| author |  Alex Kladov <aleksey.kladov@gmail.com> 2024-04-15 13:57:41+01:00 |
| committer |  Andrew Kelley <andrew@ziglang.org> 2024-04-15 15:24:30-07:00 |
| log | ff18103ef6d383b6c6f81d996925f3a7856851e9 |
| tree | 9945d6abc1ed66b8c47e5b04e751f204bfd391cf |
| parent | 1e5075f81296cccd469a0829259231cb34337a02 |
std: improve std.once tests
* fix UB when Thread.spawn fails, and we try to join uninitialized
threads (through new `thread_count` variable).
* make sure that the tests pins down synchronization guarantees: in the
main thread, we can observe `1` due to synchronization from
`Thread.join()`. To make sure that once uses Acq/Rel, and not just
relaxed, we should also additionally check that each thread observes
1, regardless of whether it was the one to call once.1 files changed, 5 insertions(+), 1 deletions(-)
lib- std
lib/std/once.zig+5-1
| ... | ... | @@ -7,6 +7,7 @@ pub fn once(comptime f: fn () void) Once(f) { |
| 7 | 7 | } |
| 8 | 8 | |
| 9 | 9 | /// An object that executes the function `f` just once. |
| 10 | /// It is undefined behavior if `f` re-enters the same Once instance. | |
| 10 | 11 | pub fn Once(comptime f: fn () void) type { |
| 11 | 12 | return struct { |
| 12 | 13 | done: bool = false, |
| ... | ... | @@ -51,15 +52,18 @@ test "Once executes its function just once" { |
| 51 | 52 | global_once.call(); |
| 52 | 53 | } else { |
| 53 | 54 | var threads: [10]std.Thread = undefined; |
| 54 | defer for (threads) |handle| handle.join(); | |
| 55 | var thread_count: usize = 0; | |
| 56 | defer for (threads[0..thread_count]) |handle| handle.join(); | |
| 55 | 57 | |
| 56 | 58 | for (&threads) |*handle| { |
| 57 | 59 | handle.* = try std.Thread.spawn(.{}, struct { |
| 58 | 60 | fn thread_fn(x: u8) void { |
| 59 | 61 | _ = x; |
| 60 | 62 | global_once.call(); |
| 63 | if (global_number != 1) @panic("memory ordering bug"); | |
| 61 | 64 | } |
| 62 | 65 | }.thread_fn, .{0}); |
| 66 | thread_count += 1; | |
| 63 | 67 | } |
| 64 | 68 | } |
| 65 | 69 |