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Re-find the picker node when it goes stale, and re-measure API 37

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CI found a flake this workstation could not, and fixing it overturned half of what
the previous commit recorded about API 37.

THE FLAKE. UiObject2 caches the AccessibilityNodeInfo it was found with, and
DocumentsUI is still settling when a node first appears -- its list rebinds, the
roots strip lays out, a window animates. If the node is replaced in that gap,
click() throws against the handle rather than missing the target:

  androidx.test.uiautomator.StaleObjectException
    at androidx.test.uiautomator.UiObject2.getAccessibilityNodeInfo(UiObject2.java:1042)
    at androidx.test.uiautomator.UiObject2.click(UiObject2.java:526)
    at SafPickerRoundTripTest.pickTheFixture(SafPickerRoundTripTest.kt:223)

It is not intermittent on a COLD emulator -- CI hit it on API 33, 34 and 35, every
one of them, on the first run. It never appeared here because the local emulator had
been warm for an hour. tapPickerNode now re-finds the node and taps again, three
attempts. That retries acquiring a handle to a node that has to be there anyway:
every attempt still goes through awaitPickerNode, which fails outright if it is
absent, so the MIME mutation's bite is untouched. Verified with `pm clear
com.google.android.documentsui` between runs, five for five green on API 34.

AND THE CORRECTION IT FORCED. The previous commit marked the whole class
@FailsOnEmulatorApi37 on the strength of two measured failures. One of them was
this bug. Re-measured with the fix, one method per fresh android-37.0 emulator:

  thePickedInputSurvivesARealRotation             INSTRUMENTATION_ABORTED:
                                                  System has crashed.
  pickingAFileThroughTheSystemPickerFillsInTheFileCard              PASSED

So a rotation, which rebuilds every surface at once, is what the gralloc mapper does
not survive; starting another app's activity is not. The marker moves to the one
method that earned it, and the picker test runs on the gating API 37 leg like
anything else. The workflow comment, run-e2e.sh and the doc all say that now.

The lesson is worth more than the measurement, and the doc keeps it: an annotation
is a claim about an IMAGE, and a broken test makes every image look broken. Both a
framework abort and a stale node read as "the run fell over". Re-measure after
fixing a test before deciding what the platform did.

