Name each database target's archive for its webhook and target (closes #376)

Each database target now writes its own archive file, archive-WEBHOOKNAME-TARGETNAME-TARGETID.db, named by delivery.ArchiveFileName, in place of one archive per webhook keyed on its UUID. Renaming a webhook or a target renames its archive files (with any -wal and -shm) before the new name is saved, never over an existing file, and moves every one back if a rename or the save fails. The webhook edit, the target edit and target creation share one lock so no two interleave. Deleting a webhook or target leaves its files on disk. Nothing looks for the old archive-WEBHOOKID.db files. The README gives the naming and the recovery steps.

Model: opus-5-5

internal/handlers/target_edit_test.go

@@ -635,3 +635,100 @@ func assertWebhookOfAnotherUser404s(
 
 	assert.Equal(t, http.StatusNotFound, w.Code)
 }
+
+// renamedTargetName is the name the rename tests give a target.
+const renamedTargetName = "Long Term"
+
+// TestHandleTargetEditSubmit_RenamesArchive proves that renaming a
+// database target renames its archive, that a save that keeps the
+// name renames nothing, that a target of another type has no archive
+// to rename, and that a target whose archive cannot be renamed keeps
+// its stored name. When a file already has the archive's new name,
+// the edit is refused with an error naming that file.
+func TestHandleTargetEditSubmit_RenamesArchive(t *testing.T) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhookWithRetention(t, env.db, 7)
+	archive := seedTarget(t, env.db, wh.ID, database.TargetTypeDatabase)
+	rename := url.Values{"name": {renamedTargetName}}
+
+	w := submitTargetEdit(env, wh.ID, archive.ID, rename)
+	require.Equal(t, http.StatusSeeOther, w.Code, w.Body.String())
+	assert.Equal(
+		t,
+		[]archiveRename{{archive.ID, wh.Name, renamedTargetName}},
+		env.archives.Renames(),
+	)
+
+	w = submitTargetEdit(env, wh.ID, archive.ID, rename)
+	require.Equal(t, http.StatusSeeOther, w.Code, w.Body.String())
+	assert.Len(
+		t, env.archives.Renames(), 1,
+		"a save that keeps the name renames nothing",
+	)
+
+	httpWebhook, httpTarget := seedHTTPTarget(t, env, "", "")
+
+	w = submitTargetEdit(
+		env, httpWebhook.ID, httpTarget.ID,
+		editForm(editOriginalURL, "", ""),
+	)
+	require.Equal(t, http.StatusSeeOther, w.Code, w.Body.String())
+	assert.Len(
+		t, env.archives.Renames(), 1,
+		"an HTTP target has no archive to rename",
+	)
+
+	again := url.Values{"name": {"Again"}}
+
+	env.archives.FailRenames(archive.ID, errInjectedRename)
+
+	w = submitTargetEdit(env, wh.ID, archive.ID, again)
+	require.Equal(t, http.StatusInternalServerError, w.Code)
+	assert.Equal(
+		t, renamedTargetName, storedTarget(t, env, archive.ID).Name,
+		"a target whose archive was not renamed keeps its name",
+	)
+
+	env.archives.FailRenames(archive.ID, errNameTaken)
+
+	w = submitTargetEdit(env, wh.ID, archive.ID, again)
+	require.Equal(t, http.StatusConflict, w.Code)
+	assert.Contains(t, w.Body.String(), "archive-taken.db")
+	assert.Equal(
+		t, renamedTargetName, storedTarget(t, env, archive.ID).Name,
+	)
+}
+
+// TestHandleTargetEditSubmit_FailedSaveRenamesBack proves that when a
+// database target's archive is renamed but the new name cannot be
+// saved, the archive is renamed back to the stored name and the
+// stored name stays.
+func TestHandleTargetEditSubmit_FailedSaveRenamesBack(t *testing.T) {
+	t.Parallel()
+
+	env := setupSourceTest(t)
+	wh := seedWebhookWithRetention(t, env.db, 7)
+	archive := seedTarget(t, env.db, wh.ID, database.TargetTypeDatabase)
+
+	failSaveOnTable(t, env.db, "targets")
+
+	form := url.Values{}
+	form.Set("name", renamedTargetName)
+
+	w := submitTargetEdit(env, wh.ID, archive.ID, form)
+	require.Equal(t, http.StatusInternalServerError, w.Code)
+	assert.Equal(
+		t, archive.Name, storedTarget(t, env, archive.ID).Name,
+	)
+
+	assert.Equal(
+		t,
+		[]archiveRename{
+			{archive.ID, wh.Name, renamedTargetName},
+			{archive.ID, wh.Name, archive.Name},
+		},
+		env.archives.Renames(),
+	)
+}