MODULES: lib1, main

STEP 0:
    libs: lib1, main
    dirty js modules: lib1, main
    dirty js files:   lib1/l1, main/m, main/m.export, main
STEP 1:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l1, lib1/l1.export, lib1
STEP 2:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l2
STEP 3:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l2, lib1/l2.export, lib1
STEP 4:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1
STEP 5:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l1
STEP 6:
    libs: lib1, main
    dirty js modules: lib1
    dirty js files:   lib1/l1, lib1/l1.export, lib1/l2, lib1