From d59e9acce5e0d12987f923d8e3f110f7870b2415 Mon Sep 17 00:00:00 2001 From: Jason Ross Date: Wed, 26 Aug 2026 22:42:46 -0500 Subject: [PATCH 1/2] C6 (#140): OutputPublisher's guarded branches, three of them guarding a delete destinationIsKnownEmpty's three short-circuits -- no SIZE column, no row, a null cell -- each had to answer false and none was tested. Its KDoc is unambiguous about why: "this decides whether a delete is allowed and 'I could not tell' must never authorise one." The existing tests only ever drove a provider that answers properly, where the answer is zero and the delete is correct. Getting the uncertain cases backwards costs the user a file they already had, on a save that failed. Also discardStaged's null parentFile, and sweepStaging's null listing -- which is not the case the existing `tolerates a staging directory that does not exist yet` covers, because stagingDir's own mkdirs() recreates a missing directory and it then lists as empty. Only a path that cannot be a directory makes listFiles() answer null. Five mutations, three bite: drop !row.isNull(size) short-circuit test red drop row.moveToFirst() five tests red parentFile!! instead of ?: return false parentless test red size >= 0 -> size >= -1 GREEN, does not bite parentless treated as staged GREEN -- bad mutation, see below The first green one is recorded in the test as a named exemption. Measured: getColumnIndex returns -1 for an absent column and isNull(-1) throws CursorIndexOutOfBoundsException, which the surrounding runCatching already turns into `?: false`. Same answer, reached by the exception path, so no behavioural test can pin that conjunct. It stays anyway -- control flow through an exception is worse than a comparison, and another Cursor implementation need not throw. The second was my mistake rather than a finding: substituting stagingDir for the null parent reaches `return false` by a different route, so it proves nothing. parentFile!! is the honest mutation and it goes red. :197, :235 and :258 are now covered. What is left in this file is exactly what the ticket scoped out: :173-174 (#142) and :267 (#143). Co-Authored-By: Claude Opus 5 (1M context) --- .../convert/OutputPublisherPublishTest.kt | 49 +++++++++++++++++++ .../convert/OutputPublisherStagingTest.kt | 26 ++++++++++ 2 files changed, 75 insertions(+) diff --git a/app/src/test/java/org/libremediaconverter/convert/OutputPublisherPublishTest.kt b/app/src/test/java/org/libremediaconverter/convert/OutputPublisherPublishTest.kt index c670a67..aa7fd24 100644 --- a/app/src/test/java/org/libremediaconverter/convert/OutputPublisherPublishTest.kt +++ b/app/src/test/java/org/libremediaconverter/convert/OutputPublisherPublishTest.kt @@ -20,6 +20,9 @@ import java.io.OutputStream /** What a destination volume says when it fills up mid-write. */ private const val NO_SPACE = "No space left on device" +/** How far a failing copy gets before the volume "fills up". Any value below the payload does. */ +private const val PARTIAL_BYTES = 512 + /** * A sink that behaves like a volume filling up. * @@ -75,6 +78,8 @@ class OutputPublisherPublishTest { private val payload = ByteArray(8192) { (it % 251).toByte() } + /** How far a failing copy gets before the volume "fills up". Any value below the payload does. */ + private val documentUri: Uri = Uri.parse("content://$DOCUMENTS_AUTHORITY/document/holiday.mp4") private val plainUri: Uri = Uri.parse("content://$PLAIN_AUTHORITY/document/holiday_plain.mp4") private val deadUri: Uri = Uri.parse("content://org.libremediaconverter.nonexistent/document/gone.mp4") @@ -203,6 +208,50 @@ class OutputPublisherPublishTest { assertEquals(emptyList(), FakeSafProvider.deleteRequests) } + @Test + fun `a destination whose size cannot be determined is never deleted`() { + // The three short-circuits in destinationIsKnownEmpty, and the reason its KDoc gives for + // each of them answering false: + // + // "this decides whether a delete is allowed and 'I could not tell' must never authorise + // one." + // + // The contrast is `a copy that fails partway leaves nothing at the destination` above: a + // provider that *does* say zero gets the delete. These say nothing, so they must not. + // Getting this backwards costs the user a file they already had, on a save that failed. + // + // Named exemption: of the three conjuncts, `size >= 0` cannot be falsified