fixes

base/loading.jl

@@ -2254,6 +2254,7 @@ end
 
 # Unused
 const PKG_PRECOMPILE_HOOK = Ref{Function}()
+disable_parallel_precompile::Bool = false
 
 # Returns `nothing` or the new(ish) module
 function _require(pkg::PkgId, env=nothing)
@@ -2305,7 +2306,8 @@ function _require(pkg::PkgId, env=nothing)
         if JLOptions().use_compiled_modules == 1
             if !generating_output(#=incremental=#false)
                 project = active_project()
-                if !parallel_precompile_attempted && @isdefined(PrecompilePkgs) && project !== nothing && isfile(project) &&  project_file_manifest_path(project) !== nothing
+                if !generating_output() && !parallel_precompile_attempted && !disable_parallel_precompile && @isdefined(PrecompilePkgs) && project !== nothing &&
+                        isfile(project) && project_file_manifest_path(project) !== nothing
                     parallel_precompile_attempted = true
                     unlock(require_lock)
                     try

base/precompile.jl

@@ -342,10 +342,6 @@ function precompilepkgs(pkgs::Vector{String}=String[]; internal_call::Bool=false
 
     env = ExplicitEnv()
 
-    if isempty(pkgs)
-        pkgs = collect(keys(env.project_deps))
-    end
-
     # Windows sometimes hits a ReadOnlyMemoryError, so we halve the default number of tasks. Issue #2323
     # TODO: Investigate why this happens in windows and restore the full task limit
     default_num_tasks = Sys.iswindows() ? div(Sys.CPU_THREADS::Int, 2) + 1 : Sys.CPU_THREADS::Int + 1