Reviving an Abandoned Open-Source Project: 6 Years of Atomic Calendar Revive | TotalDebug

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>_ Open Source · Home Assistant

Reviving an Abandoned Open-Source Project: 6 Years of Atomic Calendar Revive

Steven Marks

12 Jun 2026 · 7 min read

There’s a particular kind of sinking feeling you get as a user of open-source software. You’ve built your setup around a tool you love, it does exactly what you need, and then you notice the last commit was eighteen months ago. The issues are piling up. A platform update breaks it. And the maintainer, understandably, has moved on with their life.

Six years ago I hit exactly that wall with a Home Assistant calendar card called Atomic Calendar . I had two choices: rip it out of my dashboard and find something else, or roll up my sleeves and adopt it.

I picked the second one. That decision became Atomic Calendar Revive , and today it sits at 629 stars, 79 forks, and somewhere north of 1,700 commits , installed on dashboards I’ll never see all over the world.

This isn’t a tutorial. It’s the honest story of what it’s actually like to inherit, revive, and keep a popular open-source project alive for half a decade, and what it taught me as an engineer.

What it is (the 30-second version)

Atomic Calendar Revive is an advanced calendar card for Home Assistant ’s Lovelace dashboard. It pulls events from Google Calendar, CalDAV and any HA calendar entity, and renders them as either an agenda-style event list or a full month view, with a ridiculous number of configuration options and a visual editor so you don’t have to hand-write YAML. It’s TypeScript, built with Rollup, and distributed through HACS.

That’s the what. The interesting part is everything around it.

Lesson 1: a fork is a commitment, not a weekend project

When you fork an abandoned project to “just fix the one thing that’s broken,” you are quietly signing up to become its maintainer. The moment you publish that fork and a single other person installs it, you own their experience.

I didn’t fully appreciate this at the start. The first few weeks were genuinely fun: fix the breakage, tidy some code, ship a release. Then the issues started arriving. Not because I’d done anything wrong, but because a working project attracts users, and users find edge cases you never imagined . Different calendar providers, time zones I’d never tested, locales, themes, devices.

A fork isn’t “I fixed it for me.” It’s “I’m now responsible for fixing it for everyone.” That’s a much bigger sentence than it looks.

Lesson 2: backwards compatibility is sacred

Here’s the thing about a card that’s installed on thousands of dashboards: every one of those dashboards is a YAML file someone wrote by hand, and they do not want to touch it again.

The single fastest way to lose the goodwill you’ve earned is to ship a release that silently changes a config option and breaks people’s carefully tuned layouts. I learned to treat the configuration surface as an API contract. Renaming a property isn’t a tidy-up. It’s a breaking change that needs a deprecation path, a fallback, and a clear note in the changelog.

It is genuinely harder to keep an option working than to add a new one. Most of the discipline in maintaining mature software is in what you don’t break.

Lesson 3: you’re standing on a moving platform

A Home Assistant card doesn’t run in a vacuum. It runs inside Home Assistant’s frontend, which ships updates roughly monthly, and occasionally changes the APIs and styling primitives your card depends on.

So a chunk of maintenance has nothing to do with new features at all. It’s keeping pace with the platform underneath you: a frontend change lands, something subtle shifts in how cards are styled or how entities are accessed, and suddenly there’s a flurry of “it stopped working after I updated HA” issues. None of that is glamorous, and none of it shows up as a shiny new feature, but it’s the difference between a project that’s alive and one that’s quietly dying.

Lesson 4: automate everything that isn’t the actual work

The only way to sustain this around a full-time job is to be ruthless about automation. If a task is boring and repeatable, it should not involve me.

Releases are the obvious one. I’m not hand-writing changelogs or guessing version bumps for a project with this much churn. That’s exactly the chore I wrote about in Automating Releases and Versioning with release-please. CI builds the card, runs the checks, and a merged release PR publishes it. My job is to review and merge; the machine does the rest.

Issue templates, linting, build pipelines: every bit of automation you add buys back the time and energy you need for the part only a human can do.

Lesson 5: triage, and the art of saying “no, but…”

This was the hardest one for me, and it’s not technical at all.

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