.gitea/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,23 @@
+---
+name: Bug report
+about: Something doesn't work the way it should
+title: ""
+labels:
+  - bug
+---
+
+### What happened
+
+
+### What you expected
+
+
+### Steps to reproduce
+1.
+2.
+3.
+
+### Environment
+- Calendula version: <!-- Settings → bottom of the screen -->
+- Android version:
+- Device:

.gitea/ISSUE_TEMPLATE/crash_report.md

@@ -0,0 +1,26 @@
+---
+name: Crash report
+about: Report a crash. Calendula can capture this for you (Settings → Report a problem, or the prompt after a crash) — it copies the report to your clipboard and prefills this form.
+title: "Crash: "
+labels:
+  - bug
+  - crash
+---
+
+<!--
+Thanks for reporting a crash in Calendula!
+
+If the app prefilled this for you, the crash report is already below — just add
+what you were doing and submit. Otherwise, paste the report from your clipboard
+into the code block. The report contains only app/Android/device versions and the
+stack trace — no personal data or calendar content.
+-->
+
+### What happened
+
+
+### Crash report
+
+```
+(paste the crash report here)
+```

.gitea/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,16 @@
+---
+name: Feature request
+about: Suggest an idea or improvement
+title: ""
+labels:
+  - enhancement
+---
+
+### What would you like Calendula to do?
+
+
+### Why — what problem does it solve?
+
+
+### Anything else
+<!-- mockups, examples from other apps, alternatives you considered -->

CHANGELOG.md

@@ -7,6 +7,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.7.1] — 2026-06-18
+
+### Added
+- Crash reporting you control. If Calendula closes unexpectedly, it now captures
+  a technical report and, on the next launch, offers to send it as an issue on
+  the project's tracker. Nothing is uploaded automatically — the report stays on
+  your device until you choose to share it, it contains no personal data or
+  calendar content (only the app, Android and device versions plus the stack
+  trace), and you see the full text before sending. There's also a "Report a
+  problem" entry in Settings, and if the app ever fails to start repeatedly, a
+  minimal recovery screen still lets you send the report.
+
 ## [2.7.0] — 2026-06-18
 
 ### Added

app/build.gradle.kts

@@ -28,8 +28,8 @@ android {
         // the tag, with versionCode = MAJOR*10000 + MINOR*100 + PATCH
         // (e.g. v2.0.0 -> 20000). These committed values are the dev/local
         // default; keep them matching the latest released tag. See docs/RELEASING.md.
-        versionCode = 20700
-        versionName = "2.7.0"
+        versionCode = 20701
+        versionName = "2.7.1"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }

app/src/main/AndroidManifest.xml

@@ -68,6 +68,15 @@
                 android:resource="@xml/shortcuts" />
         </activity>
 
+        <!-- Standalone surface for a captured crash report. MainActivity routes
+             here on a startup crash-loop, so it stays clear of the app's Hilt
+             graph and Compose content. Not exported: launched only by us. -->
+        <activity
+            android:name=".ui.crash.CrashReportActivity"
+            android:exported="false"
+            android:excludeFromRecents="true"
+            android:launchMode="singleTask" />
+
         <!-- The provider broadcasts EVENT_REMINDER at reminder time but posts
              no notification itself — a calendar app must (v1.4, Etar model).
              Exported: the broadcast arrives from the provider's process. -->

app/src/main/java/de/jeanlucmakiola/calendula/CalendulaApp.kt

@@ -2,10 +2,19 @@ package de.jeanlucmakiola.calendula
 
 import android.app.Application
 import dagger.hilt.android.HiltAndroidApp
+import de.jeanlucmakiola.calendula.data.crash.CrashReporter
 
 /**
  * Application entry point. Registered as android:name=".CalendulaApp"
  * in AndroidManifest.xml. Hilt initializes its component graph here.
  */
 @HiltAndroidApp
-class CalendulaApp : Application()
+class CalendulaApp : Application() {
+
+    override fun onCreate() {
+        super.onCreate()
+        // Install first thing so startup crashes are captured too (privacy-
+        // respecting, on-device; the user submits the report by hand).
+        CrashReporter.install(this)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt

