Make TimeZones.jl relocatable

.github/workflows/CI.yml

@@ -93,12 +93,65 @@ jobs:
         with:
           version: "1.6"  # LTS / Oldest support version
       - uses: julia-actions/cache@v2
-      - shell: julia --color=yes --project=docs {0}
+      - shell: julia --color=yes --project=weakdeps {0}
         run: |
           using Pkg
           Pkg.add(PackageSpec(name="TimeZones", rev=ENV["SHA"]))
           using TimeZones
 
+  # TODO: Use shared project environments when the minimum version of Julia is 1.8 (e.g. `@sysimage`)
+  sysimage:
+    name: System Image - Julia ${{ matrix.version }} - TZJData ${{ matrix.tzjdata-version }} - ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        version:
+          - "1.6"  # LTS / Oldest supported version
+          - "1"    # Latest release
+        os:
+          - ubuntu-latest
+        tzjdata-version:
+          - "1.3.0"  # Version which does not support `artifact_dir`
+          - "1"
+    env:
+      JULIA_DEPOT_PATH: build-depot
+      TZJDATA_VERSION: ${{ matrix.tzjdata-version }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v2
+        with:
+          version: ${{ matrix.version }}
+      - uses: julia-actions/cache@v2
+      - name: Add TimeZones
+        shell: julia --color=yes --project=sysimage {0}
+        run: |
+          using Pkg
+          Pkg.add(PackageSpec(name="TZJData", version=ENV["TZJDATA_VERSION"]))
+          Pkg.add(PackageSpec(name="TimeZones", rev=ENV["SHA"]))
+      - name: Create sysimage
+        shell: julia --color=yes {0}
+        run: |
+          using Pkg
+          Pkg.add(PackageSpec(name="PackageCompiler", version="2"))
+          using PackageCompiler
+          create_sysimage(; project="sysimage", sysimage_path="sysimage.so")
+          # create_sysimage(; project=joinpath(first(DEPOT_PATH), "environments", "sysimage"), sysimage_path="sysimage.so")
+      - name: Validate sysimage works
+        shell: julia --color=yes --project=sysimage -Jsysimage.so {0}
+        run: |
+          using TimeZones
+          println(TimeZones._COMPILED_DIR[])
+      - name: Relocate Julia depot
+        run: mv build-depot sysimage-depot
+      - name: Validate sysimage works with relocated depot
+        shell: julia --color=yes --project=sysimage -Jsysimage.so {0}
+        run: |
+          using TimeZones
+          println(TimeZones._COMPILED_DIR[])
+        env:
+          JULIA_DEPOT_PATH: sysimage-depot
+
   benchmarks:
     name: Benchmarks
     runs-on: ubuntu-latest

Project.toml

@@ -4,6 +4,7 @@ authors = ["Curtis Vogt <[email protected]>"]
 version = "1.19.0"
 
 [deps]
+Artifacts = "56f22d72-fd6d-98f1-02f0-08ddc0907c33"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 Downloads = "f43a241f-c20a-4ad4-852c-f6b1247861c6"
 InlineStrings = "842dd82b-1e85-43dc-bf29-5d0ee9dffc48"
@@ -22,6 +23,7 @@ RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
 TimeZonesRecipesBaseExt = "RecipesBase"
 
 [compat]
+Artifacts = "1"
 Aqua = "0.8"
 Dates = "1"
 Downloads = "1"

src/TimeZones.jl

@@ -1,5 +1,6 @@
 module TimeZones
 
+using Artifacts: Artifacts
 using Dates
 using Printf
 using Scratch: @get_scratch!
@@ -33,13 +34,27 @@
 
 _scratch_dir() = @get_scratch!("build")
 
-const _COMPILED_DIR = Ref{String}(TZJData.ARTIFACT_DIR)
+const _COMPILED_DIR = Ref{String}()
 
 # TimeZone types used to disambiguate the context of a DateTime
 # abstract type UTC <: TimeZone end  # Already defined in the Dates stdlib
 abstract type Local <: TimeZone end
 
 function __init__()
+    # Set at runtime to ensure relocatability
+    _COMPILED_DIR[] = @static if isdefined(TZJData, :artifact_dir)
+        TZJData.artifact_dir()
+    else
+        # Backwards compatibility for TZJData versions below v1.3.1. The portion of the
+        # code which determines the `pkg_dir` could be replaced by `pkgdir(TZJData)` however
+        # the `pkgdir` function doesn't work well with relocated system images.
+        pkg = Base.identify_package(TZJData, "TZJData")
+        pkg_dir = dirname(dirname(Base.locate_package(pkg)))
+        artifact_dict = Artifacts.parse_toml(joinpath(pkg_dir, "Artifacts.toml"))
+        hash = Base.SHA1(artifact_dict["tzjdata"]["git-tree-sha1"])
+        Artifacts.artifact_path(hash)
+    end
+
     # Dates extension needs to happen everytime the module is loaded (issue #24)
     init_dates_extension()