fix(empty transient data): Empty first stress period block (#1091) (#2139)

* fix(empty transient data): empty stress period 1 transient data is now retained and used to create empty stress period block (#1091)

* fix(empty transient data)

---------

Co-authored-by: scottrp <[email protected]>

Author: spaulins-usgs

autotest/regression/test_mf6.py

@@ -751,7 +751,7 @@ def test_np001(function_tmpdir, example_data_path):
                 found_cellid = True
     assert found_cellid
 
-    # test empty stress period
+    # test empty stress period and remove output
     well_spd = {0: [(-1, -1, -1, -2000.0), (0, 0, 7, -2.0)], 1: []}
     wel_package = ModflowGwfwel(
         model,
@@ -763,6 +763,13 @@ def test_np001(function_tmpdir, example_data_path):
         maxbound=2,
         stress_period_data=well_spd,
     )
+    oc_package = ModflowGwfoc(
+        model,
+        budget_filerecord=[("np001_mod 1.cbc",)],
+        head_filerecord=[("np001_mod 1.hds",)],
+        saverecord={0: []},
+        printrecord={0: []},
+    )
     sim.write_simulation()
     found_begin = False
     found_end = False
@@ -787,6 +794,10 @@ def test_np001(function_tmpdir, example_data_path):
         spath,
         write_headers=False,
     )
+    # test to make sure oc empty record dictionary is set
+    oc = test_sim.get_model().get_package("oc")
+    assert oc.saverecord.empty_keys[0] is True
+    # test wel package
     wel = test_sim.get_model().get_package("wel_2")
     wel._filename = "np001_spd_test.wel"
     wel.write()

flopy/mf6/data/mfdatalist.py

@@ -1745,6 +1745,9 @@ def has_data(self, key=None):
                 self.get_data_prep(sto_key)
                 if super().has_data():
                     return True
+            for val in self.empty_keys.values():
+                if val:
+                    return True
             return False
         else:
             self.get_data_prep(key)

flopy/mf6/mfpackage.py

@@ -1031,6 +1031,13 @@ def load(self, block_header, fd, strict=True):
                                 and result[1][:3].upper() == "END"
                             ):
                                 break
+        else:
+            # block empty, store empty array in block variables
+            empty_arr = []
+            for ds in self.datasets.values():
+                if isinstance(ds, mfdata.MFTransient):
+                    transient_key = block_header.get_transient_key()
+                    ds.set_data(empty_arr, transient_key)
         self.loaded = True
         self.is_valid()
 
@@ -2976,7 +2983,7 @@ def _load_blocks(self, fd_input_file, strict=True, max_blocks=sys.maxsize):
                             block_header_info, fd_input_file, strict
                         )
 
-                        # write post block comment comment
+                        # write post block comment
                         self._simulation_data.mfdata[
                             cur_block.block_headers[-1].blk_post_comment_path
                         ] = self.post_block_comments