@@ -18,9 +18,13 @@ import androidx.core.net.toUri
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.crash.CrashReporter
 import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
 import de.jeanlucmakiola.calendula.ui.RootScreen
 import de.jeanlucmakiola.calendula.ui.WidgetNavRequest
+import de.jeanlucmakiola.calendula.ui.crash.CrashReportActivity
+import de.jeanlucmakiola.calendula.ui.crash.CrashReportDialog
+import de.jeanlucmakiola.calendula.ui.crash.submitCrashReport
 import de.jeanlucmakiola.calendula.ui.settings.SettingsViewModel
 import de.jeanlucmakiola.calendula.ui.theme.CalendulaTheme
 import kotlinx.datetime.LocalDate
@@ -41,12 +45,31 @@ class MainActivity : AppCompatActivity() {
     // by CalendarHost's import flow.
     private var requestedImportUri by mutableStateOf<Uri?>(null)
 
+    // A captured crash report awaiting the user's decision, surfaced as a dialog
+    // over the calendar on the next launch (the single-crash path). A startup
+    // crash-loop is handled out of band, before setContent — see below.
+    private var pendingCrashReport by mutableStateOf<String?>(null)
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+
+        // If the app keeps crashing as it starts, the main UI can't be trusted
+        // to come up — route to the standalone report screen instead of
+        // re-entering the crashing graph.
+        if (CrashReporter.isCrashLoop(this)) {
+            startActivity(
+                Intent(this, CrashReportActivity::class.java)
+                    .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK),
+            )
+            finish()
+            return
+        }
+
         enableEdgeToEdge()
         requestedDetailKey = intent.detailKeyOrNull()
         requestedNav = intent.navRequestOrNull()
         requestedImportUri = intent.importUriOrNull()
+        if (CrashReporter.shouldPrompt(this)) pendingCrashReport = CrashReporter.pendingReport(this)
         setContent {
             // One activity-scoped SettingsViewModel drives both the theme here
             // and the Settings screen, so a theme change applies app-wide at once.
@@ -70,10 +93,32 @@ class MainActivity : AppCompatActivity() {
                     requestedImportUri = requestedImportUri,
                     onImportConsumed = { requestedImportUri = null },
                 )
+                pendingCrashReport?.let { report ->
+                    CrashReportDialog(
+                        report = report,
+                        onSend = {
+                            submitCrashReport(this@MainActivity, report)
+                            CrashReporter.clearReport(this@MainActivity)
+                            pendingCrashReport = null
+                        },
+                        onDismiss = {
+                            // Keep the report (Settings can still reach it); just
+                            // stop it popping on every launch.
+                            CrashReporter.dismissPrompt(this@MainActivity)
+                            pendingCrashReport = null
+                        },
+                    )
+                }
             }
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        // Reaching a running UI means startup succeeded; reset the loop trail.
+        CrashReporter.markHealthy(this)
+    }
+
     override fun onNewIntent(intent: Intent) {
         super.onNewIntent(intent)
         intent.detailKeyOrNull()?.let { requestedDetailKey = it }

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarDataSource.kt

@@ -204,7 +204,8 @@ class AndroidCalendarDataSource @Inject constructor(
             putDescription(description)
         }
         val uri = resolver.insert(localCalendarsUri(), values)
-            ?: throw WriteFailedException("create local calendar '$name'")
+            // No calendar name in the message — it can reach a crash report.
+            ?: throw WriteFailedException("create local calendar")
         return ContentUris.parseId(uri)
     }
 
