don't precompile early in CI during build

src/API.jl

@@ -154,7 +154,9 @@ for f in (:develop, :add, :rm, :up, :pin, :free, :test, :build, :status, :why)
             pkgs = deepcopy(pkgs) # don't mutate input
             foreach(handle_package_input!, pkgs)
             ret = $f(ctx, pkgs; kwargs...)
-            $(f in (:add, :up, :pin, :free, :build)) && Pkg._auto_precompile(ctx)
+            $(f in (:add, :up, :pin, :free)) && Pkg._auto_precompile(ctx)
+            # don't precompile early in CI during build because the native cached code will be regenerated for the test setup
+            $(f == :build) && !(tryparse(Bool, get(ENV, "CI", "")) === true) && Pkg._auto_precompile(ctx)
             $(f in (:up, :pin, :free, :rm)) && Pkg._auto_gc(ctx)
             return ret
         end

test/api.jl

@@ -134,7 +134,9 @@ end
         @info "Auto precompilation enabled"
         Pkg.develop(Pkg.PackageSpec(path="packages/Dep4"))
         Pkg.develop(Pkg.PackageSpec(path="packages/NoVersion")) # a package with no version number
-        Pkg.build(io=iob) # should trigger auto-precomp
+        withenv("CI" => "false") do
+            Pkg.build(io=iob) # should trigger auto-precomp when not on CI
+        end
         @test occursin("Precompiling", String(take!(iob)))
         Pkg.precompile(io=iob)
         @test !occursin("Precompiling", String(take!(iob))) # test that the previous precompile was a no-op
@@ -153,7 +155,9 @@ end
 
         ENV["JULIA_PKG_PRECOMPILE_AUTO"]=1
         Pkg.develop(Pkg.PackageSpec(path="packages/BrokenDep"))
-        Pkg.build(io=iob) # should trigger auto-precomp and soft-error
+        withenv("CI" => "false") do
+            Pkg.build(io=iob) # should trigger auto-precomp and soft-error when not on CI
+        end
         @test occursin("Precompiling", String(take!(iob)))
         broken_packages = Pkg.API.pkgs_precompile_suspended
         @test length(broken_packages) == 1