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feat: demo null value defaulting #1358

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feat: demo null value defaulting #1358

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8 changes: 8 additions & 0 deletions libs/providers/ofrep-web/src/lib/ofrep-web-provider.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -299,6 +299,14 @@ export class OFREPWebProvider implements Provider {
};
}

if (resolved.value === undefined || resolved.value === null) {
return {
value: defaultValue,
flagMetadata: resolved.flagMetadata,
reason: resolved.reason || StandardResolutionReasons.DEFAULT,
};
}

if (typeof resolved.value !== type) {
return {
value: defaultValue,
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8 changes: 8 additions & 0 deletions libs/providers/ofrep/src/lib/ofrep-provider.spec.ts
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Expand Up @@ -60,6 +60,14 @@ describe('OFREPProvider should', () => {
);
});

it.each([true, false])('returns default if value is null', async (defaultValue) => {
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This test runs with 2 different defaults, and gets the default value both times since we send back a nullish value in OFREP

await expect(provider.resolveBooleanEvaluation('my-null-value-flag', defaultValue, {})).resolves.toStrictEqual({
value: defaultValue,
reason: 'DEFAULT',
flagMetadata: expect.objectContaining(TEST_FLAG_METADATA),
});
});

it('throw OFREPApiUnauthorizedError on HTTP 401', async () => {
await expect(provider.resolveBooleanEvaluation('my-flag', false, { expectedAuthHeader: 'secret' })).rejects.toThrow(
OFREPApiUnauthorizedError,
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8 changes: 6 additions & 2 deletions libs/providers/ofrep/src/lib/ofrep-provider.ts
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Expand Up @@ -94,7 +94,11 @@ export class OFREPProvider implements Provider {
return handleEvaluationError(result, defaultValue);
}

if (typeof result.value.value !== typeof defaultValue) {
if (
result.value.value !== undefined &&
result.value.value !== null &&
typeof result.value.value !== typeof defaultValue
) {
return {
value: defaultValue,
reason: StandardResolutionReasons.ERROR,
Expand All @@ -104,6 +108,6 @@ export class OFREPProvider implements Provider {
};
}

return toResolutionDetails(result.value);
return toResolutionDetails(result.value, defaultValue);
}
}
21 changes: 15 additions & 6 deletions libs/shared/ofrep-core/src/lib/api/ofrep-api.ts
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Expand Up @@ -191,13 +191,22 @@ export function handleEvaluationError<T>(

export function toResolutionDetails<T extends EvaluationFlagValue>(
result: EvaluationSuccessResponse,
defaultValue: T,
): ResolutionDetails<T> {
return {
value: result.value as T,
variant: result.variant,
reason: result.reason,
flagMetadata: result.metadata && toFlagMetadata(result.metadata),
};
if (result.value === undefined || result.value === null) {
return {
value: defaultValue,
reason: result.reason || StandardResolutionReasons.DEFAULT,
flagMetadata: result.metadata && toFlagMetadata(result.metadata),
};
} else {
return {
value: result.value as T,
variant: result.variant,
reason: result.reason,
flagMetadata: result.metadata && toFlagMetadata(result.metadata),
};
}
}

export function toFlagMetadata(metadata: object): FlagMetadata {
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17 changes: 12 additions & 5 deletions libs/shared/ofrep-core/src/test/handlers.ts
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Expand Up @@ -121,14 +121,21 @@ export const handlers = [
}

const scopeValue = new URL(info.request.url).searchParams.get('scope');
const key = info.params.key;
const reason = key.includes('null-value')
? StandardResolutionReasons.DEFAULT
: requestBody.context?.targetingKey
? StandardResolutionReasons.TARGETING_MATCH
: StandardResolutionReasons.STATIC;

const value = key.includes('null-value') ? null : true;
Comment on lines +125 to +131
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@toddbaert toddbaert Jul 16, 2025 •
edited
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Send back a value=null, variant=null and reason=DEFAULT, this is my preferred proposal for implementing a "defer to code default" evaluation in flagd. I think this would be non-breaking for other implementations.

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Would we need to send a variant at all?

const variant = key.includes('null-value') ? undefined : scopeValue ? 'scoped' : 'default';

return HttpResponse.json<EvaluationResponse>({
key: info.params.key,
reason: requestBody.context?.targetingKey
? StandardResolutionReasons.TARGETING_MATCH
: StandardResolutionReasons.STATIC,
variant: scopeValue ? 'scoped' : 'default',
value: true,
reason,
variant,
value,
metadata: TEST_FLAG_METADATA,
});
},
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