How do I know these changes are yours?

Every change on this page leads to its pull request in concourse/concourse, where the author and the merge date are visible.

Who decided to merge the changes into Concourse?

The maintainers of Concourse: they reviewed the change and merged it into their code. This page lists only merged changes, not open ones or ones closed without merging.

Where is the full write-up of this fix?

In Tech news: what was broken, what we changed, how we tested it and what the result is, in our own words.

What language is Concourse written in?

Go. Our changes on this page are in that language too.

How does sending a fix work?

We open a pull request with the fix in concourse/concourse. The maintainers review the change, and when they have remarks we revise it until they merge it.

Why do you fix other people's code?

Our clients' projects stand on projects like this. A bug fixed at the source is gone for everyone, and we know the code we build on from the inside.

Where are all your contributions?

On the Contributions page: 65 projects and 125 merged changes, each project with its own page.

Can you fix a bug in Concourse or another library my project uses?

Yes. We report and fix it at the source, and until the fixed version is released we leave a safe workaround in your project.

Concourse: our changes to an open source project

Q: How many of your changes were merged into Concourse?

1 merged change: merged on 5 October 2026.

A container-based CI/CD system written in Go.

All contributions

Concourse

github.com/concourse/concourse

Language: Go
GitHub stars: 7,915
Project site: concourse-ci.org

1merged change

Merged on 5 October 2026.

Number 21 of the 64 GitHub projects with our changes, by stars. First is Zed (91,587).

The change merged into Concourse

Variables in a task file are interpolated before the file is parsed, so they also work in fields the parser checks first.

Pull request #9717merged on 5 October 2026
Interpolate task file vars before parsing the file
github.com/concourse/concourse/pull/9717

How we tested it

New tests feed a task file with cpu: ((container_cpu_limit)) and memory: ((container_mem_limit)) and the vars 512 and 5gb, then check that the limits end up as 512 and 5 GiB. A second case checks that a file that is still invalid after interpolation fails with an error naming it.

Go

Our projects in this technology, their screens and when we choose it.

The Go page

The bug, the fix and the lesson

A summary of our Tech news write-up: what was broken, what we changed and what it means for our own work.

What was broken

A var in a numeric field broke the task

The task file was parsed before its vars were resolved. With memory: ((container_mem_limit)) the parser saw text where it expected a number, and the issue had been open since June 2020.

What we changed

Resolve first, parse after

Vars are resolved in the raw file contents and the result is parsed once. The error message also names the file.

What it taught us

Step order matters.

Variables must be substituted before the parser checks the file, or it rejects a valid configuration.

Go: our projects

Other projects with our changes: Go

21 projects in this technology have our merged changes. The bar is the repository's stars, next to it the number of our changes. Each row leads to the project's page.

Go: our projects and code

Go