@@ -685,7 +686,8 @@ class AndroidCalendarDataSource @Inject constructor(
                     is String -> cv.put(column, value)
                     is Long -> cv.put(column, value)
                     is Int -> cv.put(column, value)
-                    else -> error("Unsupported value for $column: $value")
+                    // Only the type, never the value — a cell value can be event content.
+                    else -> error("Unsupported value type for column '$column': ${value::class.simpleName}")
                 }
             }
         }

app/src/main/java/de/jeanlucmakiola/calendula/data/crash/CrashReporter.kt

@@ -0,0 +1,188 @@
+package de.jeanlucmakiola.calendula.data.crash
+
+import android.content.Context
+import android.content.pm.PackageInfo
+import android.os.Build
+import androidx.core.content.pm.PackageInfoCompat
+import java.io.File
+import java.io.PrintWriter
+import java.io.StringWriter
+import java.time.Instant
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.util.Locale
+
+/**
+ * Privacy-respecting crash capture (prod-readiness item 10). On an uncaught
+ * exception it writes a self-contained report to the app's private storage and
+ * then chains to the platform's default handler, so the process still dies
+ * normally (and the OS shows its own "stopped" dialog). Nothing is uploaded —
+ * the app holds no `INTERNET` permission. The user submits the report later,
+ * by hand, as a Gitea issue (see the ui/crash surfaces).
+ *
+ * The report is built from a fixed [CrashContext] allowlist — app/Android/device
+ * version, locale, time, and the stack trace — and **nothing else**: no device
+ * identifiers, no account names, no calendar/event content, no logcat. The user
+ * is always shown the full text before it leaves the device.
+ */
+object CrashReporter {
+
+    /**
+     * Install the handler. Called first thing in `CalendulaApp.onCreate()` so it
+     * also catches crashes during startup. The handler swallows nothing — it
+     * persists, then delegates to the previously-registered handler.
+     */
+    fun install(context: Context) {
+        val appContext = context.applicationContext
+        val previous = Thread.getDefaultUncaughtExceptionHandler()
+        Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
+            // Capturing must never mask the original crash, so guard every step.
+            runCatching {
+                val now = System.currentTimeMillis()
+                writeReport(appContext, buildCrashReport(CrashContext.from(appContext), throwable, now))
+                recordCrashTime(appContext, now)
+            }
+            previous?.uncaughtException(thread, throwable)
+        }
+    }
+
+    /** The persisted report from the last crash, or null if there is none. */
+    fun pendingReport(context: Context): String? {
+        val file = reportFile(context)
+        return if (file.exists()) runCatching { file.readText() }.getOrNull()?.takeIf { it.isNotBlank() } else null
+    }
+
+    /**
+     * Whether to surface the report unprompted (on the next launch): a report
+     * exists and the user hasn't already waved this one away. Settings reaches
+     * the report via [pendingReport] regardless, so "Not now" only stops the
+     * auto-prompt — it doesn't discard the report.
+     */
+    fun shouldPrompt(context: Context): Boolean =
+        reportFile(context).exists() && !dismissedFile(context).exists()
+
+    /** Stop auto-prompting for the current report without discarding it. */
+    fun dismissPrompt(context: Context) {
+        runCatching { dismissedFile(context).apply { parentFile?.mkdirs() }.writeText("") }
+    }
+
+    /** Drop the persisted report once the user has reported it (or from Settings). */
+    fun clearReport(context: Context) {
+        runCatching { reportFile(context).delete() }
+        runCatching { dismissedFile(context).delete() }
+    }
+
+    /**
+     * Whether the app appears to be in a startup crash-loop: at least
+     * [LOOP_THRESHOLD] crashes inside [LOOP_WINDOW_MS]. In that case the main UI
+     * can't be trusted to start, so the caller routes straight to the standalone
+     * report screen instead of re-entering the crashing graph.
+     */
+    fun isCrashLoop(context: Context): Boolean {
+        val times = readCrashTimes(context)
+        if (times.size < LOOP_THRESHOLD) return false
+        val recent = times.sortedDescending()
