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fix: type single relation/select/file fields as single, not arrays #35

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Karnak19 merged 2 commits into from
Jun 1, 2026
Merged

fix: type single relation/select/file fields as single, not arrays #35

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3b93ce0
fix: type single relation/select/file fields as single, not arrays
Karnak19 Jun 1, 2026
c050a63
test(zod): add maxSelect=0 regression test for single-value fields
Karnak19 Jun 1, 2026
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12 changes: 12 additions & 0 deletions .changeset/single-ref-maxselect.md
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@@ -0,0 +1,12 @@
---
"@karnak19/pbkit": patch
"@karnak19/pbkit-zod": patch
---

Fix single relation/select/file fields being typed as arrays

PocketBase stores single-value relation, select, and file fields with `maxSelect: 0`, not `1`. The generators only treated `maxSelect === 1` as single, so these fields were incorrectly typed as arrays (`string[]`, `(...)[]`, `z.array(...)`).

Generation now follows PocketBase's own rule — a field is multiple only when `maxSelect > 1` — via a shared `isMultipleField` helper used by the type generator, relation extraction, and the Zod plugin.

Closes #28
15 changes: 7 additions & 8 deletions packages/pbkit-zod/src/generate.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ import type {
CollectionsConfig,
} from "@karnak19/pbkit";
import type { PbkitPlugin, PluginContext, PluginOutputFile } from "@karnak19/pbkit";
import { isCollectionExcluded } from "@karnak19/pbkit";
import { isCollectionExcluded, isMultipleField } from "@karnak19/pbkit";

function pascalCase(name: string): string {
return name
Expand Down Expand Up @@ -66,25 +66,24 @@ function fieldToZod(field: CollectionField): string {
schema = "z.string().datetime({ offset: true })";
break;
case "select": {
const multiple = isMultipleField(field);
const values = field.options.values;
if (values && values.length > 0) {
const union = values.map((v) => JSON.stringify(v)).join(", ");
schema = field.options.maxSelect === 1
? `z.enum([${union}])`
: `z.array(z.enum([${union}]))`;
schema = multiple
? `z.array(z.enum([${union}]))`
: `z.enum([${union}])`;
if (field.options.maxSelect && field.options.maxSelect > 1) {
schema += `.max(${field.options.maxSelect})`;
}
} else {
schema = field.options.maxSelect === 1 ? "z.string()" : "z.array(z.string())";
schema = multiple ? "z.array(z.string())" : "z.string()";
}
break;
}
case "relation":
schema = field.options.maxSelect === 1 ? "z.string()" : "z.array(z.string())";
break;
case "file":
schema = field.options.maxSelect === 1 ? "z.string()" : "z.array(z.string())";
schema = isMultipleField(field) ? "z.array(z.string())" : "z.string()";

@github-actions github-actions Bot Jun 1, 2026

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Missing regression test for maxSelect: 0 in the Zod plugin.

The type generator gains three explicit maxSelect: 0 tests in type-generator.test.ts, but the Zod plugin's zod.test.ts has no equivalent. The test fixture (full-schema.json) uses maxSelect: 1 for every single-value relation/select/file field, so the snapshot and assertion tests never exercise the maxSelect: 0 path that this PR fixes.

Impact: if someone later replaces isMultipleField(field) with a direct maxSelect === 1 check (re-introducing the original bug), CI will not catch it in the Zod output.

Fix: either add a maxSelect: 0 field to packages/pbkit-zod/src/test/fixtures/full-schema.json (and update the snapshot), or add a targeted unit test similar to the type generator's:

test("relation maxSelect=0 → z.string() (not array)", () => {
  const schema = parseJson({ collections: [{ name: "x", type: "base", fields: [{ name: "ref", type: "relation", system: false, maxSelect: 0, collectionId: "abc" }] }] });
  const output = generateZod(schema, { ir: schema, typesImport: "./t", sdkImport: "./s" });
  expect(output).toContain("ref: z.string()");
});

@Karnak19 Karnak19 Jun 1, 2026

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Good catch — added in c050a63. New regression test in zod.test.ts builds a collection with maxSelect: 0 relation/select/file fields and asserts they generate z.string() / z.enum([...]) (not z.array(...)), so a future regression in fieldToZod would now fail CI.

break;
case "json":
schema = "z.unknown()";
Expand Down
24 changes: 24 additions & 0 deletions packages/pbkit-zod/src/test/zod.test.ts
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Expand Up @@ -129,6 +129,30 @@ describe("generateZod", () => {
});
});

describe("generateZod single-value fields with maxSelect=0 (regression #28)", () => {
// PocketBase stores single relation/select/file fields with maxSelect: 0.
const ir0 = parseJson([
{
id: "c1",
name: "things",
type: "base",
fields: [
{ name: "ref", type: "relation", system: false, required: false, maxSelect: 0, collectionId: "abc" },
{ name: "status", type: "select", system: false, required: false, maxSelect: 0, values: ["a", "b"] },
{ name: "doc", type: "file", system: false, required: false, maxSelect: 0 },
],
},
]);
const out = generateZod(ir0, { ir: ir0, typesImport: "./types.gen", sdkImport: "./sdk.gen" });