behaviourally. + // Measured -- getColumnIndex returns -1 for an absent column, and isNull(-1) throws + // CursorIndexOutOfBoundsException, which the surrounding runCatching already turns into + // `?: false`. So relaxing it to `size >= -1` leaves this test green: same answer, reached + // by the exception path instead. The guard should stay -- control flow through an exception + // is worse than a comparison, and another Cursor implementation need not throw -- but no + // assertion here pins it, and saying so beats implying the missing-column case covers it. + // `!row.isNull(size)` and `row.moveToFirst()` do both bite. + listOf( + RowShape.NO_SIZE_COLUMN to "a cursor with no SIZE column", + RowShape.NULL_SIZE to "a cursor whose SIZE cell is null", + RowShape.NO_ROWS to "a cursor holding no rows", + ).forEach { (shape, description) -> + FakeSafProvider.deleteRequests.clear() + FakeSafProvider.backingFile(documentUri).writeBytes(ByteArray(0)) + FakeSafProvider.rowShape = shape + failMidCopy(documentUri, afterBytes = PARTIAL_BYTES) + + assertThrows(IOException::class.java) { publisher.publish(staged, documentUri) } + + assertEquals( + "$description must not authorise a delete", + emptyList(), + FakeSafProvider.deleteRequests, + ) + assertTrue( + "$description must leave the destination where it was", + FakeSafProvider.backingFile(documentUri).exists(), + ) + } + } + @Test fun `a copy that succeeds delivers every byte and deletes nothing`() { shadowOf(context.contentResolver).registerOutputStreamSupplier(documentUri) { diff --git a/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt b/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt index f778f5a..a1d2365 100644 --- a/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt +++ b/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt @@ -1,6 +1,7 @@ package org.libremediaconverter.convert import org.junit.Assert.assertFalse +import org.junit.Assert.assertNull import org.junit.Assert.assertTrue import org.junit.Before import org.junit.Test @@ -99,4 +100,29 @@ class OutputPublisherStagingTest { publisher.sweepStaging() } + + @Test + fun `the sweep tolerates a staging path that is not a directory`() { + // The other half of `listFiles() ?: return`, and not the same as the case above: a missing + // directory is created by `stagingDir`'s own mkdirs() and lists as empty. Only a path that + // cannot be a directory makes listFiles() answer null, and a sweep that dereferenced that + // would take the app down on a launch rather than on a conversion -- AppStartSweepTest is + // where this runs from. + File(cacheDir, "conversions").deleteRecursively() + File(cacheDir, "conversions").writeBytes(ByteArray(8)) + + publisher.sweepStaging() + } + + @Test + fun `discarding a file with no parent at all is refused`() { + // A relative name has no parent directory, so `staged.parentFile` is null. The handle + // reaches the ViewModel as a path string out of WorkInfo.outputData and is turned straight + // into a File, so this is not a shape the caller can rule out -- and the guard has to + // answer false rather than dereference it. + val parentless = File("holiday.mp4") + assertNull("the fixture is supposed to have no parent", parentless.parentFile) + + assertFalse("a file with no parent is not in staging", publisher.discardStaged(parentless)) + } } -- 2.47.3 From c60d5d54c6fe5a22f9725bf36c88a1cbfd40c9c1 Mon Sep 17 00:00:00 2001 From: Jason Ross Date: Thu, 27 Aug 2026 07:12:32 -0500 Subject: [PATCH 2/2] Stop the staging fixture losing a race with the app-start sweep (#159) `the sweep tolerates a staging path that is not a directory` failed once on run 33069641674, against 468 tests that pass on this machine including under `--rerun-tasks`: java.io.FileNotFoundException at OutputPublisherStagingTest.kt:112 468 tests completed, 1 failed Line 112 was `writeBytes` immediately after `deleteRecursively()`. `FileOutputStream` answers `FileNotFoundException` for an existing directory, so something had recreated the path inside that window. That something is `LibreMediaConverterApp.onCreate`, which ends with appScope.launch { OutputPublisher(...).sweepStaging() } on `Dispatchers.IO`, and `sweepStaging` reads `stagingDir`, whose getter calls `mkdirs()`. Robolectric builds the application for every test that asks for one, so that background `mkdirs()` is in flight across the