Repair restored sublibrary downgrade metadata

.github/workflows/sublibrary-downgrade.yml

@@ -167,6 +167,13 @@ jobs:
           [ -n "${{ inputs.skip }}" ] && effective="$effective,${{ inputs.skip }}"
           echo "Effective downgrade skip: $effective"
           echo "EFFECTIVE_SKIP=$effective" >> "$GITHUB_ENV"
+      - name: "Save project metadata for QA"
+        if: "${{ inputs.group-env-value == 'QA' }}"
+        shell: bash
+        run: |
+          save_dir="$RUNNER_TEMP/sciml-downgrade-original-project"
+          mkdir -p "$save_dir"
+          cp "${{ matrix.project }}/Project.toml" "$save_dir/Project.toml"
       - uses: julia-actions/julia-downgrade-compat@v2
         with:
           projects: ${{ matrix.project }}
@@ -180,6 +187,19 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
         with:
           project: ${{ matrix.project }}
+      - name: "Checkout SciML/.github for the downgrade metadata helper"
+        if: "${{ inputs.group-env-value == 'QA' }}"
+        uses: actions/checkout@v7
+        with:
+          repository: SciML/.github
+          path: .sciml-dotgithub
+      - name: "Restore project metadata before QA"
+        if: "${{ inputs.group-env-value == 'QA' }}"
+        shell: bash
+        run: |
+          save_dir="$RUNNER_TEMP/sciml-downgrade-original-project"
+          cp "$save_dir/Project.toml" "${{ matrix.project }}/Project.toml"
+          julia --startup-file=no .sciml-dotgithub/scripts/restore_downgraded_project.jl "${{ matrix.project }}"
       - uses: julia-actions/julia-runtest@v1
         with:
           project: ${{ matrix.project }}

scripts/restore_downgraded_project.jl

@@ -0,0 +1,69 @@
+#!/usr/bin/env julia
+
+using TOML
+
+function restored_manifest_entry(project::AbstractDict, path::AbstractString)
+    entry = Dict{String, Any}(
+        "path" => path,
+        "uuid" => project["uuid"],
+    )
+    hard_deps = sort!(collect(keys(get(project, "deps", Dict{String, Any}()))))
+    isempty(hard_deps) || (entry["deps"] = hard_deps)
+    for key in ("weakdeps", "extensions")
+        values = get(project, key, nothing)
+        values isa AbstractDict && !isempty(values) && (entry[key] = deepcopy(values))
+    end
+    haskey(project, "version") && (entry["version"] = project["version"])
+    return entry
+end
+
+function local_manifest_entry(entries, manifest_dir::AbstractString, project_dir::AbstractString)
+    matches = findall(entries) do entry
+        path = get(entry, "path", nothing)
+        path isa AbstractString || return false
+        return realpath(abspath(manifest_dir, path)) == realpath(project_dir)
+    end
+    length(matches) == 1 || error(
+        "expected exactly one local manifest entry for $project_dir, found $(length(matches))",
+    )
+    return only(matches)
+end
+
+"""
+    restore_downgraded_project(project_dir)
+
+Repair the local package entry in a downgrade-generated `Manifest.toml` after
+restoring the package's original `Project.toml`. Resolved package versions and
+test-only manifest entries are retained.
+"""
+function restore_downgraded_project(project_dir::AbstractString)
+    project_dir = normpath(abspath(project_dir))
+    project_path = joinpath(project_dir, "Project.toml")
+    manifest_path = joinpath(project_dir, "Manifest.toml")
+    project = TOML.parsefile(project_path)
+    manifest = TOML.parsefile(manifest_path)
+
+    package_name = project["name"]
+    entries = manifest["deps"][package_name]
+    entry_index = local_manifest_entry(entries, dirname(manifest_path), project_dir)
+    existing_path = entries[entry_index]["path"]
+    entries[entry_index] = restored_manifest_entry(project, existing_path)
+    pop!(manifest, "project_hash", nothing)
+
+    temporary_path, io = mktemp(dirname(manifest_path))
+    try
+        TOML.print(io, manifest; sorted = true)
+        close(io)
+        mv(temporary_path, manifest_path; force = true)
+    catch
+        close(io)
+        rm(temporary_path; force = true)
+        rethrow()
+    end
+    return nothing
+end
+
+if abspath(PROGRAM_FILE) == @__FILE__
+    length(ARGS) == 1 || error("usage: restore_downgraded_project.jl PROJECT_DIR")
+    restore_downgraded_project(only(ARGS))
+end

test/runtests.jl

@@ -8,6 +8,70 @@ include(SCRIPT)
 const DEVELOP_SCRIPT = joinpath(@__DIR__, "..", "scripts", "develop_sources.jl")
 include(DEVELOP_SCRIPT)
 
+const RESTORE_DOWNGRADE_SCRIPT =
+    joinpath(@__DIR__, "..", "scripts", "restore_downgraded_project.jl")
+include(RESTORE_DOWNGRADE_SCRIPT)
+
+@testset "restore downgraded project manifest metadata" begin
+    root = mktempdir()
+    write(
+        joinpath(root, "Project.toml"), """
+        name = "Root"
+        uuid = "00000000-0000-0000-0000-000000000001"
+        version = "1.2.3"
+
+        [deps]
+        Runtime = "00000000-0000-0000-0000-000000000002"
+
+        [weakdeps]
+        Weak = "00000000-0000-0000-0000-000000000003"
+
+        [extensions]
+        RootWeakExt = "Weak"
+        """,
+    )
+    write(
+        joinpath(root, "Manifest.toml"), """
+        julia_version = "1.10.0"
+        manifest_format = "2.0"
+        project_hash = "stale"
+
+        [[deps.Root]]
+        deps = ["Runtime", "TestOnly"]
+        path = "."
+        uuid = "00000000-0000-0000-0000-000000000001"
+        version = "1.2.3"
+
+        [[deps.Runtime]]
+        git-tree-sha1 = "runtime-tree"
+        uuid = "00000000-0000-0000-0000-000000000002"
+        version = "2.0.0"
+
+        [[deps.TestOnly]]
+        git-tree-sha1 = "test-tree"
+        uuid = "00000000-0000-0000-0000-000000000004"
+        version = "3.0.0"
+        """,
+    )
+
+    before = TOML.parsefile(joinpath(root, "Manifest.toml"))
+    restore_downgraded_project(root)
+    after = TOML.parsefile(joinpath(root, "Manifest.toml"))
+
+    @test !haskey(after, "project_hash")
+    @test after["deps"]["Runtime"] == before["deps"]["Runtime"]
+    @test after["deps"]["TestOnly"] == before["deps"]["TestOnly"]
+    root_entry = only(after["deps"]["Root"])
+    @test root_entry["path"] == "."
+    @test root_entry["uuid"] == "00000000-0000-0000-0000-000000000001"
+    @test root_entry["version"] == "1.2.3"
+    @test root_entry["deps"] == ["Runtime"]
+    @test root_entry["weakdeps"] == Dict(
+        "Weak" => "00000000-0000-0000-0000-000000000003",
+    )
+    @test root_entry["extensions"] == Dict("RootWeakExt" => "Weak")
+end
+
 # Build a fixture monorepo `lib/` tree in a temp dir.
 #   A  (base, no internal deps)
 #   B  deps A