enforce buff channel size > 0 (#2952)

* fix(stdlib): enforce BufferedChannel size > 0 and add regression test

* chore(repo): ignore cmake/test artifacts

* Formatting

---------

Co-authored-by: Christoffer Lerno <christoffer.lerno@gmail.com>

.gitignore

@@ -73,6 +73,9 @@ out/
 /cmake-build-debug/
 /cmake-build-release/
 
+CMakeFiles/cmake.check_cache
+CMakeCache.txt
+
 # etags(Emacs), ctags, gtags
 TAGS
 GPATH
@@ -94,8 +97,8 @@ result
 
 # tests
 /test/tmp/*
-/test/testrun
-/test/test_suite_runner
+testrun
+test_suite_runner
 
 # patches, originals and rejects
 *.patch

lib/std/threads/buffered_channel.c3

@@ -21,6 +21,9 @@ struct BufferedChannelImpl @private
 	Type[*] buf;
 }
 
+<*
+ @require size > 0: "channel size must be > 0"
+*>
 fn void? BufferedChannel.init(&self, Allocator allocator, usz size = 1)
 {
 	BufferedChannelImpl* channel = allocator::new_with_padding(allocator, BufferedChannelImpl, Type.sizeof * size)!;
@@ -155,4 +158,3 @@ fn void? BufferedChannel.close(self) @maydiscard // Remove optional in 0.8.0
 	channel.mu.unlock();
 
 }
-

test/test_suite/stdlib/channels.c3

@@ -0,0 +1,8 @@
+import std::thread;
+
+fn int main()
+{
+	BufferedChannel{int} c;
+	c.init(mem, 0)!!; // #error: @require "size > 0" violated: 'channel size must be > 0'.
+	return 0;
+}