Also measured rather than assumed, since it is what keeps the gating leg green: the
runner's annotation filter honours a class-level marker, expanding it to every
method. On API 34, `annotation=` selected exactly 4 tests (2 Media3EngineTest + 2
here) and `notAnnotation=` selected 55 with neither of these in it. CI's own gating
API 37 leg then reported 55 / 0 on the previous push. That is why moving the marker
to a single method is a narrowing rather than a repair.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
This commit is contained in:
JMR-dev
2026-08-24 21:14:07 -05:00
co-authored by Claude Opus 5
parent a3c835b7c9
commit 3925f1aa9f
4 changed files with 154 additions and 77 deletions
Download Patch File Download Diff File Expand all files Collapse all files
app/src/androidTest/java/org/libremediaconverter/saf/SafPickerRoundTripTest.kt
+74 -25
View File
@@ -10,6 +10,7 @@ import androidx.test.ext.junit.runners.AndroidJUnit4
import androidx.test.platform.app.InstrumentationRegistry
import androidx.test.uiautomator.By
import androidx.test.uiautomator.BySelector
import androidx.test.uiautomator.StaleObjectException
import androidx.test.uiautomator.UiDevice
import androidx.test.uiautomator.Until
import org.junit.After
@@ -74,36 +75,37 @@ import org.libremediaconverter.ui.TestTags
* `tools/local-emulator/run-e2e.sh` runs API 33-36 on the development host, and both tests pass
* there: **59 / 0 / 0 / 2 at API 33 and again at API 36**, whole suite, 2026-08-24.
*
* ### Why [FailsOnEmulatorApi37] is on this class
* ### Why only the rotation test carries [FailsOnEmulatorApi37]
*
* Measured, per that annotation's own rule, and measured **per test** rather than inferred from
* one of them — see `docs/api-37-emulator-crash.md`, which this is the first entry in that is not
* a codec.
*
* This is the first thing in the suite that touches system UI, and the android-37.x images are
* where that stops being free: surfaceflinger aborts inside the guest's Gralloc5 mapper, init
* This class is the first thing in the suite that touches system UI, and the android-37.x images
* are where that stops being free: surfaceflinger aborts inside the guest's Gralloc5 mapper, init
* SIGKILLs zygote with it, and the framework restarts underneath the run. Disabling SystemUI --
* the deviation the API 37 leg already makes -- removes the *idle* trigger, not this one. Driving
* DocumentsUI and rotating the display generate exactly the surface traffic that reaches the
* mapper. Both tests fail on `android-37.0` under `swangle_indirect` with SystemUI disabled, and
* they fail in the two shapes a framework restart produces:
* the deviation the API 37 leg already makes -- removes the *idle* trigger, not this one.
*
* The marker is on one method and not on the class, because that is what was measured, one method
* per fresh emulator, on `android-37.0` under `swangle_indirect`:
*
* ```
* thePickedInputSurvivesARealRotation
* INSTRUMENTATION_ABORTED: System has crashed. (5 hasReadColorBufferDma aborts; the run
* Expected 59 tests, received 50 never finished, taking 6 later tests out)
*
* pickingAFileThroughTheSystemPickerFillsInTheFileCard
* androidx.test.uiautomator.StaleObjectException (3 aborts; the picker's root node was
* at UiObject2.click(UiObject2.java:526) rebuilt between finding it and tapping it)
* thePickedInputSurvivesARealRotation INSTRUMENTATION_ABORTED: System has crashed.
* Expected 1 tests, received 0
* pickingAFileThroughTheSystemPickerFillsInTheFileCard PASSED
* ```
*
* The annotation says only that, and CI reads it twice, so this class runs on the advisory API 37
* leg and not on the gating one. **Do not read it as "a rotation is allowed to lose the file".**
* That is what API 33 through 36 are for, and they answer it.
* A rotation rebuilds every surface on screen at once, which the mapper does not survive; merely
* starting DocumentsUI does not.
*
* **The first version of this said the class, and it was wrong.** The picker test had failed at
* API 37 too -- with a `StaleObjectException` that turned out to be this file's own bug rather
* than the image's, and which CI then reproduced deterministically at API 33, 34 and 35. Fixing
* it ([tapPickerNode]) and re-measuring is what separated the two. An annotation is a claim about
* an image, and a broken test makes every image look broken; **re-measure after fixing a test
* before deciding what the platform did.**
*
* The annotation says only that, and CI reads it twice, so the rotation test runs on the advisory
* API 37 leg and not the gating one. **Do not read it as "a rotation is allowed to lose the
* file".** That is what API 33 through 36 are for, and they answer it.
*/
@UnstableApi
@FailsOnEmulatorApi37
@RunWith(AndroidJUnit4::class)
class SafPickerRoundTripTest {
@@ -162,6 +164,7 @@ class SafPickerRoundTripTest {
}
@Test
@FailsOnEmulatorApi37
fun thePickedInputSurvivesARealRotation() {
pickTheFixture()
// The identity hash rather than the Activity itself, so nothing here keeps a destroyed
@@ -213,20 +216,56 @@ class SafPickerRoundTripTest {
// types against Root.COLUMN_MIME_TYPES and drops the roots that cannot answer, so a filter
// the fixture root does not satisfy takes the root out of the picker altogether -- along
// with "Images", "Audio", "Videos" and "Documents", measured on API 34.
val root = awaitPickerNode(By.text(FixtureDocumentsProvider.ROOT_TITLE)) {
tapPickerNode(By.text(FixtureDocumentsProvider.ROOT_TITLE)) {
// Which screen the picker opens on is its own business: it lands on Recent, where the
// roots are a strip at the bottom, but a device with a populated Recent may need the
// drawer. Looking in the second place widens where the root is searched for; it does
// not weaken what has to be found, which is still this root.
device.findObject(By.desc(SHOW_ROOTS_DESCRIPTION))?.click()
}
root.click()
awaitPickerNode(By.text(FixtureDocumentsProvider.FIXTURE_DISPLAY_NAME)).click()
tapPickerNode(By.text(FixtureDocumentsProvider.FIXTURE_DISPLAY_NAME))
awaitNode(TestTags.Converter.FILE_CARD_NAME)
}
/**
* Finds the picker node [selector] names and taps it, re-finding it if it goes stale.
*
* **The re-finding is not padding, and this is not a retry of the assertion.** A `UiObject2`
* holds an `AccessibilityNodeInfo` captured when it was found, and DocumentsUI is still
* settling when the node first appears — its list rebinds, the roots strip lays out, a window
* animates. If the node is replaced in that gap, `click()` throws `StaleObjectException`
* against the handle rather than missing the target. Measured on a cold API 34 emulator:
*
* ```
* androidx.test.uiautomator.StaleObjectException
* at androidx.test.uiautomator.UiObject2.getAccessibilityNodeInfo(UiObject2.java:1042)
* at androidx.test.uiautomator.UiObject2.click(UiObject2.java:526)
* ```
*
* So what is retried is *acquiring a handle to a node that has to be there anyway* — every
* attempt still goes through [awaitPickerNode], which fails outright if the node is absent.
* The MIME mutation's bite is untouched: a root that is not in the picker is not found on any
* attempt, and the failure is still "the system picker never showed" rather than a stale one.
*/
private fun tapPickerNode(selector: BySelector, ifAbsent: () -> Unit = {}) {
var stale: StaleObjectException? = null
repeat(TAP_ATTEMPTS) { attempt ->
// ifAbsent only on the first attempt: it navigates, and re-navigating from a screen it
// already reached would walk away from the node.
val node = awaitPickerNode(selector, if (attempt == 0) ifAbsent else ({}))
device.waitForIdle()
try {
node.click()
return
} catch (e: StaleObjectException) {
stale = e
}
}
throw AssertionError("$selector kept going stale between finding it and tapping it", stale)
}
/**
* The picker node [selector] names, or a failure that says which one was missing.
*
@@ -270,6 +309,16 @@ class SafPickerRoundTripTest {
/** `Surface.ROTATION_0`, named rather than `0` so the comparison reads. */
const val NATURAL_ROTATION = 0
/**
* How many times a picker node may be re-found before its staleness is the finding.
*
* Three, not "until the timeout". Each attempt already waits up to [PICKER_TIMEOUT_MS] for
* the node to exist, so this bounds only the settling window after it does; a node that is
* still being replaced after three of those is telling you something about the device, and
* a loop that hid it would be the flake rather than the fix.
*/
const val TAP_ATTEMPTS = 3
/** DocumentsUI's drawer button. It carries no text, only this description. */
const val SHOW_ROOTS_DESCRIPTION = "Show roots"