+        return recent[0] - recent[LOOP_THRESHOLD - 1] <= LOOP_WINDOW_MS
+    }
+
+    /**
+     * Mark the app as having started successfully, resetting the loop counter so
+     * an ordinary single crash much later never trips loop detection. The
+     * pending report itself is kept — only the timing trail is cleared.
+     */
+    fun markHealthy(context: Context) {
+        runCatching { timesFile(context).delete() }
+    }
+
+    // --- persistence -------------------------------------------------------
+
+    private fun writeReport(context: Context, report: String) {
+        val file = reportFile(context).apply { parentFile?.mkdirs() }
+        file.writeText(report.take(MAX_REPORT_CHARS))
+        // A fresh crash should prompt again, even if the previous one was waved away.
+        runCatching { dismissedFile(context).delete() }
+    }
+
+    private fun recordCrashTime(context: Context, nowMillis: Long) {
+        val kept = (readCrashTimes(context) + nowMillis).takeLast(MAX_TIMES)
+        timesFile(context).apply { parentFile?.mkdirs() }
+            .writeText(kept.joinToString("\n"))
+    }
+
+    private fun readCrashTimes(context: Context): List<Long> {
+        val file = timesFile(context)
+        if (!file.exists()) return emptyList()
+        return runCatching { file.readLines().mapNotNull { it.trim().toLongOrNull() } }.getOrDefault(emptyList())
+    }
+
+    private fun crashDir(context: Context) = File(context.filesDir, CRASH_DIR)
+    private fun reportFile(context: Context) = File(crashDir(context), REPORT_FILE)
+    private fun timesFile(context: Context) = File(crashDir(context), TIMES_FILE)
+    private fun dismissedFile(context: Context) = File(crashDir(context), DISMISSED_FILE)
+
+    private const val CRASH_DIR = "crash"
+    private const val REPORT_FILE = "last_crash.txt"
+    private const val TIMES_FILE = "crash_times.txt"
+    private const val DISMISSED_FILE = "dismissed"
+    private const val MAX_TIMES = 5
+    private const val MAX_REPORT_CHARS = 64 * 1024
+    private const val LOOP_THRESHOLD = 2
+    private const val LOOP_WINDOW_MS = 10_000L
+}
+
+/**
+ * The allowlist of non-personal facts that go into a crash report. Built from
+ * [Build] and the app's own [PackageInfo]; deliberately holds no identifiers.
+ */
+data class CrashContext(
+    val appVersionName: String,
+    val appVersionCode: Long,
+    val sdkInt: Int,
+    val androidRelease: String,
+    val manufacturer: String,
+    val model: String,
+    val locale: String,
+) {
+    companion object {
+        fun from(context: Context): CrashContext {
+            val pkg = runCatching {
+                context.packageManager.getPackageInfo(context.packageName, 0)
+            }.getOrNull()
+            return CrashContext(
+                appVersionName = pkg?.versionName ?: "?",
+                appVersionCode = pkg?.let { PackageInfoCompat.getLongVersionCode(it) } ?: 0L,
+                sdkInt = Build.VERSION.SDK_INT,
+                androidRelease = Build.VERSION.RELEASE ?: "?",
+                manufacturer = Build.MANUFACTURER ?: "?",
+                model = Build.MODEL ?: "?",
+                locale = Locale.getDefault().toLanguageTag(),
+            )
+        }
+    }
+}
+
+/**
+ * Render a crash report from the [ctx] allowlist, the [throwable]'s full stack
+ * trace, and the crash [nowMillis]. Pure (no Android, no I/O) so it is unit
+ * tested. The leading marker doubles as the file's sanity check in
+ * [CrashReporter.pendingReport].
+ */
+fun buildCrashReport(ctx: CrashContext, throwable: Throwable, nowMillis: Long): String {
+    val trace = StringWriter().also { throwable.printStackTrace(PrintWriter(it)) }.toString().trim()
+    val time = runCatching {
+        Instant.ofEpochMilli(nowMillis).atZone(ZoneId.systemDefault()).format(TIME_FORMAT)
+    }.getOrDefault(nowMillis.toString())
+    return buildString {
+        appendLine("Calendula crash report")
+        appendLine("App version: ${ctx.appVersionName} (${ctx.appVersionCode})")
+        appendLine("Android: ${ctx.androidRelease} (API ${ctx.sdkInt})")
+        appendLine("Device: ${ctx.manufacturer} ${ctx.model}")
+        appendLine("Locale: ${ctx.locale}")
+        appendLine("Time: $time")
+        appendLine()
+        appendLine("Stack trace:")
+        append(trace)
+    }
+}
+
+private val TIME_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")

