fix: skip missing artifacts in pre-release

Author: upsetbit

pre-release-steps.py

@@ -37,6 +37,9 @@ def download_and_write(filename):
     url = 'https://github.com/vrelease/vrelease/releases/download/v{}/{}'.format(VERSION, filename)
 
     req = requests.get(url, stream=True, timeout=30)
+    if req.status_code == 404:
+        log('missing artifact: ' + filename)
+        return None
     req.raise_for_status()
     with tempfile.NamedTemporaryFile(delete=False, dir=dirname(dest_path)) as tmp_file:
         for chunk in req.iter_content(chunk_size=8192):
@@ -73,6 +76,9 @@ def main():
             'windows.exe',
         ]
     ]
+    files = [file for file in files if file]
+    if not files:
+        raise RuntimeError('no artifacts downloaded')
 
     log('calculating hashes')
     shasum = []