1 reply

Bug: @convex-dev/migrations component loses fields during ctx.db.patch with Doc object

🪲Bug Report

Bug:

@convex-dev/migrations

@convex-dev/migrations

component loses fields during

ctx.db.patch

ctx.db.patch

with Doc object

Versions affected: All tested — 0.1.6, 0.3.1 (latest)

Convex version: 1.29.3

Reproduction: Any

migrations.define()

migrations.define()

migrations.runner()

migrations.runner()

migration that processes at least one batch.

Error:

Failed to insert or update a document in table "migrations" because it does not match
the schema: Object is missing the required field `cursor`.

Object: {latestStart: 1772663804832.0, name: "migrations:runBackfillPhoneLookups",
         processed: 10.0, workerId: "kc2d5e61pn8eap43gpdap65zr98291jh"}

Validator: v.object({cursor: v.union(v.string(), v.null()), isDone: v.boolean(), ...})

Failed to insert or update a document in table "migrations" because it does not match
the schema: Object is missing the required field `cursor`.

Object: {latestStart: 1772663804832.0, name: "migrations:runBackfillPhoneLookups",
         processed: 10.0, workerId: "kc2d5e61pn8eap43gpdap65zr98291jh"}

Validator: v.object({cursor: v.union(v.string(), v.null()), isDone: v.boolean(), ...})

Root cause: In the component's

migrate

migrate

mutation (

src/component/lib.ts:191

src/component/lib.ts:191

):

await ctx.db.patch(state._id, state);

state

state

is a Doc retrieved via

ctx.db.get()

ctx.db.get()

in the same transaction, then mutated in-place:

state.cursor = result.continueCursor;  // string from pagination
state.isDone = result.isDone;          // boolean
state.processed += result.processed;   // number (this one works)

state.cursor = result.continueCursor;  // string from pagination
state.isDone = result.isDone;          // boolean
state.processed += result.processed;   // number (this one works)

At patch time,

cursor

cursor

and

isDone

isDone

are missing from the serialized object (they become

undefined

undefined

, which Convex treats as field removal). Other fields like

processed

processed

and

workerId

workerId

serialize correctly. This suggests the Doc object doesn't reliably reflect in-place property mutations during serialization, possibly specific to the component execution context.

Suggested fix: Destructure before patching:

const { _id, _creationTime, ...fields } = state;
await ctx.db.patch(_id, fields);

const { _id, _creationTime, ...fields } = state;
await ctx.db.patch(_id, fields);

Workaround: We bypassed the migrations framework entirely and wrote a self-paginating internal mutation using ctx.scheduler.runAfter for recursion.

Convex Community•2w ago•

1 reply

andrew_stoke

Bug: @convex-dev/migrations component loses fields during ctx.db.patch with Doc object

🪲Bug Report

Bug:

@convex-dev/migrations

@convex-dev/migrations

component loses fields during

ctx.db.patch

ctx.db.patch

with Doc object

Versions affected: All tested — 0.1.6, 0.3.1 (latest)

Convex version: 1.29.3

Reproduction: Any

migrations.define()

migrations.define()

migrations.runner()

migrations.runner()

migration that processes at least one batch.

Error:

Failed to insert or update a document in table "migrations" because it does not match
the schema: Object is missing the required field `cursor`.

Object: {latestStart: 1772663804832.0, name: "migrations:runBackfillPhoneLookups",
         processed: 10.0, workerId: "kc2d5e61pn8eap43gpdap65zr98291jh"}

Validator: v.object({cursor: v.union(v.string(), v.null()), isDone: v.boolean(), ...})

Failed to insert or update a document in table "migrations" because it does not match
the schema: Object is missing the required field `cursor`.

Object: {latestStart: 1772663804832.0, name: "migrations:runBackfillPhoneLookups",
         processed: 10.0, workerId: "kc2d5e61pn8eap43gpdap65zr98291jh"}

Validator: v.object({cursor: v.union(v.string(), v.null()), isDone: v.boolean(), ...})

Root cause: In the component's

migrate

migrate

mutation (

src/component/lib.ts:191

src/component/lib.ts:191

):

await ctx.db.patch(state._id, state);

state

state

is a Doc retrieved via

ctx.db.get()

ctx.db.get()

in the same transaction, then mutated in-place:

state.cursor = result.continueCursor;  // string from pagination
state.isDone = result.isDone;          // boolean
state.processed += result.processed;   // number (this one works)

state.cursor = result.continueCursor;  // string from pagination
state.isDone = result.isDone;          // boolean
state.processed += result.processed;   // number (this one works)

At patch time,

cursor

cursor

and

isDone

isDone

are missing from the serialized object (they become

undefined

undefined

, which Convex treats as field removal). Other fields like

processed

processed

and

workerId

workerId

const { _id, _creationTime, ...fields } = state;
await ctx.db.patch(_id, fields);

const { _id, _creationTime, ...fields } = state;
await ctx.db.patch(_id, fields);

Workaround: We bypassed the migrations framework entirely and wrote a self-paginating internal mutation using ctx.scheduler.runAfter for recursion.

Bug: @convex-dev/migrations component loses fields during ctx.db.patch with Doc object

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