app/src/main/java/de/jeanlucmakiola/calendula/data/ics/IcsExporter.kt

@@ -24,7 +24,8 @@ class IcsExporter @Inject constructor(
     fun writeDocument(uri: Uri, content: String) {
         context.contentResolver.openOutputStream(uri)?.use { out ->
             out.write(content.toByteArray(Charsets.UTF_8))
-        } ?: throw IOException("Could not open $uri for writing")
+            // Only the scheme — the full Uri can embed the user's chosen filename.
+        } ?: throw IOException("Could not open output stream for export (scheme=${uri.scheme})")
     }
 
     /**

app/src/main/java/de/jeanlucmakiola/calendula/ui/crash/CrashReportActivity.kt

@@ -0,0 +1,59 @@
+package de.jeanlucmakiola.calendula.ui.crash
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.ui.Modifier
+import de.jeanlucmakiola.calendula.data.crash.CrashReporter
+import de.jeanlucmakiola.calendula.ui.theme.CalendulaTheme
+
+/**
+ * A deliberately minimal, standalone surface for a captured crash report.
+ * `MainActivity` routes here when it detects a startup crash-loop (see
+ * [CrashReporter.isCrashLoop]): the main UI can't be trusted to start, so this
+ * screen stays clear of the app's Hilt graph, DataStore-backed theme and
+ * Compose content — it only reads the report file and shows the report dialog.
+ * Plain [CalendulaTheme] defaults (follow-system, dynamic colour) avoid touching
+ * anything that might be the cause of the crash.
+ */
+class CrashReportActivity : ComponentActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val report = CrashReporter.pendingReport(this)
+        if (report == null) {
+            finish()
+            return
+        }
+        enableEdgeToEdge()
+        setContent {
+            CalendulaTheme {
+                // Opaque backdrop so the dialog doesn't float over a bare task.
+                Surface(Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.surface) {}
+                CrashReportDialog(
+                    report = report,
+                    onSend = {
+                        submitCrashReport(this, report)
+                        CrashReporter.clearReport(this)
+                        finish()
+                    },
+                    onDismiss = {
+                        CrashReporter.clearReport(this)
+                        finish()
+                    },
+                )
+            }
+        }
+    }
+
+    override fun onResume() {
+        super.onResume()
+        // Reaching this screen breaks the loop; reset the timing trail so a
+        // later ordinary crash isn't mistaken for a loop.
+        CrashReporter.markHealthy(this)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/crash/CrashReportDialog.kt

@@ -0,0 +1,75 @@
+package de.jeanlucmakiola.calendula.ui.crash
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.BugReport
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * Asks the user to send a captured crash report as an issue. The full report is
+ * shown verbatim in a scrollable panel — the user sees exactly what will leave
+ * the device before choosing to share it (the privacy backstop). [onSend] hands
+ * off to [submitCrashReport]; [onDismiss] declines.
+ */
+@Composable
+fun CrashReportDialog(
+    report: String,
+    onSend: () -> Unit,
+    onDismiss: () -> Unit,
+) {
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        icon = { Icon(Icons.Default.BugReport, contentDescription = null) },
+        title = { Text(stringResource(R.string.crash_dialog_title)) },
+        text = {
+            Column {
+                Text(
+                    text = stringResource(R.string.crash_dialog_message),
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+                Spacer(Modifier.height(12.dp))
+                Surface(
+                    color = MaterialTheme.colorScheme.surfaceContainerHighest,
+                    shape = RoundedCornerShape(12.dp),
+                    modifier = Modifier.fillMaxWidth(),
+                ) {
+                    Text(
+                        text = report,
+                        style = MaterialTheme.typography.bodySmall,
+                        fontFamily = FontFamily.Monospace,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier
+                            .heightIn(max = 220.dp)
+                            .verticalScroll(rememberScrollState())
+                            .padding(12.dp),
+                    )
+                }
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = onSend) { Text(stringResource(R.string.crash_dialog_report)) }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.crash_dialog_dismiss)) }
+        },
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/crash/CrashReportSubmit.kt

