Fix thread safety issue in FindAppHostProjectFilesAsync by switching to ConcurrentBag (#9655)

Copilot · radical · mitchdenny · web-flow · commit f68e13b5ef81 · 2025-06-11T14:49:58.000+10:00
* Initial plan for issue

* Fix thread safety issue in FindAppHostProjectFilesAsync using ConcurrentBag

Co-authored-by: radical &lt;1472+radical@users.noreply.github.com&gt;

* Remove debugging output line as requested in code review

Co-authored-by: radical &lt;1472+radical@users.noreply.github.com&gt;

* Revert test file changes as requested in code review

Co-authored-by: radical &lt;1472+radical@users.noreply.github.com&gt;

* Switch from ConcurrentBag to List with locking as requested in code review

Co-authored-by: mitchdenny &lt;513398+mitchdenny@users.noreply.github.com&gt;

---------

Co-authored-by: copilot-swe-agent[bot] &lt;198982749+Copilot@users.noreply.github.com&gt;
Co-authored-by: radical &lt;1472+radical@users.noreply.github.com&gt;
Co-authored-by: mitchdenny &lt;513398+mitchdenny@users.noreply.github.com&gt;
diff --git a/src/Aspire.Cli/Projects/ProjectLocator.cs b/src/Aspire.Cli/Projects/ProjectLocator.cs
@@ -25,6 +25,7 @@ private async Task<List<FileInfo>> FindAppHostProjectFilesAsync(DirectoryInfo se
         return await interactionService.ShowStatusAsync("Searching", async () =>
         {
             var appHostProjects = new List<FileInfo>();
+            var lockObject = new object();
             logger.LogDebug("Searching for project files in {SearchDirectory}", searchDirectory.FullName);
             var enumerationOptions = new EnumerationOptions
             {
@@ -52,7 +53,10 @@ await Parallel.ForEachAsync(projectFiles, async (projectFile, ct) =>
                     logger.LogDebug("Found AppHost project file {ProjectFile} in {SearchDirectory}", projectFile.FullName, searchDirectory.FullName);
                     var relativePath = Path.GetRelativePath(currentDirectory.FullName, projectFile.FullName);
                     interactionService.DisplaySubtleMessage(relativePath);
-                    appHostProjects.Add(projectFile);
+                    lock (lockObject)
+                    {
+                        appHostProjects.Add(projectFile);
+                    }
                 }
                 else
                 {

Original file line number	Diff line number	Diff line change
`@@ -25,6 +25,7 @@ private async Task<List<FileInfo>> FindAppHostProjectFilesAsync(DirectoryInfo se`
`25`	`25`	`return await interactionService.ShowStatusAsync("Searching", async () =>`
`26`	`26`	`{`
`27`	`27`	`var appHostProjects = new List<FileInfo>();`
	`28`	`+ var lockObject = new object();`
`28`	`29`	`logger.LogDebug("Searching for project files in {SearchDirectory}", searchDirectory.FullName);`
`29`	`30`	`var enumerationOptions = new EnumerationOptions`
`30`	`31`	`{`
`@@ -52,7 +53,10 @@ await Parallel.ForEachAsync(projectFiles, async (projectFile, ct) =>`
`52`	`53`	`logger.LogDebug("Found AppHost project file {ProjectFile} in {SearchDirectory}", projectFile.FullName, searchDirectory.FullName);`
`53`	`54`	`var relativePath = Path.GetRelativePath(currentDirectory.FullName, projectFile.FullName);`
`54`	`55`	`interactionService.DisplaySubtleMessage(relativePath);`
`55`		`- appHostProjects.Add(projectFile);`
	`56`	`+ lock (lockObject)`
	`57`	`+ {`
	`58`	`+ appHostProjects.Add(projectFile);`
	`59`	`+ }`
`56`	`60`	`}`
`57`	`61`	`else`
`58`	`62`	`{`