Only select existing columns in instance database migration and make form and instance migrations follow recommended patterns

collect_app/src/androidTest/java/org/odk/collect/android/database/helpers/InstancesDatabaseHelperTest.java

@@ -0,0 +1,96 @@
+package org.odk.collect.android.database.helpers;
+
+import android.content.res.AssetManager;
+import android.database.sqlite.SQLiteDatabase;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.odk.collect.android.application.Collect;
+import org.odk.collect.android.utilities.FileUtils;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.is;
+
+@RunWith(Parameterized.class)
+public class InstancesDatabaseHelperTest {
+    @Parameterized.Parameter
+    public String description;
+
+    @Parameterized.Parameter(1)
+    public String dbFilename;
+
+    @Parameterized.Parameters(name = "{0}")
+    public static Iterable<Object[]> data() {
+        return Arrays.asList(new Object[][] {
+                {"Downgrading from version with extra column drops that column", "instances_v7000_added_fakeColumn.db"},
+                {"Downgrading from version with missing column adds that column", "instances_v7000_removed_jrVersion.db"},
+
+                {"Upgrading from version with extra column drops that column", "instances_v4_real.db"},
+                {"Upgrading from version with missing column adds that column", "instances_v4_removed_jrVersion.db"}
+        });
+    }
+
+    private static final String DATABASE_PATH = Collect.METADATA_PATH + File.separator + InstancesDatabaseHelper.DATABASE_NAME;
+    private static final String TEMPORARY_EXTENSION = ".real";
+
+    @Before
+    public void saveRealDb() {
+        FileUtils.copyFile(new File(DATABASE_PATH), new File(DATABASE_PATH + TEMPORARY_EXTENSION));
+    }
+
+    @After
+    public void restoreRealDb() {
+        FileUtils.copyFile(new File(DATABASE_PATH + TEMPORARY_EXTENSION), new File(DATABASE_PATH));
+    }
+
+    @Test
+    public void testMigration() throws IOException {
+        writeDatabaseFile("database" + File.separator + dbFilename);
+        InstancesDatabaseHelper databaseHelper = new InstancesDatabaseHelper();
+        ensureMigrationAppliesFully(databaseHelper);
+
+        SQLiteDatabase db = databaseHelper.getReadableDatabase();
+        assertThat(db.getVersion(), is(InstancesDatabaseHelper.DATABASE_VERSION));
+
+        List<String> newColumnNames = InstancesDatabaseHelper.getInstancesColumnNames(db);
+
+        assertThat(newColumnNames, contains(InstancesDatabaseHelper.CURRENT_VERSION_COLUMN_NAMES));
+    }
+
+    private void writeDatabaseFile(String dbPath) throws IOException {
+        AssetManager assetManager = InstrumentationRegistry.getInstrumentation().getContext().getAssets();
+        try (InputStream input = assetManager.open(dbPath);
+             OutputStream output = new FileOutputStream(DATABASE_PATH)) {
+            byte[] buffer = new byte[1024];
+            int length;
+            while ((length = input.read(buffer)) != -1) {
+                output.write(buffer, 0, length);
+            }
+        }
+    }
+
+    /**
+     * Gets a read-only reference to the instances database and then immediately releases it.
+     *
+     * Without this, it appears that the migrations only get partially applied. It's not clear how
+     * this is possible since calls to onDowngrade and onUpgrade are wrapped in transactions. See
+     * discussion at https://github.com/opendatakit/collect/pull/3250#issuecomment-516439704
+     */
+    private void ensureMigrationAppliesFully(InstancesDatabaseHelper databaseHelper) {
+        databaseHelper.getReadableDatabase().close();
+    }
+}

collect_app/src/main/java/org/odk/collect/android/activities/FormEntryActivity.java

@@ -2512,7 +2512,7 @@ public void savingComplete(SaveResult saveResult) {
                 String message;
                 formController.getAuditEventLogger().logEvent(AuditEvent.AuditEventType.SAVE_ERROR, true);
                 if (saveResult.getSaveErrorMessage() != null) {
-                    message = getString(R.string.data_saved_error) + ": "
+                    message = getString(R.string.data_saved_error) + " "
                             + saveResult.getSaveErrorMessage();
                 } else {
                     message = getString(R.string.data_saved_error);