@@ -0,0 +1,61 @@
+package de.jeanlucmakiola.calendula.ui.crash
+
+import android.content.ClipData
+import android.content.ClipboardManager
+import android.content.Context
+import android.content.Intent
+import android.widget.Toast
+import androidx.core.net.toUri
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * Hand the captured crash report off to the user's chosen channel: the report
+ * is copied to the clipboard (the reliable path for a full stack trace) and the
+ * project's Gitea "new issue" page is opened with the body prefilled. Nothing is
+ * sent automatically — the app has no network access; the user reviews and
+ * submits the issue themselves.
+ */
+fun submitCrashReport(context: Context, report: String) {
+    copyReportToClipboard(context, report)
+    val opened = runCatching {
+        context.startActivity(Intent(Intent.ACTION_VIEW, buildIssueUri(context, report)))
+    }.isSuccess
+    val message = if (opened) R.string.crash_report_copied else R.string.crash_report_open_failed
+    Toast.makeText(context, message, Toast.LENGTH_LONG).show()
+}
+
+/** Open the issue tracker's template chooser for a manual (non-crash) report. */
+fun openIssueTracker(context: Context) {
+    val uri = context.getString(R.string.report_issue_choose_url).toUri()
+    runCatching { context.startActivity(Intent(Intent.ACTION_VIEW, uri)) }
+}
+
+private fun copyReportToClipboard(context: Context, report: String) {
+    val clipboard = context.getSystemService(Context.CLIPBOARD_SERVICE) as? ClipboardManager ?: return
+    val label = context.getString(R.string.crash_report_clip_label)
+    clipboard.setPrimaryClip(ClipData.newPlainText(label, report))
+}
+
+/**
+ * The Gitea `issues/new` URL with `title` and `body` prefilled. A full report
+ * can blow past URL-length limits, so an over-long one is left out of the link
+ * (with a "paste from clipboard" placeholder) — the clipboard copy is the
+ * source of truth in that case.
+ */
+private fun buildIssueUri(context: Context, report: String) =
+    context.getString(R.string.report_issue_url).toUri().buildUpon()
+        .appendQueryParameter("title", context.getString(R.string.crash_report_issue_title))
+        .appendQueryParameter("body", buildIssueBody(context, report))
+        .build()
+
+private fun buildIssueBody(context: Context, report: String): String {
+    val block = if (report.length > MAX_URL_REPORT_CHARS) {
+        context.getString(R.string.crash_report_body_paste)
+    } else {
+        "```\n$report\n```"
+    }
+    return context.getString(R.string.crash_report_body_template, block)
+}
+
+/** Keep the prefilled body comfortably under common URL-length ceilings. */
+private const val MAX_URL_REPORT_CHARS = 6_000

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsScreen.kt

@@ -33,6 +33,7 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.BugReport
 import androidx.compose.material.icons.filled.CalendarMonth
 import androidx.compose.material.icons.filled.Check
 import androidx.compose.material.icons.filled.ExpandLess
@@ -73,10 +74,14 @@ import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.crash.CrashReporter
 import de.jeanlucmakiola.calendula.data.prefs.CalendarReminderOverride
 import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
 import de.jeanlucmakiola.calendula.data.prefs.WeekStartPref
 import de.jeanlucmakiola.calendula.domain.EventFormField
+import de.jeanlucmakiola.calendula.ui.crash.CrashReportDialog
+import de.jeanlucmakiola.calendula.ui.crash.openIssueTracker
+import de.jeanlucmakiola.calendula.ui.crash.submitCrashReport
 import de.jeanlucmakiola.calendula.ui.common.CollapsingScaffold
 import de.jeanlucmakiola.calendula.ui.common.GroupedRow
 import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
@@ -196,12 +201,48 @@ private fun SettingsHub(
             leading = { CategoryIcon(Icons.Default.CalendarMonth, ChipAccent.Tertiary) },
             onClick = onManageCalendars,
         )
-        LanguageRow(position = Position.Bottom)
+        LanguageRow(position = Position.Middle)
+        ReportProblemRow(position = Position.Bottom)
 
