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fix(zero-schema): Fix an issue with TS2589
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TS2589: Type instantiation is excessively deep and possibly infinite

The hint to solve this was here:

microsoft/TypeScript#30188 (comment)

The solution is to compute the types that cause problems step by step.
By using `T extends infer U`, we can force the computation of `T`
instead of deferring it. This way the instantiation does not get deeper.

 instantiation is excessively deep and possibly infinite
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@arv
arv committed Jan 27, 2025
1 parent c5d7dd4 commit 61ba089
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Showing 2 changed files with 247 additions and 26 deletions.
241 changes: 235 additions & 6 deletions packages/zero-schema/src/builder/schema-builder.test.ts
View file
Original file line number Diff line number Diff line change
@@ -1,12 +1,8 @@
/**
* Relationships as secondary.
*/

import {expectTypeOf, test} from 'vitest';
import {table, number, string} from './table-builder.js';
import {relationships} from './relationship-builder.js';
import type {Query} from '../../../zql/src/query/query.js';
import {relationships} from './relationship-builder.js';
import {createSchema} from './schema-builder.js';
import {number, string, table} from './table-builder.js';

const mockQuery = {
select() {
Expand Down Expand Up @@ -235,3 +231,236 @@ test('building a schema', () => {
}[]
>();
});

test('too many relationships', () => {
function makeTable<const N extends string>(name: N) {
return table(name)
.columns({
id: string(),
next: string(),
})
.primaryKey('id');
}

const a = makeTable('a');
const b = makeTable('b');
const c = makeTable('c');
const d = makeTable('d');
const e = makeTable('e');
const f = makeTable('f');
const g = makeTable('g');
const h = makeTable('h');
const i = makeTable('i');
const j = makeTable('j');
const k = makeTable('k');
const l = makeTable('l');
const m = makeTable('m');
const n = makeTable('n');
const o = makeTable('o');
const p = makeTable('p');
const qt = makeTable('q');
const r = makeTable('r');
const s = makeTable('s');
const t = makeTable('t');
const u = makeTable('u');
const v = makeTable('v');
const w = makeTable('w');
const x = makeTable('x');
const y = makeTable('y');
const z = makeTable('z');

const schema = createSchema(1, {
tables: [
a,
b,
c,
d,
e,
f,
g,
h,
i,
j,
k,
l,
m,
n,
o,
p,
qt,
r,
s,
t,
u,
v,
w,
x,
y,
z,
],
relationships: [
relationships(a, ({one}) => ({
toB: one({
sourceField: ['id'],
destField: ['next'],
destSchema: b,
}),
toC: one({
sourceField: ['id'],
destField: ['next'],
destSchema: c,
}),
toD: one({
sourceField: ['id'],
destField: ['next'],
destSchema: d,
}),
toE: one({
sourceField: ['id'],
destField: ['next'],
destSchema: e,
}),
toF: one({
sourceField: ['id'],
destField: ['next'],
destSchema: f,
}),
toG: one({
sourceField: ['id'],
destField: ['next'],
destSchema: g,
}),
toH: one({
sourceField: ['id'],
destField: ['next'],
destSchema: h,
}),
toI: one({
sourceField: ['id'],
destField: ['next'],
destSchema: i,
}),
toJ: one({
sourceField: ['id'],
destField: ['next'],
destSchema: j,
}),
toK: one({
sourceField: ['id'],
destField: ['next'],
destSchema: k,
}),
toL: one({
sourceField: ['id'],
destField: ['next'],
destSchema: l,
}),
toM: one({
sourceField: ['id'],
destField: ['next'],
destSchema: m,
}),
toN: one({
sourceField: ['id'],
destField: ['next'],
destSchema: n,
}),
toO: one({
sourceField: ['id'],
destField: ['next'],
destSchema: o,
}),
toP: one({
sourceField: ['id'],
destField: ['next'],
destSchema: p,
}),
toQ: one({
sourceField: ['id'],
destField: ['next'],
destSchema: qt,
}),
toR: one({
sourceField: ['id'],
destField: ['next'],
destSchema: r,
}),
toS: one({
sourceField: ['id'],
destField: ['next'],
destSchema: s,
}),
toT: one({
sourceField: ['id'],
destField: ['next'],
destSchema: t,
}),
toU: one({
sourceField: ['id'],
destField: ['next'],
destSchema: u,
}),
toV: one({
sourceField: ['id'],
destField: ['next'],
destSchema: v,
}),
toW: one({
sourceField: ['id'],
destField: ['next'],
destSchema: w,
}),
toX: one({
sourceField: ['id'],
destField: ['next'],
destSchema: x,
}),
toY: one({
sourceField: ['id'],
destField: ['next'],
destSchema: y,
}),
toZ: one({
sourceField: ['id'],
destField: ['next'],
destSchema: z,
}),
})),
],
});

