error handling

src/assets/config.schema.yaml

@@ -25,10 +25,10 @@ $defs:
       $ref: "#/$defs/font-variation"
 
   css:
-    # https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face#descriptors
     type: object
     additionalProperties: false
     patternProperties:
+      # https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face#descriptors
       ? "^ascent-override|descent-override|font-display|font-family|font-stretch|font-style|font-weight|font-feature-settings|font-variation-settings|line-gap-override|size-adjust|src|unicode-range$"
       : type: string
 

src/cmd_optimise.py

@@ -1,4 +1,3 @@
-import copy
 import hashlib
 import json
 import os

src/main.py

@@ -1,5 +1,6 @@
 
 import click
+import jsonschema
 
 import cmd_optimise
 import flags
@@ -24,7 +25,12 @@ def cli(verbose, config, output_directory, clean, prefix):
 
     # Run
     c = load(config)
+    try:
         validate(c)
+    except jsonschema.exceptions.ValidationError as e:
+        click.echo(f"Config validation failed:")
+        click.echo(f"{e.message} @ {e.json_path}")
+        exit(1)
     cmd_optimise.optimise(c)