Excessive stack depth error following upgrade to v6.0

[blecorre-mnp]

Describe the bug
When switching to Gel 6.0 and using the latest @gel/generate version, we get multiple Excessive stack depth comparing types ... errors as a result of tsc.

Reproduction
Following the initialization of a new project, simply try to generate the query builder with npx @gel/generate edgeql-js --target=ts and opening the generated file casting.ts is enough to see the error on our side. Here is the result of the tsc command.

Errors  Files
     5  dbschema/edgeql-js/casting.ts:53
    16  dbschema/edgeql-js/modules/std.ts:1859
     5  dbschema/edgeql-js/operators.ts:933
     2  dbschema/edgeql-js/set.ts:150

Expected behavior
It should not return any error, as things used to work fine when using older EdgeDB / Gel versions such as v5.8.

Versions

• OS: MacOS Sequoia 15.3.1
• EdgeDB version: 6.0+a940583
• EdgeDB CLI version: 6.1.2+1e45048
• @gel/generate version: 0.6.0
• Node/Deno version: 22.10.0

[scotttrinh]

Can you share what version of TypeScript you're using here? Seems to work fine for me on a relatively complex schema with TypeScript v5.7.3 but we're always teetering on the verge on complexity so maybe there is a regressive case in a different (earlier? beta?) version of TypeScript?

[blecorre-mnp]

Unfortunately, we are also currently running on TypeScript v5.7.3 as well..

$ npx tsc --version
Version 5.7.3

[blecorre-mnp]

@scotttrinh so you have something to try the issue on, I threw together this new basic Gel project with our current production schema. I was wrong in my comment above, it only breaks when the schema reaches a certain complexity. Let's hope we can find a solution!

[scotttrinh]

OK, that is incredibly helpful, thanks for getting a repro together! I'll try to grab some time this week to dig in a bit and see if there is some specific construct that is triggering this issue. In the meantime, you might try targeting a non-ts output style like esm and see if it works without the more complicated internal constructs that the full ts target uses? Thanks again for the thorough report!

[blecorre-mnp]

No worries, it's the least I can do! I've managed to make things work by migrating a few types outside of Gel, into our headless CMS. I've also deleted old deprecated types. I've also tried using --target=esm on the repro, doesn't seem to work with a simple tsc --noEmit index.ts.

We have somewhat of a complex schema due to the fact that I've chosen to bet a lot on Gel's computed properties, especially for our invoicing / quotes / invoices modules. After having such a schema in production for a little more than a year now, maybe we've reached Gel's natural technical limitation?

Anyway thank you for spending time on this, I hope it wont be too much of a bother!

[scotttrinh]

After having such a schema in production for a little more than a year now, maybe we've reached Gel's natural technical limitation?

You're definitely bumping into the edges of the complexity that maybe the type-system translation that the query builder is doing between EdgeQL and TypeScript. The query builder has always been a pretty ambitious project trying to maintain the type safety for arbitrarily complex expressions 😅 Gel itself is happy with really complex schemas, though, so keep on keeping on and we'll get this patched up.

Anyway thank you for spending time on this, I hope it wont be too much of a bother!

No bother at all, this is the job 👍