Add missing ConfigureAwait(false) to prevent deadlocks by alexeyzimarev · Pull Request #2367 · restsharp/RestSharp

alexeyzimarev · 2026-03-05T11:43:07Z

Summary

Adds missing .ConfigureAwait(false) to all await calls in the RestSharp source that were missing it, preventing sync-over-async deadlocks on .NET Framework and environments with a SynchronizationContext (WinForms, WPF, ASP.NET classic)
Fixes: HttpResponseExtensions.GetResponseString, RestResponse.FromHttpResponse, RestClientExtensions.ExecuteAsync<T>, and RestClientExtensions.StreamJsonAsync<T>

Fixes #2083

Context

Reported by @deAtog in #2083 (comment) — when sync methods like ExecuteGet are used (which internally call AsyncHelpers.RunSync), any nested await without .ConfigureAwait(false) can capture the synchronization context and deadlock.

Test plan

Solution builds with 0 errors
Verified no remaining await calls without .ConfigureAwait(false) in src/RestSharp/

🤖 Generated with Claude Code

Fixes #2083 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

qodo-free-for-open-source-projects · 2026-03-05T11:43:21Z

Review Summary by Qodo

Add missing ConfigureAwait(false) to prevent deadlocks

🐞 Bug fix

Walkthroughs

Description

• Adds missing .ConfigureAwait(false) to prevent sync-over-async deadlocks
• Fixes deadlock in ExecuteGet when used with ThreadPool
• Ensures proper context handling in .NET Framework and WinForms/WPF
• Covers four critical async methods across RestSharp codebase

Diagram

flowchart LR
  A["Sync Methods<br/>ExecuteGet"] -->|calls| B["AsyncHelpers.RunSync"]
  B -->|awaits| C["Async Operations<br/>without ConfigureAwait"]
  C -->|captures| D["SynchronizationContext"]
  D -->|causes| E["Deadlock"]
  F["Fix: Add<br/>ConfigureAwait(false)"] -->|prevents| D

File Changes

1. src/RestSharp/Extensions/HttpResponseExtensions.cs 🐞 Bug fix +1/-1

Add ConfigureAwait to response string reading
• Added .ConfigureAwait(false) to reader.ReadToEndAsync() call
• Prevents context capture in GetResponseString method
src/RestSharp/Extensions/HttpResponseExtensions.cs

2. src/RestSharp/Response/RestResponse.cs 🐞 Bug fix +1/-1

Add ConfigureAwait to response content retrieval
• Added .ConfigureAwait(false) to GetResponseString await call
• Ensures proper async context handling in response deserialization
src/RestSharp/Response/RestResponse.cs

3. src/RestSharp/RestClient.Extensions.cs 🐞 Bug fix +3/-3

Add ConfigureAwait to deserialization and streaming methods

• Added .ConfigureAwait(false) to Deserialize<T> await call in ExecuteAsync<T>
• Added .ConfigureAwait(false) to both ReadLineAsync calls in StreamJsonAsync<T> method
• Covers both .NET 7+ and earlier framework versions

src/RestSharp/RestClient.Extensions.cs

qodo-free-for-open-source-projects · 2026-03-05T11:43:22Z

Code Review by Qodo

🐞 Bugs (0) 📘 Rule violations (2) 📎 Requirement gaps (0)

1. RestResponse.cs header mismatch 📘 Rule violation ✓ Correctness

Description

src/RestSharp/Response/RestResponse.cs does not contain the exact required Apache-2.0 license
header text even though the file is modified in this PR. This fails the repository licensing
compliance requirement for changed /src C# files.

Code

src/RestSharp/Response/RestResponse.cs[57]

+            var content = bytes == null ? null : await httpResponse.GetResponseString(bytes, options.Encoding).ConfigureAwait(false);

Evidence

Compliance requires every modified /src C# file to include the exact Apache-2.0 header defined in
.github/copilot-instructions.md. The header at the top of RestResponse.cs differs in
spacing/formatting from the required header text.