const q = mockQuery as unknown as Query<typeof schema, 'a'>;
const q2 = q
.related('toB')
.related('toC')
.related('toD')
.related('toE')
.related('toF')
.related('toG')
.related('toH')
.related('toI')
.related('toJ')
.related('toK')
.related('toL')
.related('toM')
.related('toN')
.related('toO')
.related('toP')
.related('toQ')
.related('toR')
.related('toS')
.related('toT')
.related('toU')
.related('toV')
.related('toW')
.related('toX')
.related('toY')
.related('toZ');

// Before this commit the below line would generate 2 TS errors. One for the type number
// but more importantly it used to raise:
// TS2589: Type instantiation is excessively deep and possibly infinite

// @ts-expect-error type 'number' does not satisfy the constraint
expectTypeOf(q2).toEqualTypeOf<123>();
});
32 changes: 12 additions & 20 deletions packages/zql/src/query/query.ts
View file
Original file line number Diff line number Diff line change
@@ -1,13 +1,13 @@
/* eslint-disable @typescript-eslint/no-explicit-any */
import type {Expand, ExpandRecursive} from '../../../shared/src/expand.js';
import type {Schema as ZeroSchema} from '../../../zero-schema/src/builder/schema-builder.js';
import type {
LastInTuple,
SchemaValueToTSType,
TableSchema,
} from '../../../zero-schema/src/table-schema.js';
import type {SchemaValueToTSType} from '../../../zero-schema/src/table-schema.js';
import type {ExpressionFactory, ParameterReference} from './expression.js';
import type {TypedView} from './typed-view.js';
import type {Expand, ExpandRecursive} from '../../../shared/src/expand.js';
import type {Schema as ZeroSchema} from '../../../zero-schema/src/builder/schema-builder.js';

type Selector<E extends TableSchema> = keyof E['columns'];
export type NoJsonSelector<T extends TableSchema> = Exclude<
Expand Down Expand Up @@ -67,23 +67,15 @@ type DestRow<
? PullRow<DestTableName<TTable, TSchema, TRelationship>, TSchema>
: PullRow<DestTableName<TTable, TSchema, TRelationship>, TSchema> | undefined;

type AddSubreturn<
TExistingReturn,
TSubselectReturn,
TAs extends string,
> = undefined extends TExistingReturn
?
| (Exclude<TExistingReturn, undefined> & {
readonly [K in TAs]: undefined extends TSubselectReturn
? TSubselectReturn
: readonly TSubselectReturn[];
})
| undefined
: TExistingReturn & {
readonly [K in TAs]: undefined extends TSubselectReturn
? TSubselectReturn
: readonly TSubselectReturn[];
};
type AddSubreturn<TExistingReturn, TSubselectReturn, TAs extends string> = {
readonly [K in TAs]: undefined extends TSubselectReturn
? TSubselectReturn
: readonly TSubselectReturn[];
} extends infer TNewRelationship
? undefined extends TExistingReturn
? (Exclude<TExistingReturn, undefined> & TNewRelationship) | undefined
: TExistingReturn & TNewRelationship
: never;

export type PullTableSchema<
TTable extends string,
Expand Down

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