Kyle Carberry
4b52656958
The "Thinking..." indicator intermittently failed to render after submitting a message. The behavior depended on the order of events within a single WebSocket frame. ## Root Cause `flushMessageParts()` was called before **all** non-`message_part` events in the batch loop. When the server sent `[message_part, status:"running"]` in the same SSE chunk: 1. `message_part` → pushed to `partsBuf` 2. `status:"running"` → `flushMessageParts()` applied parts **first** → `streamState` became non-null → then `chatStatus` set to `"running"` 3. Subscriber saw `streamState != null && chatStatus == "running"` → `selectIsAwaitingFirstStreamChunk` returned `false` → no "Thinking..." When events arrived in the reverse order (`[status:"running", message_part]`), the indicator worked because the status was set before parts were applied. ## Fix - Move `flushMessageParts()` to only fire before `message` and `error` events (which need prior parts visible) - Add `discardBufferedParts()` for events that clear stream state (`status:"pending"/"waiting"`, `retry`) so the deferred `setTimeout(0)` flush doesn't re-populate cleared state - Status changes are now always applied before parts within a batch, and the deferred flush gives React one render cycle to show "Thinking..." | Event | Flush? | Rationale | |---|---|---| | `message` | YES | Durable commit must include all stream parts | | `error` | YES | Partial output should be visible alongside error | | `status` | NO | Status must be set before parts so "starting" phase renders | | `retry` | DISCARD | Retry clears stream state; flushing would re-populate it | | `queue_update` | NO | Doesn't interact with stream state | ## Tests (written first, failing before fix) 1. **"shows starting phase when message_part arrives before status:running in same batch"** — the exact bug scenario 2. **"shows starting phase when status:running arrives before message_part in same batch"** — verifies the "good" order still works 3. **"discards buffered parts when status transitions to pending"** — verifies parts don't leak through pending transitions All tests are deterministic (fake timers, no race conditions). <details><summary>Implementation plan & decision log</summary> ### Why not reorder events within the batch? Reordering would change the semantic ordering of events from the server, which could have subtle side effects. The simpler approach is to be selective about when parts are flushed. ### Why discard (not flush) before pending/waiting/retry? These events clear `streamState`. If parts were flushed before the clear, they'd be visible for one frame then disappear. If the deferred flush ran after the clear, it would re-populate the state. Discarding is the only correct behavior. ### Why keep flush before error? Errors should surface partial output so the user can see what the agent was doing when it failed. </details>
Coder enables organizations to set up development environments in their public or private cloud infrastructure. Cloud development environments are defined with Terraform, connected through a secure high-speed Wireguard® tunnel, and automatically shut down when not used to save on costs. Coder gives engineering teams the flexibility to use the cloud for workloads most beneficial to them.
- Define cloud development environments in Terraform
- EC2 VMs, Kubernetes Pods, Docker Containers, etc.
- Automatically shutdown idle resources to save on costs
- Onboard developers in seconds instead of days
Quickstart
The most convenient way to try Coder is to install it on your local machine and experiment with provisioning cloud development environments using Docker (works on Linux, macOS, and Windows).
# First, install Coder
curl -L https://coder.com/install.sh | sh
# Start the Coder server (caches data in ~/.cache/coder)
coder server
# Navigate to http://localhost:3000 to create your initial user,
# create a Docker template and provision a workspace
Install
The easiest way to install Coder is to use our
install script for Linux
and macOS. For Windows, use the latest ..._installer.exe file from GitHub
Releases.
curl -L https://coder.com/install.sh | sh
You can run the install script with --dry-run to see the commands that will be used to install without executing them. Run the install script with --help for additional flags.
See install for additional methods.
Once installed, you can start a production deployment with a single command:
# Automatically sets up an external access URL on *.try.coder.app
coder server
# Requires a PostgreSQL instance (version 13 or higher) and external access URL
coder server --postgres-url <url> --access-url <url>
Use coder --help to get a list of flags and environment variables. Use our install guides for a complete walkthrough.
Documentation
Browse our docs here or visit a specific section below:
- Templates: Templates are written in Terraform and describe the infrastructure for workspaces
- Workspaces: Workspaces contain the IDEs, dependencies, and configuration information needed for software development
- IDEs: Connect your existing editor to a workspace
- Administration: Learn how to operate Coder
- Premium: Learn about our paid features built for large teams
Support
Feel free to open an issue if you have questions, run into bugs, or have a feature request.
Join our Discord to provide feedback on in-progress features and chat with the community using Coder!
Integrations
We are always working on new integrations. Please feel free to open an issue and ask for an integration. Contributions are welcome in any official or community repositories.
Official
- VS Code Extension: Open any Coder workspace in VS Code with a single click
- JetBrains Toolbox Plugin: Open any Coder workspace from JetBrains Toolbox with a single click
- JetBrains Gateway Plugin: Open any Coder workspace in JetBrains Gateway with a single click
- Dev Container Builder: Build development environments using
devcontainer.jsonon Docker, Kubernetes, and OpenShift - Coder Registry: Build and extend development environments with common use-cases
- Kubernetes Log Stream: Stream Kubernetes Pod events to the Coder startup logs
- Self-Hosted VS Code Extension Marketplace: A private extension marketplace that works in restricted or airgapped networks integrating with code-server.
- Setup Coder: An action to setup coder CLI in GitHub workflows.
Community
- Provision Coder with Terraform: Provision Coder on Google GKE, Azure AKS, AWS EKS, DigitalOcean DOKS, IBMCloud K8s, OVHCloud K8s, and Scaleway K8s Kapsule with Terraform
- Coder Template GitHub Action: A GitHub Action that updates Coder templates
Contributing
We are always happy to see new contributors to Coder. If you are new to the Coder codebase, we have a guide on how to get started. We'd love to see your contributions!
Hiring
Apply here if you're interested in joining our team.