Misconfigured `sendVariableValues` results in similar behavior as `{all: true}`

[Bryan Custer]

Issue Description

When configuring ApolloServerPluginUsageReporting, if you misconfigure sendVariableValues it seems to result in the same behavior as {all: true}.

Intended outcome

I think I would expect either an error due to the misconfiguration or a better logical fallback inline with {none: true}.

Actual outcome

We mistakenly set sendVariableValues to a function instead of transform and then saw all variables sent to apollo studio.

      sendVariableValues: ({ operationString, variables }) => {
        if (includes(operationString, "search")) {
          return { searchTerm: variables?.searchTerm };
        }

        // Return an empty object or null for other queries to avoid logging any data
        return {};
      }

I can fork and add this to git if you'd like

  it('Random config does not filter variables', () => {
    // @ts-ignore
    expect(makeTraceDetails(variables, { literally: 'anything but a good value' })).toEqual(
      nonFilteredOutput,
    );
  });

Link to Reproduction

https://codesandbox.io/p/devbox/stupefied-faraday-4vfmt4

Reproduction Steps

No response

[David Glasser]

Just to check — this is prevented by using TypeScript, right?

I'm not sure that "every single API needs to have runtime checks on every single argument to prevent misuse which could already be caught at compile time by the use of TypeScript (even just for typechecking on JS files, which it supports)" is the best use of resources.

[Bryan Custer]

I believe this is the line of code in question, where if no valid config is given to exclude and it is also not undefined then it just sends the raw value.

[Bryan Custer]

Just to check — this is prevented by using TypeScript, right?

That seems correct given the CodeSandbox. Our team uses just JS so didn't notice any issues.