From 7d9dcd3adcbd994dd7948af923cf75d4d136719c Mon Sep 17 00:00:00 2001
From: Valentin Churavy <v.churavy@gmail.com>
Date: Sun, 19 Dec 2021 14:51:31 -0500
Subject: [PATCH] All infrastructure to allow Pkg to download all Artifacts

---
 base/binaryplatforms.jl           | 11 ++++++--
 stdlib/Artifacts/src/Artifacts.jl | 46 +++++++++++++++++++++++++++----
 2 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/base/binaryplatforms.jl b/base/binaryplatforms.jl
index cfd7412faf656..7201d0a0702e7 100644
--- a/base/binaryplatforms.jl
+++ b/base/binaryplatforms.jl
@@ -1039,6 +1039,10 @@ platforms_match(a::AbstractPlatform, b::AbstractString) = platforms_match(a, str
 platforms_match(a::AbstractString, b::AbstractString) = platforms_match(string(a)::String, string(b)::String)
 
 
+function filter_by_platform(download_info::Dict, platform::AbstractPlatform)
+    return collect(filter(p -> platforms_match(p, platform), keys(download_info)))
+end
+
 """
     select_platform(download_info::Dict, platform::AbstractPlatform = HostPlatform())
 
@@ -1051,8 +1055,7 @@ match exactly, however attributes such as compiler ABI can have wildcards
 within them such as `nothing` which matches any version of GCC.
 """
 function select_platform(download_info::Dict, platform::AbstractPlatform = HostPlatform())
-    ps = collect(filter(p -> platforms_match(p, platform), keys(download_info)))
-
+    ps = filter_by_platform(download_info, platform)
     if isempty(ps)
         return nothing
     end
@@ -1063,6 +1066,10 @@ function select_platform(download_info::Dict, platform::AbstractPlatform = HostP
     # down, we just sort by triplet, then pick the last one.  This has the effect
     # of generally choosing the latest release (e.g. a `libgfortran5` tarball
     # rather than a `libgfortran3` tarball)
+    # XXX: The reasoning above seems wrong. We actually need to download all of them
+    #      since some of them could be custom platform tags. Future users should use
+    #      the `filter_by_platform` function instead.
+
     p = last(sort(ps, by = p -> triplet(p)))
     return download_info[p]
 end
diff --git a/stdlib/Artifacts/src/Artifacts.jl b/stdlib/Artifacts/src/Artifacts.jl
index 645e77944208b..c9feba3ab54ae 100644
--- a/stdlib/Artifacts/src/Artifacts.jl
+++ b/stdlib/Artifacts/src/Artifacts.jl
@@ -375,6 +375,15 @@ function artifact_meta(name::String, artifacts_toml::String;
     return artifact_meta(name, artifact_dict, artifacts_toml; platform=platform)
 end
 
+function to_dl_dict(meta, name, artifacts_toml)
+    dl_dict = Dict{AbstractPlatform,Dict{String,Any}}()
+    for x in meta
+        x::Dict{String}
+        dl_dict[unpack_platform(x, name, artifacts_toml)] = x
+    end
+    return dl_dict
+end
+
 function artifact_meta(name::String, artifact_dict::Dict, artifacts_toml::String;
                        platform::AbstractPlatform = HostPlatform())
     if !haskey(artifact_dict, name)
@@ -384,11 +393,7 @@ function artifact_meta(name::String, artifact_dict::Dict, artifacts_toml::String
 
     # If it's an array, find the entry that best matches our current platform
     if isa(meta, Vector)
-        dl_dict = Dict{AbstractPlatform,Dict{String,Any}}()
-        for x in meta
-            x::Dict{String}
-            dl_dict[unpack_platform(x, name, artifacts_toml)] = x
-        end
+        dl_dict = to_dl_dict(meta, name, artifacts_toml)
         meta = select_platform(dl_dict, platform)
     # If it's NOT a dict, complain
     elseif !isa(meta, Dict)
@@ -406,6 +411,37 @@ function artifact_meta(name::String, artifact_dict::Dict, artifacts_toml::String
     return meta
 end
 
+function all_artifact_meta(name::String, artifact_dict::Dict, artifacts_toml::String;
+                           platform::AbstractPlatform = HostPlatform())
+    if !haskey(artifact_dict, name)
+        return nothing
+    end
+    meta = artifact_dict[name]
+
+    # If it's an array, find the entry that best matches our current platform
+    if isa(meta, Vector)
+        dl_dict = to_dl_dict(meta, name, artifacts_toml)
+        metas = filter_by_platform(dl_dict, platform)
+    # If it's NOT a dict, complain
+    elseif !isa(meta, Dict)
+        @error("Invalid artifacts file at $(artifacts_toml): artifact '$name' malformed, must be array or dict!")
+        return nothing
+    else
+        metas = [meta]
+    end
+
+    # This is such a no-no, we are going to call it out right here, right now.
+    for meta in metas
+        if meta !== nothing && !haskey(meta, "git-tree-sha1")
+            @error("Invalid artifacts file at $(artifacts_toml): artifact '$name' contains no `git-tree-sha1`!")
+            return nothing
+        end
+    end
+
+    # Return the full meta-dict.
+    return metas
+end
+
 """
     artifact_hash(name::String, artifacts_toml::String;
                   platform::AbstractPlatform = HostPlatform())