systemd/coccinelle/systemd-definitions.iso

/* Statement isomorphisms - replace explicit checks against NULL with a
 * shorter variant, which relies on C's downgrade-to-bool feature.
 * The expression metavariables should be declared as pointers, however,
 * that doesn't work well with complex expressions like:
 * if (UNIT(p)->default_dependencies != NULL)
 */

Statement
@@
expression X;
statement S;
@@
if (X == NULL) S => if (!X) S

Statement
@@
expression X;
statement S;
@@
if (X != NULL) S => if (X) S
coccinelle: add explicit statement isomorphisms Coccinelle needs a custom isomorphism file with rules (isomorphisms) how to correctly rewrite conditions with explicit NULL checks (i.e. if (ptr == NULL)) to their shorter form (i.e. if (!ptr)). Coccinelle already contains such isomorphisms in its default .iso file, however, they're in the opposite direction, which results in useless output from coccinelle/equals-null.cocci. With this fix, `spatch` should no longer report patches like: @@ -628,8 +628,9 @@ static int path_deserialize_item(Unit *u f = path_result_from_string(value); if (f < 0) log_unit_debug(u, "Failed to parse result value: %s", value); - else if (f != PATH_SUCCESS) - p->result = f; + else {if (f != PATH_SUCCESS) + p->result = f; + } } else log_unit_debug(u, "Unknown serialization key: %s", key); 2019-04-26 22:42:16 +03:00			`/* Statement isomorphisms - replace explicit checks against NULL with a`
			`* shorter variant, which relies on C's downgrade-to-bool feature.`
			`* The expression metavariables should be declared as pointers, however,`
			`* that doesn't work well with complex expressions like:`
			`* if (UNIT(p)->default_dependencies != NULL)`
			`*/`

			`Statement`
			`@@`
			`expression X;`
			`statement S;`
			`@@`
			`if (X == NULL) S => if (!X) S`

			`Statement`
			`@@`
			`expression X;`
			`statement S;`
			`@@`
			`if (X != NULL) S => if (X) S`