store: use Result<Store> builder, add auto upgrade

Make it a Result type, and add auto-upgrade (not enabled yet)
Update dependents.

mu/mu-cmd-server.cc

@@ -116,16 +116,17 @@ report_error(const Mu::Error& err) noexcept
 MuError
 Mu::mu_cmd_server(const MuConfig* opts, GError** err)
 try {
-	Store  store{mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB), false /*writable*/};
-	Server server{store, output_sexp_stdout};
+	auto store = Store::make(mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB),			 Store::Options::Writable);
+	if (!store)
+		throw store.error();
 
+	Server server{*store, output_sexp_stdout};
 	g_message("created server with store @ %s; maildir @ %s; debug-mode %s",
-		  store.properties().database_path.c_str(),
-		  store.properties().root_maildir.c_str(),
+		  store->properties().database_path.c_str(),
+		  store->properties().root_maildir.c_str(),
 		  opts->debug ? "yes" : "no");
 
 	tty = ::isatty(::fileno(stdout));
-
 	const auto eval = std::string{opts->commands ? "(help :full t)"
 				      : opts->eval   ? opts->eval
 						     : ""};

mu/mu-cmd.cc

@@ -549,9 +549,13 @@ cmd_init(const MuConfig* opts, GError** err)
 		++addrs;
 	}
 
-	Mu::Store store(mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB), opts->maildir, my_addrs, conf);
+	auto store = Store::make_new(mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB),
+				     opts->maildir, my_addrs, conf);
+	if (!store)
+		throw store.error();
+
 	if (!opts->quiet) {
-		cmd_info(store, opts, NULL);
+		cmd_info(*store, opts, NULL);
 		std::cout << "\nstore created; use the 'index' command to fill/update it.\n";
 	}
 
@@ -561,9 +565,11 @@ cmd_init(const MuConfig* opts, GError** err)
 static Result<void>
 cmd_find(const MuConfig* opts)
 {
-	Mu::Store store{mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB), true /*readonly*/};
-
-	return mu_cmd_find(store, opts);
+	auto store{Store::make(mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB))};
+	if (!store)
+		return Err(store.error());
+	else
+		return mu_cmd_find(*store, opts);
 }
 
 static void
@@ -582,15 +588,22 @@ typedef MuError (*writable_store_func)(Mu::Store&, const MuConfig*, GError** err
 static MuError
 with_readonly_store(readonly_store_func func, const MuConfig* opts, GError** err)
 {
-	const Mu::Store store{mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB), true /*readonly*/};
-	return func(store, opts, err);
+	auto store{Store::make(mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB))};
+	if (!store)
+		throw store.error();
+
+	return func(*store, opts, err);
 }
 
 static MuError
 with_writable_store(writable_store_func func, const MuConfig* opts, GError** err)
 {
-	Mu::Store store{mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB), false /*!readonly*/};
-	return func(store, opts, err);
+	auto store{Store::make(mu_runtime_path(MU_RUNTIME_PATH_XAPIANDB),
+			       Store::Options::Writable)};
+	if (!store)
+		throw store.error();
+
+	return func(*store, opts, err);
 }
 
 static gboolean

mu/tests/test-mu-query.cc

@@ -32,6 +32,7 @@
 
 #include "test-mu-common.hh"
 #include "mu-query.hh"
+#include "utils/mu-result.hh"
 #include "utils/mu-str.h"
 #include "utils/mu-utils.hh"
 #include "mu-store.hh"
@@ -90,7 +91,8 @@ run_and_count_matches(const std::string& xpath,
 		      const std::string& expr,
 		      Mu::QueryFlags     flags = Mu::QueryFlags::None)
 {
-	Mu::Store store{xpath};
+	auto store{Store::make(xpath)};
+	assert_valid_result(store);
 
 	// if (g_test_verbose()) {
 	//	std::cout << "==> mquery: " << store.parse_query(expr, false) << "\n";
@@ -99,7 +101,7 @@ run_and_count_matches(const std::string& xpath,
 
 	Mu::allow_warnings();
 
-	auto qres{store.run_query(expr, {}, flags)};
+	auto qres{store->run_query(expr, {}, flags)};
 	g_assert_true(!!qres);
 	assert_no_dups(*qres);
 
@@ -237,11 +239,10 @@ test_mu_query_logic(void)
 static void
 test_mu_query_accented_chars_01(void)
 {
-	return;
+	auto store = Store::make(DB_PATH1);
+	assert_valid_result(store);
 
-	Store store{DB_PATH1};
-
-	auto qres{store.run_query("fünkÿ")};
+	auto qres{store->run_query("fünkÿ")};
 	g_assert_true(!!qres);
 	g_assert_false(qres->empty());
 
@@ -252,10 +253,6 @@ test_mu_query_accented_chars_01(void)
 	}
 
 	assert_equal(msg->subject(), "Greetings from Lothlórien");
-	const auto summ{to_string_opt_gchar(
-			mu_str_summarize(msg->body_text().value_or("").c_str(), 5))};
-	g_assert_true(!!summ);
-	assert_equal(*summ,  "Let's write some fünkÿ text using umlauts. Foo.");
 }
 
 static void