getStringOrFlow does not emit updates when removeKey is used

[MaderaJan]

Hi,

Description

When using getStringOrFlow(key) to observe preference changes, calling settings.removeKey(key) does not emit a new value to the flow collectors. However, if I use settings.putString(key, ""), the flow does emit the change as expected.

I’d like to clarify whether this behavior is intentional. Should removeKey trigger emissions in the flow, or is the current behavior by design?

Steps to Reproduce

1.	Collect from getStringOrFlow("some_key")
2.	Call settings.removeKey("some_key")
3.	Observe that the flow does not emit

Expected Behavior

Please confirm:
• Should removeKey emit to the flow?
• If not, is the recommendation to use putString(key, "") to ensure emission?

[russhwolf]

The way this is intended to work is that the listener gets called any time the value at that key changes. That could be due to calling a set method or remove. But if you call remove when there was no value there previously, the listener won't trigger because nothing changed.

[MaderaJan]

Thanks for the answer.

Apologies — the previous Steps to Reproduce were a bit too simplified. Here’s a more accurate sequence:

1. Start collecting from getStringOrFlow("some_key")
2. Call settings.putString("some_key", "some_value")
3. The flow emits "some_value" as expected
4. Call settings.removeKey("some_key")
5. The flow does **not** emit null or reflect any change

Interestingly, if I replace removeKey("some_key") with putString("some_key", ""), the flow does emit as expected.

[russhwolf]

Can you link a reproducer project? The following test case (added to BaseCoroutineExtensionsTest) passes on all implementations and platforms in CI

    @Test
    fun issue_235() = runTest {
        settings.getStringOrNullFlow("some_key").test {
            assertEquals(null, awaitItem())
            expectNoEvents()
            settings.putString("some_key", "some_value")
            assertEquals("some_value", awaitItem())
            expectNoEvents()
            settings.remove("some_key")
            assertEquals(null, awaitItem())
            expectNoEvents()
        }
    }

[MarkRS-UK]

I can't (immediately) submnit a reproducer either, but I am seeing the same problem.
Using "remove" to clear existing settings (so that defaults can be re-established) is not emitting anything into the flow.