Check stderr for subprocess call errors

autover/version.py

@@ -117,7 +117,10 @@ def run_cmd(args, cwd=None):
                             cwd=cwd)
     output, error = (str(s.decode()).strip() for s in proc.communicate())
 
-    if proc.returncode != 0:
+    # Detects errors as _either_ a non-zero return code _or_ messages
+    # printed to stderr, because the return code is erroneously fixed at 
+    # zero in some cases (see https://github.com/holoviz/param/pull/389).
+    if proc.returncode != 0 or len(error) > 0:
         raise Exception(proc.returncode, error)
     return output
 

examples/PkgBundle/version.py

@@ -117,7 +117,10 @@ def run_cmd(args, cwd=None):
                             cwd=cwd)
     output, error = (str(s.decode()).strip() for s in proc.communicate())
 
-    if proc.returncode != 0:
+    # Detects errors as _either_ a non-zero return code _or_ messages
+    # printed to stderr, because the return code is erroneously fixed at 
+    # zero in some cases (see https://github.com/holoviz/param/pull/389).
+    if proc.returncode != 0 or len(error) > 0:
         raise Exception(proc.returncode, error)
     return output
 

examples/pkg_bundle/version.py

@@ -117,7 +117,10 @@ def run_cmd(args, cwd=None):
                             cwd=cwd)
     output, error = (str(s.decode()).strip() for s in proc.communicate())
 
-    if proc.returncode != 0:
+    # Detects errors as _either_ a non-zero return code _or_ messages
+    # printed to stderr, because the return code is erroneously fixed at 
+    # zero in some cases (see https://github.com/holoviz/param/pull/389).
+    if proc.returncode != 0 or len(error) > 0:
         raise Exception(proc.returncode, error)
     return output