A
arktype•4w ago
Bobakanoosh

Type instantiation is excessively deep and possibly infinite

I have a set of event validators within a scope defined as below. Once I add enough, I get the error "Type instantiation is excessively deep and possibly infinite". In the code below, remove "y" from the event key and the error will go away. Is this expected behavior? Do I need to just define these differently? 
export const test = scope({
    event: "a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y",
    a: {
        type: "'a'",
        content: "null",
    },
    b: {
        type: "'b'",
        content: "null",
    },
    c: {
        type: "'c'",
        content: "null",
    },
    d: {
        type: "'d'",
        content: "null",
    },
    e: {
        type: "'e'",
        content: "null",
    },
    f: {
        type: "'f'",
        content: "null",
    },
    g: {
        type: "'g'",
        content: "null",
    },
    h: {
        type: "'h'",
        content: "null",
    },
    i: {
        type: "'i'",
        content: "null",
    },
    j: {
        type: "'j'",
        content: "null",
    },
    k: {
        type: "'k'",
        content: "null",
    },
    l: {
        type: "'l'",
        content: "null",
    },
    m: {
        type: "'m'",
        content: "null",
    },
    n: {
        type: "'n'",
        content: "null",
    },
    o: {
        type: "'o'",
        content: "null",
    },
    p: {
        type: "'p'",
        content: "null",
    },
    q: {
        type: "'q'",
        content: "null",
    },
    r: {
        type: "'r'",
        content: "null",
    },
    s: {
        type: "'s'",
        content: "null",
    },
    t: {
        type: "'t'",
        content: "null",
    },
    u: {
        type: "'u'",
        content: "null",
    },
    v: {
        type: "'v'",
        content: "null",
    },
    w: {
        type: "'w'",
        content: "null",
    },
    x: {
        type: "'x'",
        content: "null",
    },
    y: {
        type: "'y'",
        content: "null",
    },
}).export()
export const test = scope({
    event: "a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y",
    a: {
        type: "'a'",
        content: "null",
    },
    b: {
        type: "'b'",
        content: "null",
    },
    c: {
        type: "'c'",
        content: "null",
    },
    d: {
        type: "'d'",
        content: "null",
    },
    e: {
        type: "'e'",
        content: "null",
    },
    f: {
        type: "'f'",
        content: "null",
    },
    g: {
        type: "'g'",
        content: "null",
    },
    h: {
        type: "'h'",
        content: "null",
    },
    i: {
        type: "'i'",
        content: "null",
    },
    j: {
        type: "'j'",
        content: "null",
    },
    k: {
        type: "'k'",
        content: "null",
    },
    l: {
        type: "'l'",
        content: "null",
    },
    m: {
        type: "'m'",
        content: "null",
    },
    n: {
        type: "'n'",
        content: "null",
    },
    o: {
        type: "'o'",
        content: "null",
    },
    p: {
        type: "'p'",
        content: "null",
    },
    q: {
        type: "'q'",
        content: "null",
    },
    r: {
        type: "'r'",
        content: "null",
    },
    s: {
        type: "'s'",
        content: "null",
    },
    t: {
        type: "'t'",
        content: "null",
    },
    u: {
        type: "'u'",
        content: "null",
    },
    v: {
        type: "'v'",
        content: "null",
    },
    w: {
        type: "'w'",
        content: "null",
    },
    x: {
        type: "'x'",
        content: "null",
    },
    y: {
        type: "'y'",
        content: "null",
    },
}).export()
8 Replies
ssalbdivad
ssalbdivad•4w ago
The issue isn't the types themselves but the parsing logic for very long string embedded unions like this. Even if it's not necessarily that inefficient, it just hits TS recursion limits because of how branches need to b tracked. You could probably get away with this by splitting that union types into subsets, then merging them into a single union The union helper I'm adding in 2.2 may also be useful for this kind of thing The team has also mentioned increasing the recursion limits in tsgo 🙏
Bobakanoosh
BobakanooshOP•4w ago
export const test = scope({
    event1: "a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v",
    event2: "w | x | y",
    "event": "event1 | event2",
    a: {
        type: "'a'",
        content: "null",
    },
export const test = scope({
    event1: "a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v",
    event2: "w | x | y",
    "event": "event1 | event2",
    a: {
        type: "'a'",
        content: "null",
    },
Basically this?
ssalbdivad
ssalbdivad•4w ago
Yeah exactly
ssalbdivad
ssalbdivad•4w ago
E.g. this type isn't particularly expensive- I've never seen it listed anywhere when reviewing expensive types in the repo. But if you add |46, you get an infinite depth error.
No description
Bobakanoosh
BobakanooshOP•4w ago
Hmm. Kinda annoying to maintain thats unfortunate - planning on having tons of these. Maybe I'll try to restructure out of a scope, the only reason I had them like that was to be able to do module.event()
ssalbdivad
ssalbdivad•4w ago
Yeah if there's not a natural way to group them it kinda sucks I would probably just define large unions outside a scope as standalone types where possible. That will work particularly well with the new union helper, although the existing solution (chaining or) is quite tedious
Bobakanoosh
BobakanooshOP•4w ago
Ah well the thing is I need to be able to call the events from a single object so that as unvalidated events come in I can just validate with one easy call. I'll just do the scope unions for now since it would be just as much work to manually add the event types to some other list for my purpose. Is that union helper on a branch somewhere or a ticket so I can track it?
ssalbdivad
ssalbdivad•4w ago
https://github.com/arktypeio/arktype/issues/1319
GitHub
add method helpers for n-ary operators (or, and, merge) · Issue #13...
Request a feature 🤷 Motivation I am trying to compose typed enums into a larger union type for a variable number of types: export function Agent<Resources extends type<any>[]>(resources...

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