[PATCH 5/5] lib/load_config: document expectations for db on error, add tests

[David Bremner <david@tethera.net>]

This is a bit different than n_d_{open,create}_with_config, since
there are several non-zero status codes where we do want to return a
non-NULL database structure.
---
 lib/notmuch.h          |  2 ++
 lib/open.cc            |  7 +++++++
 test/T590-libconfig.sh | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/lib/notmuch.h b/lib/notmuch.h
index 571b8a87..64f71280 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -458,6 +458,8 @@ notmuch_database_open_with_config (const char *database_path,
  *
  * For description of arguments, @see notmuch_database_open_with_config
  *
+ * For fatal errors, database is set to NULL.
+ *
  * @retval NOTMUCH_STATUS_SUCCESS: Successfully loaded configuration.
  *
  * @retval NOTMUCH_STATUS_NO_CONFIG: No config file was loaded. Not fatal.
diff --git a/lib/open.cc b/lib/open.cc
index 6fa00a84..ba32c2f1 100644
--- a/lib/open.cc
+++ b/lib/open.cc
@@ -871,6 +871,13 @@ notmuch_database_load_config (const char *database_path,
     if (status_string)
 	*status_string = message;
 
+    if (status &&
+	status != NOTMUCH_STATUS_NO_DATABASE
+	&& status != NOTMUCH_STATUS_NO_CONFIG) {
+	notmuch_database_destroy (notmuch);
+	notmuch = NULL;
+    }
+
     if (database)
 	*database = notmuch;
 
diff --git a/test/T590-libconfig.sh b/test/T590-libconfig.sh
index cd7d6e24..e8fbd3d7 100755
--- a/test/T590-libconfig.sh
+++ b/test/T590-libconfig.sh
@@ -932,4 +932,44 @@ db == NULL: 1
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
+test_begin_subtest "load_config: database set non-null on missing config"
+test_C ${MAIL_DIR} "/nonexistent" <<EOF
+#include <notmuch-test.h>
+int main (int argc, char **argv) {
+  notmuch_status_t stat;
+  notmuch_database_t *db = NULL;
+
+  notmuch_status_t st = notmuch_database_load_config(argv[1],argv[2], NULL, &db, NULL);
+  printf("db == NULL: %d\n", db == NULL);
+}
+EOF
+cat <<EOF> EXPECTED
+== stdout ==
+db == NULL: 0
+== stderr ==
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+test_begin_subtest "load_config: database non-null on missing config (env)"
+old_NOTMUCH_CONFIG=${NOTMUCH_CONFIG}
+NOTMUCH_CONFIG="/nonexistent"
+test_C ${MAIL_DIR} <<EOF
+#include <notmuch-test.h>
+int main (int argc, char **argv) {
+  notmuch_status_t stat;
+  notmuch_database_t *db = NULL;
+
+  notmuch_status_t st = notmuch_database_load_config(argv[1], NULL, NULL, &db, NULL);
+  printf("db == NULL: %d\n", db == NULL);
+}
+EOF
+NOTMUCH_CONFIG=${old_NOTMUCH_CONFIG}
+cat <<EOF> EXPECTED
+== stdout ==
+db == NULL: 0
+== stderr ==
+EOF
+test_expect_equal_file EXPECTED OUTPUT
+
+
 test_done
-- 
2.33.0