The config files VS Code never checks: DeviceTree overlays, TOML manifests, AutoHotkey v2 scripts

There is a category of bug that never shows up as a red squiggle. You edit an overlay, the editor stays quiet, you push, and three hours later someone on the hardware bench tells you the sensor is not on the I2C bus.

Here is the line that did it:

&i2c1 {
    status = "enabled";
};

DeviceTree accepts exactly two values in that property: "okay" and "disabled". Anything else is not an error — it is simply not "okay", so the node comes up switched off. "enabled" is the most natural word in English and the wrong word here, which is why this one keeps happening. The compiler does not warn. The editor does not warn. The board boots, and the device is missing.

The pattern generalises. The files that break a build hardest are the ones nobody writes a language server for:

[project]
port = 08080
limits = { cpu = 2, }

TOML rejects an integer with a leading zero outright, and an inline table may not carry a trailing comma. Both stop the parser dead. Your editor renders both in cheerful syntax colours, because the grammar highlighter and the parser are not the same program.

Same story in AutoHotkey. A script pinned with #Requires AutoHotkey v1 will refuse every v2 construct you paste into it, and MsgBox, text is v1 comma syntax that v2 reads as something else entirely. Same story in Inkling, where inkling "1.0" quietly rejects 2.0 graph and concept blocks.

What we did about it

We wrote 22 checks for exactly these silent breakages and put them in a VS Code extension, next to 46 snippets across 9 language packs — AutoHotkey v2, TOML, DeviceTree, MicroProfile/Java, Ren'Py, Swift, Inkling, Python colour rules, and repo config such as .editorconfig and CI workflow files.

The checks are regular-expression rules with a message written to say what the build will do, not what the rule is called. When you run it on the file above you get:

  2: This script is pinned to AutoHotkey v1, so every v2 snippet in this pack will fail to load here.
  7: DeviceTree accepts only "okay" or "disabled" here. Anything else leaves the node switched off at boot.
  9: This DeviceTree property is not closed with a semicolon, and the compiler will report the error on a later line.
 15: TOML rejects an integer with a leading zero. Write 9, or quote it as "09" if it is a code.
 16: A TOML inline table may not end with a trailing comma. The parser stops on this line.
 17: A credential is written straight into this file. Move it to an environment variable or a file the repository ignores.

Seven findings in seventeen lines, none of which the editor had marked.

Where the line is drawn

All 22 checks and all 46 snippets are free on the file you have open, and on just the lines you highlight. No key, no account, no watermark, no trial counter, nothing leaves your machine. If that is all you need, that is the whole product and you are done.

What a licence buys is a different axis, not a better version of the same thing: scale and handover. It runs the identical 22 checks across every overlay, manifest and script in the repository in one pass, and writes the findings out as a CSV, JSON or HTML file you can attach to a review or a release checklist. $29 once.

You can try the checks without installing anything — the free web page runs the same 22 rules in the browser.