         AppVersionText()
     }
 }
 
+/**
+ * Opens the project's issue tracker to report a problem. If a crash report was
+ * captured (and not yet sent), it surfaces that report first via the same
+ * dialog the next-launch prompt uses; otherwise it opens the issue template
+ * chooser. No data leaves the device until the user submits the issue.
+ */
+@Composable
+private fun ReportProblemRow(position: Position) {
+    val context = LocalContext.current
+    var report by remember { mutableStateOf<String?>(null) }
+
+    GroupedRow(
+        title = stringResource(R.string.settings_report_problem),
+        summary = stringResource(R.string.settings_report_problem_hint),
+        position = position,
+        leading = { CategoryIcon(Icons.Default.BugReport, ChipAccent.Neutral) },
+        onClick = {
+            val pending = CrashReporter.pendingReport(context)
+            if (pending != null) report = pending else openIssueTracker(context)
+        },
+    )
+
+    report?.let { pending ->
+        CrashReportDialog(
+            report = pending,
+            onSend = {
+                submitCrashReport(context, pending)
+                CrashReporter.clearReport(context)
+                report = null
+            },
+            onDismiss = { report = null },
+        )
+    }
+}
+
 @Composable
 private fun LanguageRow(position: Position) {
     val context = LocalContext.current

app/src/main/res/values-de/strings.xml

@@ -282,6 +282,8 @@
     <string name="settings_about_source">Quellcode</string>
     <string name="settings_about_version">Version %1$s</string>
     <string name="settings_about_logo_desc">Calendula-App-Symbol</string>
+    <string name="settings_report_problem">Problem melden</string>
+    <string name="settings_report_problem_hint">Absturzbericht senden oder Issue-Tracker öffnen</string>
 
     <!-- Calendar manager -->
     <string name="calendars_title">Kalender</string>
@@ -337,4 +339,16 @@
         <item quantity="one">%d bereits in diesem Kalender übersprungen.</item>
         <item quantity="other">%d bereits in diesem Kalender übersprungen.</item>
     </plurals>
+
+    <!-- Absturzberichte: vom Nutzer selbst als Gitea-Issue einreichbar -->
+    <string name="crash_dialog_title">Calendula ist abgestürzt</string>
+    <string name="crash_dialog_message">Calendula wurde beim letzten Mal unerwartet beendet. Du kannst bei der Behebung helfen, indem du diesen Bericht als Issue sendest. Er bleibt auf deinem Gerät, bis du ihn teilst, und enthält keine persönlichen Daten oder Kalenderinhalte — nur die technischen Angaben unten.</string>
+    <string name="crash_dialog_report">Melden</string>
+    <string name="crash_dialog_dismiss">Nicht jetzt</string>
+    <string name="crash_report_issue_title">Absturzbericht</string>
+    <string name="crash_report_clip_label">Calendula-Absturzbericht</string>
+    <string name="crash_report_copied">Bericht in die Zwischenablage kopiert</string>
+    <string name="crash_report_open_failed">Der Issue-Tracker konnte nicht geöffnet werden. Der Bericht ist in deiner Zwischenablage.</string>
+    <string name="crash_report_body_template">Danke, dass du einen Absturz in Calendula meldest. Bitte ergänze, was du gerade getan hast, und sende dann ab.\n\n### Was ist passiert\n\n\n### Absturzbericht\n%1$s\n</string>
+    <string name="crash_report_body_paste">_(Der Bericht war zu lang für diesen Link — füge ihn aus deiner Zwischenablage hier ein.)_</string>
 </resources>

app/src/main/res/values/strings.xml

@@ -279,6 +279,8 @@
     <string name="settings_about_source">Source</string>
     <string name="settings_about_version">Version %1$s</string>
     <string name="settings_about_logo_desc">Calendula app icon</string>
+    <string name="settings_report_problem">Report a problem</string>
+    <string name="settings_report_problem_hint">Send a crash report or open the issue tracker</string>
 
