fix(auto-upload): allow empty files unchanged for one hour

app/src/main/java/com/nextcloud/client/jobs/autoUpload/AutoUploadWorker.kt

@@ -301,8 +301,9 @@ class AutoUploadWorker(
 
                 try {
                     // A camera app can register the file with MediaStore before it finished writing it.
-                    if (file.isFile && file.length() == 0L) {
-                        Log_OC.w(TAG, "skipping empty file, still being written: $localPath")
+                    // Allow empty files unmodified for at least one hour so intentional empty files can be uploaded.
+                    if (EmptyFileUploadPolicy.shouldDefer(file)) {
+                        Log_OC.w(TAG, "deferring empty file until unmodified for one hour: $localPath")
                         return@forEachIndexed
                     }
 

app/src/main/java/com/nextcloud/client/jobs/autoUpload/EmptyFileUploadPolicy.kt

@@ -0,0 +1,22 @@
+/*
+ * Nextcloud - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+package com.nextcloud.client.jobs.autoUpload
+
+import java.io.File
+import kotlin.time.Duration.Companion.hours
+
+internal object EmptyFileUploadPolicy {
+    private val minimumAgeMillis = 1.hours.inWholeMilliseconds
+
+    fun shouldDefer(file: File, nowMillis: Long = System.currentTimeMillis()): Boolean {
+        if (!file.isFile || file.length() != 0L) return false
+
+        val lastModified = file.lastModified()
+        return lastModified <= 0L || nowMillis - lastModified < minimumAgeMillis
+    }
+}

app/src/test/java/com/nextcloud/client/jobs/autoUpload/EmptyFileUploadPolicyTest.kt

@@ -0,0 +1,114 @@
+/*
+ * Nextcloud - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+package com.nextcloud.client.jobs.autoUpload
+
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Rule
+import org.junit.Test
+import org.junit.rules.TemporaryFolder
+import org.mockito.kotlin.doReturn
+import org.mockito.kotlin.mock
+import java.io.File
+import kotlin.time.Duration.Companion.hours
+
+class EmptyFileUploadPolicyTest {
+    @get:Rule
+    val temporaryFolder = TemporaryFolder()
+
+    private val nowMillis = 2.hours.inWholeMilliseconds
+    private val oneHourMillis = 1.hours.inWholeMilliseconds
+
+    @Test
+    fun recentEmptyFileIsDeferred() {
+        val file = emptyFile(nowMillis - oneHourMillis + 1)
+
+        assertTrue(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun emptyFileIsAllowedAtExactlyOneHour() {
+        val file = emptyFile(nowMillis - oneHourMillis)
+
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun olderEmptyFileIsAllowed() {
+        val file = emptyFile(nowMillis - oneHourMillis - 1)
+
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun modifyingAnOldEmptyFileRestartsTheGracePeriod() {
+        val file = emptyFile(nowMillis - oneHourMillis)
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+
+        assertTrue(file.setLastModified(nowMillis))
+
+        assertTrue(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun recentNonEmptyFileIsAllowed() {
+        val file = temporaryFolder.newFile().apply {
+            writeText("content")
+            assertTrue(setLastModified(nowMillis))
+        }
+
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun deferredFileIsAllowedAsSoonAsItHasContent() {
+        val file = emptyFile(nowMillis)
+        assertTrue(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+
+        file.writeText("content")
+        assertTrue(file.setLastModified(nowMillis))
+
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun emptyFileWithFutureModificationTimeIsDeferred() {
+        val file = emptyFile(nowMillis + oneHourMillis)
+
+        assertTrue(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun emptyFileWithUnknownModificationTimeIsDeferred() {
+        val file = mock<File> {
+            on { isFile } doReturn true
+            on { length() } doReturn 0L
+            on { lastModified() } doReturn 0L
+        }
+
+        assertTrue(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun missingFileIsLeftToExistingErrorHandling() {
+        val file = File(temporaryFolder.root, "missing.txt")
+
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(file, nowMillis))
+    }
+
+    @Test
+    fun directoryIsNotTreatedAsAnEmptyFile() {
+        val directory = temporaryFolder.newFolder()
+
+        assertFalse(EmptyFileUploadPolicy.shouldDefer(directory, nowMillis))
+    }
+
+    private fun emptyFile(lastModified: Long): File = temporaryFolder.newFile().apply {
+        assertTrue(setLastModified(lastModified))
+    }
+}