avoid loading pkg until needed

.github/workflows/ci.yml

@@ -14,32 +14,25 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        julia-version:
-          - "nightly"
-        os:
-          - ubuntu-latest
-        julia-arch:
-          - x64
+        include:
+          - os: ubuntu-latest
+            julia-arch: x64
+            julia-version: 'nightly'
+          - os: windows-latest
+            julia-arch: x64
+            julia-version: 'nightly'
+          - os: macos-latest
+            julia-arch: aarch64
+            julia-version: 'nightly'
     steps:
-      - uses: actions/checkout@v2
-      - uses: julia-actions/setup-julia@v1
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.julia-version }}
           arch: ${{ matrix.julia-arch }}
-      - name: Cache artifacts
-        uses: actions/cache@v2
-        env:
-          cache-name: cache-artifacts
+      - uses: julia-actions/julia-buildpkg@v1
+      - uses: julia-actions/julia-runtest@v1
+      - uses: julia-actions/julia-processcoverage@v1
+      - uses: codecov/codecov-action@v2
         with:
-          path: ~/.julia/artifacts
-          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
-          restore-keys: |
-            ${{ runner.os }}-test-${{ env.cache-name }}-
-            ${{ runner.os }}-test-
-            ${{ runner.os }}-
-      - uses: julia-actions/julia-buildpkg@latest
-      - uses: julia-actions/julia-runtest@latest
-      - uses: julia-actions/julia-uploadcodecov@v0.1
-        continue-on-error: true
-      - uses: julia-actions/julia-uploadcoveralls@v0.1
-        continue-on-error: true
+          files: lcov.info

.gitignore

@@ -0,0 +1,2 @@
+
+Manifest.toml

src/LazyArtifacts.jl

@@ -9,7 +9,72 @@ using Artifacts: Artifacts,
 export artifact_exists, artifact_path, artifact_meta, artifact_hash,
        select_downloadable_artifacts, find_artifacts_toml, @artifact_str
 
-# define a function for satisfying lazy Artifact downloads
-using Pkg.Artifacts: ensure_artifact_installed
+using Base.BinaryPlatforms: AbstractPlatform, HostPlatform
+using Base: SHA1
+
+# We are mimicking Pkg.Artifacts.ensure_artifact_installed here so that we can
+# check if the artifact is already installed before loading Pkg.
+# Then if we need to load Pkg we do it in a subprocess to avoid precompilation
+# complexity.
+
+"""
+       ensure_artifact_installed(name::String, artifacts_toml::String;
+                                   platform::AbstractPlatform = HostPlatform(),
+                                   pkg_uuid::Union{Base.UUID,Nothing}=nothing,
+                                   verbose::Bool = false,
+                                   quiet_download::Bool = false,
+                                   io::IO=stderr)
+
+Ensures an artifact is installed, downloading it via the download information stored in
+`artifacts_toml` if necessary.  Throws an error if unable to install.
+"""
+function ensure_artifact_installed(name::String, artifacts_toml::String;
+    platform::AbstractPlatform=HostPlatform(),
+    pkg_uuid::Union{Base.UUID,Nothing}=nothing,
+    verbose::Bool=false,
+    quiet_download::Bool=false,
+    io::IO=stderr)
+    meta = artifact_meta(name, artifacts_toml; pkg_uuid=pkg_uuid, platform=platform)
+    if meta === nothing
+        error("Cannot locate artifact '$(name)' in '$(artifacts_toml)'")
+    end
+
+    return ensure_artifact_installed(name, meta, artifacts_toml;
+        platform, verbose, quiet_download, io)
+end
+
+function ensure_artifact_installed(name::String, meta::Dict, artifacts_toml::String;
+    platform::AbstractPlatform=HostPlatform(),
+    verbose::Bool=false,
+    quiet_download::Bool=false,
+    io::IO=stderr)
+
+    hash = SHA1(meta["git-tree-sha1"])
+    if !artifact_exists(hash)
+        # loading Pkg is a bit slow, so we only do it if we need to
+        # and do it in a subprocess to avoid precompilation complexity
+        code = """
+            Pkg = Base.require_stdlib(Base.PkgId(Base.UUID("44cfe95a-1eb2-52ea-b672-e2afdf69b78f"), "Pkg"));
+            Pkg.Artifacts.try_artifact_download_sources(
+                $(repr(name)),
+                Base.$(repr(hash)),
+                $(repr(meta)),
+                $(repr(artifacts_toml));
+                platform = Base.BinaryPlatforms.$(repr(platform)),
+                verbose = $(repr(verbose)),
+                quiet_download = $(repr(quiet_download)),
+                io = stderr
+            )
+        """
+        out = readchomp(pipeline(`$(Base.julia_cmd()) -E $code`, stderr=io))
+        return Meta.parse(out)
+    else
+        return artifact_path(hash)
+    end
+end
+
+if Base.generating_output()
+    precompile(Tuple{typeof(Artifacts._artifact_str), Module, String, Base.SubString{String}, String, Base.Dict{String, Any}, Base.SHA1, Base.BinaryPlatforms.Platform, Base.Val{LazyArtifacts}})
+end
 
 end