     <!-- Calendar manager -->
     <string name="calendars_title">Calendars</string>
@@ -340,4 +342,19 @@
 
     <string name="about_source_url" translatable="false">https://gitea.jeanlucmakiola.de/makiolaj/calendula</string>
     <string name="about_license_url" translatable="false">https://gitea.jeanlucmakiola.de/makiolaj/calendula/src/branch/main/LICENSE</string>
+
+    <!-- Crash reporting: a captured report the user can submit, by hand, as a
+         Gitea issue (the app sends nothing automatically). -->
+    <string name="crash_dialog_title">Calendula crashed</string>
+    <string name="crash_dialog_message">Calendula closed unexpectedly last time. You can help fix it by sending this report as an issue. It stays on your device until you choose to share it, and includes no personal data or calendar content — only the technical details below.</string>
+    <string name="crash_dialog_report">Report</string>
+    <string name="crash_dialog_dismiss">Not now</string>
+    <string name="crash_report_issue_title">Crash report</string>
+    <string name="crash_report_clip_label">Calendula crash report</string>
+    <string name="crash_report_copied">Report copied to your clipboard</string>
+    <string name="crash_report_open_failed">Couldn\'t open the issue tracker. The report is on your clipboard.</string>
+    <string name="crash_report_body_template">Thanks for reporting a crash in Calendula. Please add anything you remember about what you were doing, then submit.\n\n### What happened\n\n\n### Crash report\n%1$s\n</string>
+    <string name="crash_report_body_paste">_(The report was too long for this link — paste it from your clipboard here.)_</string>
+    <string name="report_issue_url" translatable="false">https://gitea.jeanlucmakiola.de/makiolaj/calendula/issues/new</string>
+    <string name="report_issue_choose_url" translatable="false">https://gitea.jeanlucmakiola.de/makiolaj/calendula/issues/new/choose</string>
 </resources>

app/src/test/java/de/jeanlucmakiola/calendula/data/crash/CrashReportBuilderTest.kt

@@ -0,0 +1,56 @@
+package de.jeanlucmakiola.calendula.data.crash
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class CrashReportBuilderTest {
+
+    private val context = CrashContext(
+        appVersionName = "2.7.0",
+        appVersionCode = 20700,
+        sdkInt = 34,
+        androidRelease = "14",
+        manufacturer = "Google",
+        model = "Pixel 7",
+        locale = "en-DE",
+    )
+
+    @Test
+    fun `report carries the allowlisted facts and the stack trace`() {
+        val report = buildCrashReport(context, IllegalStateException("boom"), nowMillis = 0L)
+
+        assertThat(report).startsWith("Calendula crash report")
+        assertThat(report).contains("App version: 2.7.0 (20700)")
+        assertThat(report).contains("Android: 14 (API 34)")
+        assertThat(report).contains("Device: Google Pixel 7")
+        assertThat(report).contains("Locale: en-DE")
+        // The exception type + message and a frame from this test are present.
+        assertThat(report).contains("IllegalStateException")
+        assertThat(report).contains("boom")
+        assertThat(report).contains("CrashReportBuilderTest")
+    }
+
+    @Test
+    fun `nested causes are included`() {
+        val cause = NullPointerException("inner")
+        val report = buildCrashReport(context, RuntimeException("outer", cause), nowMillis = 0L)
+
+        assertThat(report).contains("outer")
+        assertThat(report).contains("Caused by")
+        assertThat(report).contains("inner")
+    }
+
+    @Test
+    fun `report holds only the allowlisted lines before the stack trace`() {
+        val report = buildCrashReport(context, Exception("x"), nowMillis = 0L)
+        val header = report.substringBefore("Stack trace:").trim().lines()
+
+        // No identifiers, accounts, or extra fields ever creep into the header:
+        // it is exactly the six allowlisted lines plus the title.
+        assertThat(header).hasSize(6)
+        assertThat(header.first()).isEqualTo("Calendula crash report")
+        assertThat(header.map { it.substringBefore(":") }).containsExactly(
+            "Calendula crash report", "App version", "Android", "Device", "Locale", "Time",
+        ).inOrder()
+    }
+}