Change collect_delay to be a Dates.Period

This gives greater clarity on the meaning behind `collect_delay`.

src/API.jl

@@ -263,22 +263,19 @@ function __installed(mode::PackageMode=PKGMODE_MANIFEST)
 end
 
 """
-    gc(ctx::Context=Context(); kwargs...)
+    gc(ctx::Context=Context(); collect_delay::Period=Day(30), kwargs...)
 
 Garbage-collect package and artifact installations by sweeping over all known
 `Manifest.toml` and `Artifacts.toml` files, noting those that have been deleted, and then
 finding artifacts and packages that are thereafter not used by any other projects.  This
 method will only remove package versions and artifacts that have been continually un-used
 for a period of `collect_delay`; which defaults to thirty days.
 """
-function gc(ctx::Context=Context(); collect_delay=60*60*24*30, kwargs...)
+function gc(ctx::Context=Context(); collect_delay::Period=Day(30), kwargs...)
     Context!(ctx; kwargs...)
     ctx.preview && preview_info()
     env = ctx.env
 
-    # Convert to a DateTime immediately, offering millisecond resolution
-    collect_delay = Millisecond(round(Int64,1000*collect_delay))
-
     # First, we load in our `manifest_usage.toml` files which will tell us when our
     # "index files" (`Manifest.toml`, `Artifacts.toml`) were last used.  We will combine
     # this knowledge across depots, condensing it all down to a single entry per extant
@@ -494,7 +491,7 @@ function gc(ctx::Context=Context(); collect_delay=60*60*24*30, kwargs...)
     for depot in depots()
         # We track orphaned objects on a per-depot basis, writing out our `orphaned.toml`
         # tracking file immediately, only pushing onto the overall `*_to_delete` lists if
-        # the package has been orphaned for at least `collect_delay` seconds.
+        # the package has been orphaned for at least a period of `collect_delay`
         depot_orphaned_packages = String[]
         depot_orphaned_artifacts = String[]
 

test/artifacts.jl

@@ -2,7 +2,7 @@ module ArtifactTests
 
 using Test, Pkg.Artifacts, Pkg.BinaryPlatforms, Pkg.PlatformEngines
 import Pkg.Artifacts: pack_platform!, unpack_platform, with_artifacts_directory
-using Pkg.TOML
+using Pkg.TOML, Dates
 import Base: SHA1
 
 include("utils.jl")
@@ -359,7 +359,7 @@ end
         # This should reap the `die_hash` immediately, as it has already been moved to
         # the orphaned list.
         sleep(0.2)
-        Pkg.gc(;collect_delay=0.1)
+        Pkg.gc(;collect_delay=Millisecond(100))
         @test artifact_exists(live_hash)
         @test !artifact_exists(die_hash)
 
@@ -374,7 +374,7 @@ end
         # Next, unbind the live_hash, then run with collect_delay=0, and ensure that
         # things are cleaned up immediately.
         unbind_artifact!(artifacts_toml, "live")
-        Pkg.gc(;collect_delay=0)
+        Pkg.gc(;collect_delay=Second(0))
         @test !artifact_exists(live_hash)
         @test !artifact_exists(die_hash)
     end

test/pkg.jl

@@ -6,6 +6,7 @@ import Random: randstring
 import LibGit2
 using Test
 using UUIDs
+using Dates
 
 using Pkg
 using Pkg.Types
@@ -135,11 +136,11 @@ temp_pkg_dir() do project_path
         pkgdir = joinpath(Pkg.depots1(), "packages")
 
         # Test to ensure that with a long enough collect_delay, nothing gets reaped
-        Pkg.gc(;collect_delay=1000)
+        Pkg.gc(;collect_delay=Day(1000))
         @test !isempty(readdir(pkgdir))
 
         # Setting collect_delay to zero causes it to be reaped immediately, howeveage
-        Pkg.gc(;collect_delay=0)
+        Pkg.gc(;collect_delay=Second(0))
         @test isempty(readdir(pkgdir))
     end