPath, taskVersionState.configTaskVersionMapping, "task.json");
@@ -907,21 +909,54 @@ private static void PreprocessIfExtensionEnabledInConfig(string file, Config.Con
             }
         }
 
+        private static string? ReadTaskJsonIfExists(string taskPath, string fileName)
+        {
+            string outputTaskPath = Path.Combine(taskPath, fileName);
+            if(!File.Exists(outputTaskPath))
+            {
+                return null;
+            }
+
+            JsonNode outputTaskNode = JsonNode.Parse(ensureUpdateModeVerifier!.FileReadAllText(outputTaskPath))!;
+            var outputTaskNodeObject = outputTaskNode.AsObject();
+
+            // get LocalPackage version from _buildConfigMapping in outputTaskNodeObject (if one exists)
+            return outputTaskNodeObject["_buildConfigMapping"]?.AsObject()?[Config.LocalPackages.constMappingKey]?.GetValue<string>();
+        }
 
-        private static void WriteTaskJson(string taskPath, Dictionary<Config.ConfigRecord, TaskVersion> configTaskVersionMapping, Config.ConfigRecord config, string fileName)
+        private static void WriteTaskJson(string taskPath, TaskStateStruct taskState, Config.ConfigRecord config, string fileName, string? existingLocalPackageVersion)
         {
             string outputTaskPath = Path.Combine(taskPath, fileName);
             JsonNode outputTaskNode = JsonNode.Parse(ensureUpdateModeVerifier!.FileReadAllText(outputTaskPath))!;
-            outputTaskNode["version"]!["Major"] = configTaskVersionMapping[config].Major;
-            outputTaskNode["version"]!["Minor"] = configTaskVersionMapping[config].Minor;
-            outputTaskNode["version"]!["Patch"] = configTaskVersionMapping[config].Patch;
-            outputTaskNode.AsObject()?.Remove("_buildConfigMapping");
+
+            outputTaskNode["version"]!["Major"] = taskState.configTaskVersionMapping[config].Major;
+            outputTaskNode["version"]!["Minor"] = taskState.configTaskVersionMapping[config].Minor;
+            outputTaskNode["version"]!["Patch"] = taskState.configTaskVersionMapping[config].Patch;
+
+            var outputTaskNodeObject = outputTaskNode.AsObject();
+            outputTaskNodeObject.Remove("_buildConfigMapping");
+
+            bool anyVersionsUpdatedExceptForGlobal = taskState.versionsUpdated.Where(x => !x.useGlobalVersion).Any();
 
             JsonObject configMapping = new JsonObject();
-            var configTaskVersionMappingSortedByConfig = configTaskVersionMapping.OrderBy(x => x.Key.name);
+            var configTaskVersionMappingSortedByConfig = taskState.configTaskVersionMapping.OrderBy(x => x.Key.name);
             foreach (var cfg in configTaskVersionMappingSortedByConfig)
             {
-                configMapping.Add(new(cfg.Key.constMappingKey, cfg.Value.ToString()));
+                if (!config.useGlobalVersion && cfg.Key.useGlobalVersion && !anyVersionsUpdatedExceptForGlobal)
+                {
+                    // To minimize noise in version control when adding the globalVersion,
+                    // unless the config being generated is the globalVersion (written to _generated_local),
+                    // if no other versions are updated other than the globalVersion,
+                    // don't change the global version in the existing generated file.
+                    if (existingLocalPackageVersion != null)
+                    {
+                        configMapping.Add(new(cfg.Key.constMappingKey, existingLocalPackageVersion));
+                    }
+                }
+                else
+                {
+                    configMapping.Add(new(cfg.Key.constMappingKey, cfg.Value.ToString()));
+                }
             }
 
             outputTaskNode.AsObject().Add("_buildConfigMapping", configMapping);

make-util.js

@@ -1947,19 +1947,23 @@ function syncGeneratedFilesWrapper(originalFunction, basicGenTaskPath, basicGenT
         copyCandidates.forEach((candidatePath) => {
             const relativePath = path.relative(genTaskPath, candidatePath);
             let dest = path.join(__dirname, 'Tasks', baseTaskName, relativePath);
-
+            
             if (config) {  
                 dest = path.join(__dirname, 'Tasks', baseTaskName, '_buildConfigs', config, relativePath);
             }
 
-            const folderPath = path.dirname(dest);
-            if (!fs.existsSync(folderPath)) {
-                console.log(`Creating folder ${folderPath}`);
-                shell.mkdir('-p', folderPath);
-            }
+            // only update Tasks/[task]/_buildConfigs/[configs]/package.json, etc if it already exists
+            if(fs.existsSync(dest))
+            {
+                const folderPath = path.dirname(dest);
+                if (!fs.existsSync(folderPath)) {
+                    console.log(`Creating folder ${folderPath}`);
+                    shell.mkdir('-p', folderPath);
+                }
 
-            console.log(`Copying ${candidatePath} to ${dest}`);
-            fs.copyFileSync(candidatePath, dest);
+                console.log(`Copying ${candidatePath} to ${dest}`);
+                fs.copyFileSync(candidatePath, dest);
+            }
         });
     }
 }