We usually zero-initialize vectors like string_vector names = empty_vector; Allocating and zeroing separately is frequently useful however. Document the pattern string_vector names; names = (string_vector)empty_vector; where "(string_vector)empty_vector" is a compound literal. Link: http://mid.mail-archive.com/20230221183810.vjilfbmj3woqivlj@redhat.com Suggested-by: Eric Blake <eblake(a)redhat.com&gt; Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- Notes: I'll pick this patch to libnbd as well, once merged in nbdkit. context:-U10 common/utils/vector.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/common/utils/vector.h b/common/utils/vector.h index ac28c0b5363a..7337d26893eb 100644 --- a/common/utils/vector.h +++ b/common/utils/vector.h @@ -55,28 +55,34 @@ /* Use of this macro defines a new type called ‘name’ containing an * extensible vector of ‘type’ elements. For example: * * DEFINE_VECTOR_TYPE (string_vector, char *); * * defines a new type called ‘string_vector’ as a vector of ‘char *’. * You can create variables of this type: * * string_vector names = empty_vector; * + * or + * + * string_vector names; + * names = (string_vector)empty_vector; + * * where ‘names.ptr[]’ will be an array of strings and ‘names.len’ * will be the number of strings. There are no get/set accessors. To * iterate over the strings you can use the ‘.ptr’ field directly: * * for (size_t i = 0; i < names.len; ++i) * printf ("%s\n", names.ptr[i]); * - * Initializing with ‘empty_vector’ sets ‘.ptr = NULL’ and ‘.len = 0’. + * Initializing with ‘empty_vector’, or assigning the compound literal + * ‘(string_vector)empty_vector’, sets ‘.ptr = NULL’ and ‘.len = 0’. * * DEFINE_VECTOR_TYPE also defines utility functions. For the full * list see the definition below, but useful functions include: * * ‘name’_append (eg. ‘string_vector_append’) * - Append a new element at the end. This operation is cheap. * * ‘name’_insert (eg. ‘string_vector_insert’) * - Insert a new element at the beginning, middle or end. This * operation is more expensive because existing elements may need

The beautiful world of uncontained dependencies: - We restrict mockall to 0.11.0, which in practice currently expands to 0.11.4, - mockall depends on predicates-tree, - predicates-tree depends on predicates-core, - approx. two weeks ago, predicates-tree and predicates-core have seen *PATCHLEVEL* upgrades (1.0.7 -> 1.0.9, and 1.0.5 -> 1.0.6, respectively) that now require "rustc 1.64.0 or newer". RHEL-9.2 will eventually ship rustc 1.66, but RHEL-9.2 has not been released. The above rustc requirement bump breaks the nbdkit build on RHEL-9.1 -- which provides rustc 1.62. Restrict predicates-{tree,core} to {1.0.7,1.0.5}. (Side commentary: when such things can happen via a *patchlevel* upgrade, that makes a total mockery of "semantic versioning" <https://en.wikipedia.org/wiki/Software_versioning#Semantic_versioning>.) Signed-off-by: Laszlo Ersek <lersek(a)redhat.com&gt; --- plugins/rust/Cargo.toml | 2 ++ 1 file changed, 2 insertions(+) diff --git a/plugins/rust/Cargo.toml b/plugins/rust/Cargo.toml index 45d8a755e6e3..64ed193a0008 100644 --- a/plugins/rust/Cargo.toml +++ b/plugins/rust/Cargo.toml @@ -29,6 +29,8 @@ errno = "0.2.5" lazy_static = "1.2.0" memoffset = "0.6.3" mockall = "0.11.0" +predicates-core = "=1.0.5" +predicates-tree = "=1.0.7" [[example]] name = "ramdisk"