Try a backup copy if the downloaded cutechess-cli is not working.

Logic:

1) Check if cutechess-cli exists and is working.

2) If not: download it.

3) Check if downloaded cutechess-cli is working.

4) If not: try to restore a backup copy.

5) If successful check if the backup copy is working.

6) If not: bail out.

Do not treat MacOS specially in the updater.

worker/games.py

@@ -257,7 +257,7 @@ def required_net(engine):
     return net
 
 
-def verify_required_cutechess(testing_dir, cutechess):
+def verify_required_cutechess(testing_dir, cutechess, quiet=False):
     print(
         "Obtaining version info for {} ...".format(os.path.join(testing_dir, cutechess))
     )
@@ -282,22 +282,27 @@ def verify_required_cutechess(testing_dir, cutechess):
                     minor = int(m.group(2))
                     patch = int(m.group(3))
     except (OSError, subprocess.SubprocessError) as e:
-        raise FatalException("Unable to run cutechess-cl. Error: {}".format(str(e)))
+        if not quiet:
+            print("Unable to run cutechess-cli. Error: {}".format(str(e)))
+        return False
 
     if p.returncode != 0:
-        raise FatalException(
+        print(
             "Unable to run cutechess-cli. Return code: {}. Error: {}".format(
                 format_return_code(p.returncode), errors
             )
         )
+        return False
 
     if major + minor + patch == 0:
-        raise FatalException("Unable to find the version of cutechess-cli.")
+        print("Unable to find the version of cutechess-cli.")
+        return False
 
     if (major, minor) < (1, 2):
-        raise FatalException(
-            "Requires cutechess 1.2 or higher, found version doesn't match"
-        )
+        print("Requires cutechess 1.2 or higher, found version doesn't match")
+        return False
+
+    return True
 
 
 def required_net_from_source():
@@ -1143,7 +1148,7 @@ def run_games(worker_info, password, remote, run, task_id, pgn_file):
     if "start" in task:
         print("Variable task sizes used. Opening offset = {}".format(opening_offset))
     start_game_index = opening_offset + input_total_games
-    run_seed = int(hashlib.sha1(run["_id"].encode("utf-8")).hexdigest(), 16) % (2**30)
+    run_seed = int(hashlib.sha1(run["_id"].encode("utf-8")).hexdigest(), 16) % (2 ** 30)
 
     # Format options according to cutechess syntax.
     def parse_options(s):
@@ -1167,10 +1172,10 @@ def parse_options(s):
     if not os.path.exists(testing_dir):
         os.makedirs(testing_dir)
 
-    # Download cutechess if missing in the directory.
+    # Download cutechess if not working or missing in the directory.
     cutechess = "cutechess-cli" + EXE_SUFFIX
     os.chdir(testing_dir)
-    if not os.path.exists(cutechess):
+    if not verify_required_cutechess(testing_dir, cutechess, quiet=True):
         if len(EXE_SUFFIX) > 0:
             zipball = "cutechess-cli-win.zip"
         elif IS_MACOS:
@@ -1184,8 +1189,28 @@ def parse_options(s):
         os.remove(zipball)
         os.chmod(cutechess, os.stat(cutechess).st_mode | stat.S_IEXEC)
 
-    # Verify that cutechess is working and has the required minimum version.
-    verify_required_cutechess(testing_dir, cutechess)
+        # Verify that cutechess is working and has the required minimum version.
+        if not verify_required_cutechess(testing_dir, cutechess):
+            print(
+                "The downloaded cutechess-cli is not working. Trying to restore a backup copy ..."
+            )
+            bkp_cutechess_clis = sorted(
+                glob.glob(os.path.join(worker_dir, "_testing_*", cutechess)),
+                key=os.path.getctime,
+            )
+            if bkp_cutechess_clis:
+                bkp_cutechess_cli = bkp_cutechess_clis[-1]
+                shutil.copy(bkp_cutechess_cli, testing_dir)
+                if not verify_required_cutechess(testing_dir, cutechess):
+                    print(
+                        "The backup copy {} doesn't work either ...".format(
+                            bkp_cutechess_cli
+                        )
+                    )
+                    raise FatalException("No suitable cutechess-cli found")
+            else:
+                print("No backup copy found")
+                raise FatalException("No suitable cutechess-cli found")
 
     # Clean up old engines (keeping the num_bkps most recent).
     engines = glob.glob(os.path.join(testing_dir, "stockfish_*" + EXE_SUFFIX))

worker/updater.py

@@ -68,10 +68,6 @@ def update(restart=True, test=False):
         bkp_testing_dir = os.path.join(worker_dir, "_testing_" + time_stamp)
         shutil.move(testing_dir, bkp_testing_dir)
         os.makedirs(testing_dir)
-        # Copy the user built MacOS cutechess-cli
-        # until we will have an official MacOS build to download
-        if "darwin" in platform.system().lower():
-            shutil.copy2(os.path.join(bkp_testing_dir, "cutechess-cli"), testing_dir)
         # Delete old engine binaries
         engines = glob.glob(os.path.join(bkp_testing_dir, "stockfish_*"))
         for engine in engines: