From ab456541924dcb1e1c6d6c7ba1781011e3453f27 Mon Sep 17 00:00:00 2001
From: David Bremner <david@tethera.net>
Date: Tue, 14 Jul 2020 19:31:10 -0300
Subject: [PATCH 1/1] lib/n_d_get_version: catch exceptions and clarify the API

notmuch_database_get_version previously returned 0 on some errors, but
did not document this. Luckily 0 is not a valid database version.
---
 lib/database.cc           | 19 ++++++++++++++++++-
 lib/notmuch.h             |  3 +++
 test/T562-lib-database.sh |  5 +++--
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/lib/database.cc b/lib/database.cc
index cfb19ccb..8ec91987 100644
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -58,6 +58,17 @@ typedef struct {
 #define DB_ACTION Xapian::DB_CREATE_OR_OPEN
 #endif
 
+#define LOG_XAPIAN_EXCEPTION(message, error) _log_xapian_exception (__location__, message, error)
+
+static void
+_log_xapian_exception (const char *where, notmuch_database_t *notmuch,  const Xapian::Error error) {
+    _notmuch_database_log (notmuch,
+			   "A Xapian exception occurred at %s: %s\n",
+			   where,
+			   error.get_msg ().c_str ());
+    notmuch->exception_reported = true;
+}
+
 /* Here's the current schema for our database (for NOTMUCH_DATABASE_VERSION):
  *
  * We currently have three different types of documents (mail, ghost,
@@ -1360,7 +1371,13 @@ notmuch_database_get_version (notmuch_database_t *notmuch)
     const char *str;
     char *end;
 
-    version_string = notmuch->xapian_db->get_metadata ("version");
+    try {
+	version_string = notmuch->xapian_db->get_metadata ("version");
+    } catch (const Xapian::Error &error) {
+	LOG_XAPIAN_EXCEPTION (notmuch, error);
+	return 0;
+    }
+
     if (version_string.empty ())
 	return 0;
 
diff --git a/lib/notmuch.h b/lib/notmuch.h
index 0dd442d4..d9f3003f 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -431,6 +431,8 @@ notmuch_database_get_path (notmuch_database_t *database);
 
 /**
  * Return the database format version of the given database.
+ *
+ * @retval 0 on error
  */
 unsigned int
 notmuch_database_get_version (notmuch_database_t *database);
@@ -444,6 +446,7 @@ notmuch_database_get_version (notmuch_database_t *database);
  * fail with NOTMUCH_STATUS_UPGRADE_REQUIRED.  This always returns
  * FALSE for a read-only database because there's no way to upgrade a
  * read-only database.
+ *
  */
 notmuch_bool_t
 notmuch_database_needs_upgrade (notmuch_database_t *database);
diff --git a/test/T562-lib-database.sh b/test/T562-lib-database.sh
index b8fba7d6..20bed8b4 100755
--- a/test/T562-lib-database.sh
+++ b/test/T562-lib-database.sh
@@ -15,7 +15,7 @@ cat <<EOF > c_head
 int main (int argc, char** argv)
 {
    notmuch_database_t *db;
-   notmuch_status_t stat;
+   notmuch_status_t stat = NOTMUCH_STATUS_SUCCESS;
    char *msg = NULL;
 
    stat = notmuch_database_open_verbose (argv[1], NOTMUCH_DATABASE_MODE_READ_WRITE, &db, &msg);
@@ -68,19 +68,20 @@ EOF
 test_expect_equal_file EXPECTED OUTPUT
 
 test_begin_subtest "get version with closed db"
-test_subtest_known_broken
 cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
     {
         unsigned int version;
         EXPECT0(notmuch_database_close (db));
         version = notmuch_database_get_version (db);
         printf ("%u\n", version);
+        stat = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
     }
 EOF
 cat <<EOF > EXPECTED
 == stdout ==
 0
 == stderr ==
+A Xapian exception occurred at lib/database.cc:XXX: Database has been closed
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
-- 
2.43.0