imapc: Fix assert-crash if server doesn't send EXISTS reply to SELECT

Fixes:
Panic: file imapc-sync.c: line 477 (imapc_sync_index): assertion failed: (mbox->sync_fetch_first_uid == 1)

diff --git a/src/lib-storage/index/imapc/imapc-storage.c b/src/lib-storage/index/imapc/imapc-storage.c
index 11a123bea8e80bf3677a25ef82306674adfadd0d..4b55ede613929946a7adb519ccc053f67ee132f5 100644 (file)
--- a/src/lib-storage/index/imapc/imapc-storage.c
+++ b/src/lib-storage/index/imapc/imapc-storage.c
@@ -540,21 +540,37 @@ static bool imapc_mailbox_want_examine(struct imapc_mailbox *mbox)
                 (mbox->box.flags & MAILBOX_FLAG_SAVEONLY) != 0);
 }
 
+static bool
+imapc_mailbox_verify_select(struct imapc_mailbox *mbox, const char **error_r)
+{
+       if (!mbox->exists_received)
+               *error_r = "EXISTS not received";
+       else
+               return TRUE;
+       return FALSE;
+}
+
 static void
 imapc_mailbox_reopen_callback(const struct imapc_command_reply *reply,
                              void *context)
 {
        struct imapc_mailbox *mbox = context;
+       const char *errmsg;
 
        i_assert(mbox->storage->reopen_count > 0);
        mbox->storage->reopen_count--;
        mbox->selecting = FALSE;
-       if (reply->state != IMAPC_COMMAND_STATE_OK) {
-               const char *errmsg = t_strdup_printf(
-                       "Reopening mailbox '%s' failed: %s",
-                       mbox->box.name, reply->text_full);
-               imapc_client_mailbox_reconnect(mbox->client_box, errmsg);
+       if (reply->state != IMAPC_COMMAND_STATE_OK)
+               errmsg = reply->text_full;
+       else if (imapc_mailbox_verify_select(mbox, &errmsg))
+               errmsg = NULL;
+
+       if (errmsg != NULL) {
+               imapc_client_mailbox_reconnect(mbox->client_box,
+                       t_strdup_printf("Reopening mailbox '%s' failed: %s",
+                                       mbox->box.name, errmsg));
        }
+
        imapc_client_stop(mbox->storage->client->client);
 }
 
@@ -578,6 +594,7 @@ static void imapc_mailbox_reopen(void *context)
 
        mbox->initial_sync_done = FALSE;
        mbox->selecting = TRUE;
+       mbox->exists_received = FALSE;
 
        cmd = imapc_client_mailbox_cmd(mbox->client_box,
                                       imapc_mailbox_reopen_callback, mbox);
@@ -600,12 +617,20 @@ imapc_mailbox_open_callback(const struct imapc_command_reply *reply,
                            void *context)
 {
        struct imapc_open_context *ctx = context;
+       const char *error;
 
        ctx->mbox->selecting = FALSE;
        ctx->mbox->selected = TRUE;
-       if (reply->state == IMAPC_COMMAND_STATE_OK)
-               ctx->ret = 0;
-       else if (reply->state == IMAPC_COMMAND_STATE_NO) {
+       if (reply->state == IMAPC_COMMAND_STATE_OK) {
+               if (!imapc_mailbox_verify_select(ctx->mbox, &error)) {
+                       mail_storage_set_critical(ctx->mbox->box.storage,
+                               "imapc: Opening mailbox '%s' failed: %s",
+                               ctx->mbox->box.name, error);
+                       ctx->ret = -1;
+               } else {
+                       ctx->ret = 0;
+               }
+       } else if (reply->state == IMAPC_COMMAND_STATE_NO) {
                imapc_copy_error_from_reply(ctx->mbox->storage,
                                            MAIL_ERROR_NOTFOUND, reply);
                ctx->ret = -1;
@@ -670,6 +695,7 @@ int imapc_mailbox_select(struct imapc_mailbox *mbox)
        imapc_mailbox_get_extensions(mbox);
 
        mbox->selecting = TRUE;
+       mbox->exists_received = FALSE;
        ctx.mbox = mbox;
        ctx.ret = -2;
        cmd = imapc_client_mailbox_cmd(mbox->client_box,