fix: handle empty JULIAHUB_PROJECT_UUID var correctly

Author: pfitzseb

src/authentication.jl

@@ -506,10 +506,12 @@ _authentication(server::AbstractString; kwargs...) = _authentication(URIs.URI(se
 function _juliahub_project(
     project::Union{AbstractString, UUIDs.UUID, Nothing, Missing}
 )::Union{UUID, Nothing}
-    project = coalesce(
-        project,
-        get(ENV, "JULIAHUB_PROJECT_UUID", nothing),
-    )
+    project_env = get(ENV, "JULIAHUB_PROJECT_UUID", "")
+    if isempty(project_env)
+        project_env = nothing
+    end
+    project = coalesce(project, project_env)
+
     if isnothing(project)
         return nothing
     elseif isa(project, UUIDs.UUID)

test/authentication.jl

@@ -7,6 +7,13 @@
         @test JuliaHub._juliahub_project(nothing) === nothing
         @test JuliaHub._juliahub_project(missing) === nothing
     end
+    withenv("JULIAHUB_PROJECT_UUID" => "") do
+        @test JuliaHub._juliahub_project(uuid1) == UUIDs.UUID(uuid1)
+        @test_throws ArgumentError JuliaHub._juliahub_project("invalid")
+        @test_throws ArgumentError JuliaHub._juliahub_project("")
+        @test JuliaHub._juliahub_project(nothing) === nothing
+        @test JuliaHub._juliahub_project(missing) === nothing
+    end
     withenv("JULIAHUB_PROJECT_UUID" => uuid1) do
         @test JuliaHub._juliahub_project(uuid2) == UUIDs.UUID(uuid2)
         @test_throws ArgumentError JuliaHub._juliahub_project("invalid")