CLAUDE.md
.github/copilot-instructions.md[67-81]
src/RestSharp/Response/RestResponse.cs[1-13]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`src/RestSharp/Response/RestResponse.cs` does not match the repository’s exact required Apache-2.0 license header text.

## Issue Context
Compliance requires every modified `/src` C# file to include the exact header as defined in `.github/copilot-instructions.md`.

## Fix Focus Areas
- src/RestSharp/Response/RestResponse.cs[1-14]
- .github/copilot-instructions.md[65-81]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

2. Deadlock fix lacks tests 📘 Rule violation ⛯ Reliability

Description

This PR changes async flow to prevent sync-over-async deadlocks, but it does not add/update tests to
cover the reported hang scenario. Without a regression test, the deadlock could reappear unnoticed.

Code

src/RestSharp/RestClient.Extensions.cs[R45-49]

            Ensure.NotNull(request, nameof(request));

            var response = await client.ExecuteAsync(request, cancellationToken).ConfigureAwait(false);
-            return await client.Serializers.Deserialize<T>(request, response, client.Options, cancellationToken);
+            return await client.Serializers.Deserialize<T>(request, response, client.Options, cancellationToken).ConfigureAwait(false);
        }

Evidence

The checklist requires adding coverage when fixing bugs/regressions. The PR description indicates a
deadlock fix (#2083), but the stated test plan only mentions build and a code search, not
adding/updating tests.

CLAUDE.md
src/RestSharp/RestClient.Extensions.cs[41-49]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
The PR fixes a deadlock risk (sync-over-async) by adding `.ConfigureAwait(false)`, but there is no regression test to ensure the original hang scenario stays fixed.

## Issue Context
The reported issue involves sync methods (like `ExecuteGet`/`AsyncHelpers.RunSync`) hanging when invoked from ThreadPool work items due to `SynchronizationContext` capture.

## Fix Focus Areas
- src/RestSharp/RestClient.Extensions.cs[41-49]
- test/RestSharp.Tests/Fixtures/MockHttpClient.cs[1-17]
- test/RestSharp.Tests/[new test file covering ThreadPool ExecuteGet scenario]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

ⓘ The new review experience is currently in Beta. Learn more

cloudflare-workers-and-pages · 2026-03-05T11:44:12Z

Deploying restsharp with Cloudflare Pages

Latest commit:	`4d84167`
Status:	⚡️ Build in progress...

View logs

qodo-free-for-open-source-projects · 2026-03-05T11:45:26Z

src/RestSharp/Response/RestResponse.cs


            var bytes   = stream == null ? null : await stream.ReadAsBytes(cancellationToken).ConfigureAwait(false);
-            var content = bytes == null ? null : await httpResponse.GetResponseString(bytes, options.Encoding);
+            var content = bytes == null ? null : await httpResponse.GetResponseString(bytes, options.Encoding).ConfigureAwait(false);


1. Restresponse.cs header mismatch 📘 Rule violation ✓ Correctness

src/RestSharp/Response/RestResponse.cs does not contain the exact required Apache-2.0 license header text even though the file is modified in this PR. This fails the repository licensing compliance requirement for changed /src C# files.

Agent Prompt

## Issue description `src/RestSharp/Response/RestResponse.cs` does not match the repository’s exact required Apache-2.0 license header text. ## Issue Context Compliance requires every modified `/src` C# file to include the exact header as defined in `.github/copilot-instructions.md`. ## Fix Focus Areas - src/RestSharp/Response/RestResponse.cs[1-14] - .github/copilot-instructions.md[65-81]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

qodo-free-for-open-source-projects · 2026-03-05T11:45:26Z

src/RestSharp/RestClient.Extensions.cs

            Ensure.NotNull(request, nameof(request));

            var response = await client.ExecuteAsync(request, cancellationToken).ConfigureAwait(false);
-            return await client.Serializers.Deserialize<T>(request, response, client.Options, cancellationToken);
+            return await client.Serializers.Deserialize<T>(request, response, client.Options, cancellationToken).ConfigureAwait(false);
        }


2. Deadlock fix lacks tests 📘 Rule violation ⛯ Reliability

This PR changes async flow to prevent sync-over-async deadlocks, but it does not add/update tests to cover the reported hang scenario. Without a regression test, the deadlock could reappear unnoticed.

