kernelci: config: reduce noise during config parsing

When loading configuration files for the first time, the current job
isn't configured yet and we're missing important params such as the
target architecture. However, we try to parse and format every single
string from the config, leading to numerous errors being printed to the
console.

As those are `KeyError` exceptions, we should process them separately
and only print a message for other types of exceptions.

Fixes #2988

Signed-off-by: Arnaud Ferraris <arnaud.ferraris@collabora.com>

Author: a-wai

kernelci/config/base.py

@@ -73,9 +73,15 @@ def _format_dict_strings(param, fmap):
     if isinstance(param, str):
         try:
             param = param.format_map(fmap)
-        except (KeyError, ValueError) as exc:
-            print(f"Format string error in param '{param}': {exc}")
+        # Upon loading the config files, we go through lots of fields (e.g. `nfsroot`)
+        # that contain unresolved params (such as `debarch` or `kver`) as we're not
+        # processing a job yet. In such cases, format_map() returns a KeyError we can
+        # just ignore.
+        except KeyError:
             return param  # Don't do anything but keep python happy
+        except ValueError as exc:
+            print(f"Format string error in param '{param}': {exc}")
+            return param  # Return the unformatted param, this will help spot the error
     elif isinstance(param, dict):
         for key in param:
             param[key] = _format_dict_strings(param[key], fmap)