test("relation/select/file are single, not arrays", () => {
expect(out).toContain("ref: z.string()");
expect(out).toContain('status: z.enum(["a", "b"])');
expect(out).toContain("doc: z.string()");
expect(out).not.toContain("z.array(");
});
});

describe("zodPlugin", () => {
test("has correct name", () => {
expect(zodPlugin.name).toBe("@karnak19/pbkit-zod");
Expand Down
1 change: 1 addition & 0 deletions packages/pbkit/src/index.ts
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Expand Up @@ -7,6 +7,7 @@ export {
normalizeCollection,
normalizeField,
extractRelations,
isMultipleField,
} from "./schema-parser";

export type {
Expand Down
2 changes: 1 addition & 1 deletion packages/pbkit/src/schema-parser/index.ts
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Expand Up @@ -2,7 +2,7 @@ export { parseJson, parseJsonFile } from "./parse-json"
export { parseApi } from "./parse-api"
export type { ApiParseOptions } from "./parse-api"
export { parseSqlite } from "./parse-sqlite"
export { normalizeSchema, normalizeCollection, normalizeField, extractRelations } from "./normalize"
export { normalizeSchema, normalizeCollection, normalizeField, extractRelations, isMultipleField } from "./normalize"
export type {
CollectionType,
FieldType,
Expand Down
11 changes: 10 additions & 1 deletion packages/pbkit/src/schema-parser/normalize.ts
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Expand Up @@ -10,6 +10,15 @@ import type {

const FIELD_CORE_KEYS = new Set(["id", "name", "type", "system", "required"])

/**
* PocketBase treats a relation/select/file field as "multiple" only when
* maxSelect is greater than 1. A maxSelect of 0 or 1 (or unset) is a single
* value — matching PocketBase's own `IsMultiple()` (maxSelect > 1).
*/
export function isMultipleField(field: CollectionField): boolean {
return (field.options.maxSelect ?? 0) > 1
}

export function normalizeField(raw: Record<string, unknown>): CollectionField {
const options: FieldOptions = {}
for (const [key, value] of Object.entries(raw)) {
Expand Down Expand Up @@ -57,7 +66,7 @@ export function extractRelations(collections: CollectionSchema[]): Relation[] {
collectionName: collection.name,
targetCollectionId: targetId,
targetCollectionName: targetName,
multiple: field.options.maxSelect !== 1,
multiple: isMultipleField(field),
cascadeDelete: field.options.cascadeDelete ?? false,
})
}
Expand Down
17 changes: 17 additions & 0 deletions packages/pbkit/src/test/type-generator.test.ts
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Expand Up @@ -64,6 +64,23 @@ describe("fieldTypeToTs", () => {
const f = field("file", { maxSelect: 3 })
expect(fieldTypeToTs(f, {})).toBe("string[]")
})

// Regression (#28): PocketBase stores single relation/select/file fields with
// maxSelect: 0, not 1. These must still be treated as single values.
test("relation maxSelect=0 → string", () => {
const f = field("relation", { maxSelect: 0, collectionId: "abc" })
expect(fieldTypeToTs(f, {})).toBe("string")
})

test("select maxSelect=0 → union literal (single)", () => {
const f = field("select", { maxSelect: 0, values: ["draft", "published"] })
expect(fieldTypeToTs(f, {})).toBe('"draft" | "published"')
})

test("file maxSelect=0 → string", () => {
const f = field("file", { maxSelect: 0 })
expect(fieldTypeToTs(f, {})).toBe("string")
})
})

describe("generate", () => {
Expand Down
9 changes: 5 additions & 4 deletions packages/pbkit/src/type-generator/generate.ts
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@@ -1,4 +1,5 @@
import type { SchemaIR, CollectionSchema, CollectionField } from "../schema-parser"
import { isMultipleField } from "../schema-parser"
import type { GenerateOptions } from "./types"
import { isCollectionExcluded, type CollectionsConfig } from "../config"

Expand Down Expand Up @@ -26,17 +27,17 @@ export function fieldTypeToTs(field: CollectionField, options: GenerateOptions):
case "date":
return options.dateStrings === false ? "Date" : "string"
case "select": {
const multiple = isMultipleField(field)
const values = field.options.values
if (values && values.length > 0) {
const union = values.map(v => JSON.stringify(v)).join(" | ")
return field.options.maxSelect === 1 ? union : `(${union})[]`
return multiple ? `(${union})[]` : union
}
return field.options.maxSelect === 1 ? "string" : "string[]"
return multiple ? "string[]" : "string"
}
case "relation":
return field.options.maxSelect === 1 ? "string" : "string[]"
case "file":
return field.options.maxSelect === 1 ? "string" : "string[]"
return isMultipleField(field) ? "string[]" : "string"
case "json":
return "unknown"
case "password":
Expand Down
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