Make code work across Julia 1.6 and 1.7+

Author: vchuravy

src/AutoBuild.jl

@@ -1425,6 +1425,29 @@ const uuid_package = UUID("cfb74b52-ec16-5bb7-a574-95d9e393895e")
 # For even more interesting historical reasons, we append an extra
 # "_jll" to the name of the new package before computing its UUID.
 jll_uuid(name) = bb_specific_uuid5(uuid_package, "$(name)_jll")
+
+function find_uuid(ctx, pkg)
+    if Pkg.Types.has_uuid(pkgspec)
+        return pkg.uuid
+    else
+    @static if VERSION >= 1.7
+        uuids = Pkg.Types.registered_uuids(ctx.registries, depname)
+    else
+        uuids = Pkg.Types.registered_uuids(ctx, depname)
+    end
+    if isempty(uuids)
+        return nothing
+    end
+    if length(uuids) == 1
+        return first(uuids)
+    end
+    depname = getname(pkg)
+    error("""
+    Multiple UUIDs found for package `$(depname)`.
+    Use `PackageSpec(name = \"$(depname)\", uuid = ..." to specify the UUID explicitly.
+    """)
+end
+
 function build_project_dict(name, version, dependencies::Array{Dependency}, julia_compat::String=DEFAULT_JULIA_VERSION_SPEC; lazy_artifacts::Bool=false, kwargs...)
     Pkg.Types.semver_spec(julia_compat) # verify julia_compat is valid
     project = Dict(
@@ -1442,20 +1465,9 @@ function build_project_dict(name, version, dependencies::Array{Dependency}, juli
     for dep in dependencies
         pkgspec = getpkg(dep)
         depname = getname(dep)
-        if Pkg.Types.has_uuid(pkgspec)
-            uuid = pkgspec.uuid
-        else
-            uuids = Pkg.Types.registered_uuids(ctx.registries, depname)
-            if isempty(uuids)
-                uuid = jll_uuid(depname)
-            elseif length(uuids) == 1
-                uuid = first(uuids)
-            else
-                error("""
-                Multiple UUIDs found for package `$(depname)`.
-                Use `PackageSpec(name = \"$(depname)\", uuid = ..." to specify the UUID explicitly.
-                """)
-            end
+        uuid = findname(ctx, pkgspec)
+        if uuid === nothing
+            uuid = jll_uuid(depname)
         end
         project["deps"][depname] = string(uuid)
         if dep isa Dependency && length(dep.compat) > 0