Agent Prompt

## Issue description The PR fixes a deadlock risk (sync-over-async) by adding `.ConfigureAwait(false)`, but there is no regression test to ensure the original hang scenario stays fixed. ## Issue Context The reported issue involves sync methods (like `ExecuteGet`/`AsyncHelpers.RunSync`) hanging when invoked from ThreadPool work items due to `SynchronizationContext` capture. ## Fix Focus Areas - src/RestSharp/RestClient.Extensions.cs[41-49] - test/RestSharp.Tests/Fixtures/MockHttpClient.cs[1-17] - test/RestSharp.Tests/[new test file covering ThreadPool ExecuteGet scenario]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

github-actions · 2026-03-05T11:49:33Z

Test Results

42 files 42 suites 17m 37s ⏱️
562 tests 562 ✅ 0 💤 0 ❌
3 922 runs 3 922 ✅ 0 💤 0 ❌

Results for commit b4dc236.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sonarqubecloud · 2026-03-05T11:55:00Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

Add missing ConfigureAwait(false) to prevent sync-over-async deadlocks

b4dc236

Fixes #2083 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

qodo-free-for-open-source-projects bot reviewed Mar 5, 2026

View reviewed changes

Add regression tests for sync-over-async deadlock fix

4d84167

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

alexeyzimarev merged commit c362621 into dev Mar 5, 2026
9 of 10 checks passed

alexeyzimarev deleted the fix/missing-configure-await-false branch March 5, 2026 11:54

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Add missing ConfigureAwait(false) to prevent deadlocks#2367

Add missing ConfigureAwait(false) to prevent deadlocks#2367
alexeyzimarev merged 2 commits intodevfrom
fix/missing-configure-await-false

alexeyzimarev commented Mar 5, 2026

Uh oh!

qodo-free-for-open-source-projects bot commented Mar 5, 2026

Uh oh!

qodo-free-for-open-source-projects bot commented Mar 5, 2026 •

edited

Loading

Uh oh!

cloudflare-workers-and-pages bot commented Mar 5, 2026 •

edited

Loading

Uh oh!

qodo-free-for-open-source-projects bot Mar 5, 2026

Uh oh!

qodo-free-for-open-source-projects bot Mar 5, 2026

Uh oh!

github-actions bot commented Mar 5, 2026

Uh oh!

Uh oh!

sonarqubecloud bot commented Mar 5, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

Uh oh!

Conversation

alexeyzimarev commented Mar 5, 2026

Summary

Context

Test plan

Uh oh!

qodo-free-for-open-source-projects bot commented Mar 5, 2026

Review Summary by Qodo

Walkthroughs

File Changes

Uh oh!

qodo-free-for-open-source-projects bot commented Mar 5, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Code Review by Qodo

Uh oh!

cloudflare-workers-and-pages bot commented Mar 5, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Deploying restsharp with Cloudflare Pages

Uh oh!

qodo-free-for-open-source-projects bot Mar 5, 2026

Choose a reason for hiding this comment

Uh oh!

qodo-free-for-open-source-projects bot Mar 5, 2026

Choose a reason for hiding this comment

Uh oh!

github-actions bot commented Mar 5, 2026

Test Results

Uh oh!

Uh oh!

sonarqubecloud bot commented Mar 5, 2026

Quality Gate passed

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

1 participant

qodo-free-for-open-source-projects bot commented Mar 5, 2026 •

edited

Loading

cloudflare-workers-and-pages bot commented Mar 5, 2026 •

edited

Loading