whole suite on a thread the paused main looper does not control and no test awaits. Retrying closes the window rather than narrowing it, because the race is not symmetric: `mkdirs()` fails on an existing regular file, so the invariant only has to survive being *established*. Once a write lands, nothing in the suite can turn this path back into a directory -- which is also why the new assertion that the sweep left a file behind is worth making. The `check()` matters as much as the loop. The next failure here should say "something recreated conversions/ as a directory", not `FileNotFoundException at line 112` -- that is the difference between a flake someone reads and a flake someone re-runs. The wider problem is #159 and is deliberately not fixed here: `AppStartSweepTest`, `JobSnapshotsTest` and `SpaceArithmeticTest` all name the same path, and the real answer is an injectable scope rather than a retry loop in every staging test. #159's done-when is that this loop can be deleted. Mutation: `listFiles() ?: return` -> `listFiles()!!` reddens exactly this test. Gate green: assembleDebug, testDebugUnitTest, compileDebugAndroidTestKotlin, ktlintCheck, detekt, lintDebug. Co-Authored-By: Claude Opus 5 (1M context) --- .../convert/OutputPublisherStagingTest.kt | 46 ++++++++++++++++++- 1 file changed, 44 insertions(+), 2 deletions(-) diff --git a/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt b/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt index a1d2365..8c39046 100644 --- a/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt +++ b/app/src/test/java/org/libremediaconverter/convert/OutputPublisherStagingTest.kt @@ -108,10 +108,46 @@ class OutputPublisherStagingTest { // cannot be a directory makes listFiles() answer null, and a sweep that dereferenced that // would take the app down on a launch rather than on a conversion -- AppStartSweepTest is // where this runs from. - File(cacheDir, "conversions").deleteRecursively() - File(cacheDir, "conversions").writeBytes(ByteArray(8)) + val stagingPath = stagingPathAsRegularFile() publisher.sweepStaging() + + assertTrue("the sweep must not have replaced the fixture", stagingPath.isFile) + } + + /** + * Makes `cacheDir/conversions` a regular file, which is the whole precondition of the test + * above -- and does it in a loop, because a single delete-then-write loses a race that CI + * caught and this machine does not reproduce. + * + * `LibreMediaConverterApp.onCreate` ends with + * `appScope.launch { OutputPublisher(...).sweepStaging() }` on `Dispatchers.IO`, and + * `sweepStaging` reads `stagingDir`, whose getter calls `mkdirs()`. Robolectric instantiates + * the application for every test that asks for one, so that background `mkdirs()` is in flight + * across the whole suite, on a thread the paused main looper does not control. Between deleting + * this path and writing it there is a window where the path does not exist and that `mkdirs()` + * can win, which is `FileNotFoundException: ... (Is a directory)` out of `writeBytes` -- run + * 33069641674 on #149, once, against 468 tests that pass here. + * + * Retrying closes it rather than narrowing it, because the race is not symmetric: `mkdirs()` + * fails on an existing regular file, so the invariant only has to survive being *established*. + * Once a write lands, nothing in the suite can turn this back into a directory. + * + * The wider problem -- application-scope IO work racing every Robolectric test that shares + * `cacheDir` -- is #159, and is deliberately not fixed here. + */ + private fun stagingPathAsRegularFile(): File { + val stagingPath = File(cacheDir, "conversions") + repeat(FIXTURE_ATTEMPTS) { + if (stagingPath.isFile) return stagingPath + stagingPath.deleteRecursively() + runCatching { stagingPath.writeBytes(ByteArray(FIXTURE_BYTES)) } + } + check(stagingPath.isFile) { + "the fixture needs $stagingPath to be a regular file and it is a directory; " + + "something recreated it $FIXTURE_ATTEMPTS times -- see #159" + } + return stagingPath } @Test @@ -125,4 +161,10 @@ class OutputPublisherStagingTest { assertFalse("a file with no parent is not in staging", publisher.discardStaged(parentless)) } + + private companion object { + /** Enough to outlast a burst of application-scope sweeps; one attempt is what CI lost. */ + const val FIXTURE_ATTEMPTS = 50 + const val FIXTURE_BYTES = 8 + } } -- 2.47.3