fix: stable YAML schema generation (#3388)

* add key sorting in schema generation

* add pre-commit hook

* try pre-commit hook

* Fixed schemas

* trying a simpler version

* pylint

* ordered dict

* reverting to dict

* unused import

* remove hook

.pre-commit-config.yaml

@@ -14,7 +14,6 @@ repos:
     - id: check-shebang-scripts-are-executable  # checks all shell scripts have executable permissions
     - id: mixed-line-ending  # normalizes line endings
     - id: no-commit-to-branch  # prevents committing to main
-    #- id: pretty-format-json  # indents and sorts JSON files    # FIXME: JSON schema generator conflicts with this
 
 - repo: https://github.com/psf/black
   rev: 22.6.0  # IMPORTANT: keep this aligned with the black version in pyproject.toml

haystack/nodes/_json_schema.py

@@ -380,6 +380,9 @@ def get_json_schema(filename: str, version: str, modules: List[str] = ["haystack
         ],
         "definitions": schema_definitions,
     }
+
+    # Leveraging an implementation detail of dict: keys stay in the order they are inserted.
+    pipeline_schema = dict(sorted(pipeline_schema.items(), key=lambda pair: pair[0]))
     return pipeline_schema
 
 
@@ -435,4 +438,4 @@ def update_json_schema(destination_path: Path = JSON_SCHEMAS_PATH):
         if new_entry not in index["oneOf"]:
             index["oneOf"].append(new_entry)
     with open(destination_path / index_name, "w") as json_file:
-        json.dump(index, json_file, indent=2)
+        json.dump(obj=index, fp=json_file, indent=2)