plugins: imap-filter-sieve: Ignore secondary scripts that failed to c…

…ompile.

The IMAP FILTER=SIEVE capability does not execute more than a single script yet,
but once it does, it should not assert fail on secondary scripts that failed to
compile.

src/plugins/imap-filter-sieve/imap-filter-sieve.c

@@ -687,6 +687,15 @@ imap_sieve_filter_run_scripts(struct imap_filter_sieve_context *sctx,
 		struct sieve_script *script = scripts[i].script;
 		struct sieve_binary *sbin = scripts[i].binary;
 
+		if (sbin == NULL) {
+			if (debug) {
+				sieve_sys_debug(svinst,
+					"Skipping script from `%s'",
+					sieve_get_source(sbin));
+			}
+			continue;
+		}
+
 		cpflags = 0;
 		exflags = SIEVE_EXECUTE_FLAG_SKIP_RESPONSES;
 
@@ -701,9 +710,6 @@ imap_sieve_filter_run_scripts(struct imap_filter_sieve_context *sctx,
 			ehandler = ifsuser->master_ehandler;
 		}
 
-		/* Open */
-		i_assert(sbin != NULL);
-
 		/* Execute */
 		if (debug) {
 			sieve_sys_debug(svinst,