Use atomic writes when binding artifacts

[staticfloat]

EDIT: No longer doing this, Jameson has Shown Me The Way™

We need to clear this cache when modifying the TOML file. This should fix #3212.

It might be nice to expose a Base.drop_parsed_toml(path::String) API so that I don't have to manually reach into TOML_CACHE.d here like this.

[vtjnash]

Ah, these lines are buggy, causing this failure. Pkg must never open an existing file for writing, as it causes problems for the filesystem.

[vtjnash]

e.g. JuliaLang/julia#36664

[vtjnash]

and JuliaLang/julia#39892

[KristofferC]

I think JuliaLang/julia#46944 removed the check that was intended to catch things like this.

[vtjnash]

It did, but that check was fundamentally flawed, and didn't actually check for things like this, it merely checked for attempts to test for this problem.

[vtjnash]

Excellent

[IanButterworth]

Might as well shoot for all green given the stdlib check is fixed on master now

[IanButterworth]

Made an issue for the MacOS error which appears unrelated but has been sticking around #3238

Also the historical stdlib check is now removed as of #3096

[simeonschaub]

@staticfloat This broke support for relative Artifact.toml paths in JuliaPackaging/ArtifactUtils.jl#19. Should this be fixed here with something like:

diff --git a/src/Artifacts.jl b/src/Artifacts.jl
index 538755e23..dca06e469 100644
--- a/src/Artifacts.jl
+++ b/src/Artifacts.jl
@@ -223,7 +223,8 @@ function bind_artifact!(artifacts_toml::String, name::String, hash::SHA1;
 
     # Spit it out onto disk
     let artifact_dict = artifact_dict
-        temp_artifacts_toml = tempname(dirname(artifacts_toml))
+        parent_dir = dirname(artifacts_toml)
+        temp_artifacts_toml = isempty(parent_dir) ? : tempname(pwd()) : tempname(parent_dir)
         open(temp_artifacts_toml, "w") do io
             TOML.print(io, artifact_dict, sorted=true)
         end

or was this never a supported use case and ArtifactUtils should be updated?

[staticfloat]

A patch like yours should be fine.