From a1dd8017d655d18582c0069f01ccf077e54f34f2 Mon Sep 17 00:00:00 2001
From: Valentin Churavy <vchuravy@users.noreply.github.com>
Date: Tue, 7 Dec 2021 17:06:45 -0500
Subject: [PATCH] Look for package name in `[extras]` for Preferences (#43361)

* Look for package name in `[extras]`

When Preferences.jl set's a preferences in a non-top-level package,
it adds that package to the `[extras]` entries in the project path.

Package loading should have used thhose entries to map the module uuid
to the key name in the Preferences.toml

Fixes https://github.com/JuliaPackaging/Preferences.jl/issues/24

Co-authored-by: Elliot Saba <staticfloat@gmail.com>
(cherry picked from commit 8197c418e1d806f5faf1fd900c78068ea8046e1d)
---
 base/loading.jl | 13 ++++++++++++-
 test/loading.jl | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/base/loading.jl b/base/loading.jl
index 2b1f934ff6ffeb..d406d3a409737e 100644
--- a/base/loading.jl
+++ b/base/loading.jl
@@ -1652,7 +1652,8 @@ function srctext_files(f::IO, srctextpos::Int64)
 end
 
 # Test to see if this UUID is mentioned in this `Project.toml`; either as
-# the top-level UUID (e.g. that of the project itself) or as a dependency.
+# the top-level UUID (e.g. that of the project itself), as a dependency,
+# or as a extra for Preferences.
 function get_uuid_name(project::Dict{String, Any}, uuid::UUID)
     uuid_p = get(project, "uuid", nothing)::Union{Nothing, String}
     name = get(project, "name", nothing)::Union{Nothing, String}
@@ -1667,6 +1668,16 @@ function get_uuid_name(project::Dict{String, Any}, uuid::UUID)
             end
         end
     end
+    for subkey in ("deps", "extras")
+        subsection = get(project, subkey, nothing)::Union{Nothing, Dict{String, Any}}
+        if subsection !== nothing
+            for (k, v) in subsection
+                if uuid == UUID(v::String)
+                    return k
+                end
+            end
+        end
+    end
     return nothing
 end
 
diff --git a/test/loading.jl b/test/loading.jl
index c56f6c463a21f5..3970813fbd29b8 100644
--- a/test/loading.jl
+++ b/test/loading.jl
@@ -189,6 +189,42 @@ end
     end
 end
 
+# extras
+@testset "extras" begin
+    mktempdir() do dir
+        project_file = joinpath(dir, "Project.toml")
+        touch(project_file) # dummy_uuid calls realpath
+        # various UUIDs to work with
+        proj_uuid = dummy_uuid(project_file)
+        root_uuid = uuid4()
+        this_uuid = uuid4()
+
+        old_load_path = copy(LOAD_PATH)
+        try
+            copy!(LOAD_PATH, [project_file])
+            write(project_file, """
+            name = "Root"
+            uuid = "$root_uuid"
+            [extras]
+            This = "$this_uuid"
+            """)
+            # look up various packages by name
+            root = Base.identify_package("Root")
+            this = Base.identify_package("This")
+            that = Base.identify_package("That")
+
+            @test root.uuid == root_uuid
+            @test this == nothing
+            @test that == nothing
+
+            @test Base.get_uuid_name(project_file, this_uuid) == "This"
+        finally
+            copy!(LOAD_PATH, old_load_path)
+        end
+    end
+end
+
+
 ## functional testing of package identification, location & loading ##
 
 saved_load_path = copy(LOAD_PATH)