rework extensions metadata: use custom sorter that doesn't mess the order as much and ignores cyclic errors, use classes with named fields instead of dictionaries, eliminate some duplicated code

modules/extensions.py

@@ -1,5 +1,6 @@
+from __future__ import annotations
+
 import configparser
-import functools
 import os
 import threading
 import re
@@ -8,7 +9,6 @@ from modules import shared, errors, cache, scripts
 from modules.gitpython_hack import Repo
 from modules.paths_internal import extensions_dir, extensions_builtin_dir, script_path  # noqa: F401
 
-extensions = []
 
 os.makedirs(extensions_dir, exist_ok=True)
 
@@ -22,13 +22,56 @@ def active():
         return [x for x in extensions if x.enabled]
 
 
+class ExtensionMetadata:
+    filename = "metadata.ini"
+    config: configparser.ConfigParser
+    canonical_name: str
+    requires: list
+
+    def __init__(self, path, canonical_name):
+        self.config = configparser.ConfigParser()
+
+        filepath = os.path.join(path, self.filename)
+        if os.path.isfile(filepath):
+            try:
+                self.config.read(filepath)
+            except Exception:
+                errors.report(f"Error reading {self.filename} for extension {canonical_name}.", exc_info=True)
+
+        self.canonical_name = self.config.get("Extension", "Name", fallback=canonical_name)
+        self.canonical_name = canonical_name.lower().strip()
+
+        self.requires = self.get_script_requirements("Requires", "Extension")
+
+    def get_script_requirements(self, field, section, extra_section=None):
+        """reads a list of requirements from the config; field is the name of the field in the ini file,
+        like Requires or Before, and section is the name of the [section] in the ini file; additionally,
+        reads more requirements from [extra_section] if specified."""
+
+        x = self.config.get(section, field, fallback='')
+
+        if extra_section:
+            x = x + ', ' + self.config.get(extra_section, field, fallback='')
+
+        return self.parse_list(x.lower())
+
+    def parse_list(self, text):
+        """converts a line from config ("ext1 ext2, ext3  ") into a python list (["ext1", "ext2", "ext3"])"""
+
+        if not text:
+            return []
+
+        # both "," and " " are accepted as separator
+        return [x for x in re.split(r"[,\s]+", text.strip()) if x]
+
+
 class Extension:
     lock = threading.Lock()
     cached_fields = ['remote', 'commit_date', 'branch', 'commit_hash', 'version']
+    metadata: ExtensionMetadata
 
-    def __init__(self, name, path, enabled=True, is_builtin=False, canonical_name=None):
+    def __init__(self, name, path, enabled=True, is_builtin=False, metadata=None):
         self.name = name
-        self.canonical_name = canonical_name or name.lower()
         self.path = path
         self.enabled = enabled
         self.status = ''
@@ -40,18 +83,8 @@ class Extension:
         self.branch = None
         self.remote = None
         self.have_info_from_repo = False
-
-    @functools.cached_property
-    def metadata(self):
-        if os.path.isfile(os.path.join(self.path, "metadata.ini")):
-            try:
-                config = configparser.ConfigParser()
-                config.read(os.path.join(self.path, "metadata.ini"))
-                return config
-            except Exception:
-                errors.report(f"Error reading metadata.ini for extension {self.canonical_name}.",
-                              exc_info=True)
-        return None
+        self.metadata = metadata if metadata else ExtensionMetadata(self.path, name.lower())
+        self.canonical_name = metadata.canonical_name
 
     def to_dict(self):
         return {x: getattr(self, x) for x in self.cached_fields}
@@ -162,7 +195,7 @@ def list_extensions():
     elif shared.opts.disable_all_extensions == "extra":
         print("*** \"Disable all extensions\" option was set, will only load built-in extensions ***")
 
-    extension_dependency_map = {}
+    loaded_extensions = {}
 
     # scan through extensions directory and load metadata
     for dirname in [extensions_builtin_dir, extensions_dir]:
@@ -175,55 +208,30 @@ def list_extensions():
                 continue
 
             canonical_name = extension_dirname
-            requires = None
-
-            if os.path.isfile(os.path.join(path, "metadata.ini")):
-                try:
-                    config = configparser.ConfigParser()
-                    config.read(os.path.join(path, "metadata.ini"))
-                    canonical_name = config.get("Extension", "Name", fallback=canonical_name)
-                    requires = config.get("Extension", "Requires", fallback=None)
-                except Exception:
-                    errors.report(f"Error reading metadata.ini for extension {extension_dirname}. "
-                                  f"Will load regardless.", exc_info=True)
-
-            canonical_name = canonical_name.lower().strip()
+            metadata = ExtensionMetadata(path, canonical_name)
 
             # check for duplicated canonical names
-            if canonical_name in extension_dependency_map:
-                errors.report(f"Duplicate canonical name \"{canonical_name}\" found in extensions "
-                              f"\"{extension_dirname}\" and \"{extension_dependency_map[canonical_name]['dirname']}\". "
-                              f"The current loading extension will be discarded.", exc_info=False)
+            already_loaded_extension = loaded_extensions.get(metadata.canonical_name)
+            if already_loaded_extension is not None:
+                errors.report(f'Duplicate canonical name "{canonical_name}" found in extensions "{extension_dirname}" and "{already_loaded_extension.name}". Former will be discarded.', exc_info=False)
                 continue
 
-            # both "," and " " are accepted as separator
-            requires = list(filter(None, re.split(r"[,\s]+", requires.lower()))) if requires else []
-
-            extension_dependency_map[canonical_name] = {
-                "dirname": extension_dirname,
-                "path": path,
-                "requires": requires,
-            }
+            is_builtin = dirname == extensions_builtin_dir
+            extension = Extension(name=extension_dirname, path=path, enabled=extension_dirname not in shared.opts.disabled_extensions, is_builtin=is_builtin, metadata=metadata)
+            extensions.append(extension)
+            loaded_extensions[canonical_name] = extension
 
     # check for requirements
-    for (_, extension_data) in extension_dependency_map.items():
-        dirname, path, requires = extension_data['dirname'], extension_data['path'], extension_data['requires']
-        requirement_met = True
-        for req in requires:
-            if req not in extension_dependency_map:
-                errors.report(f"Extension \"{dirname}\" requires \"{req}\" which is not installed. "
-                              f"The current loading extension will be discarded.", exc_info=False)
-                requirement_met = False
-                break
-            dep_dirname = extension_dependency_map[req]['dirname']
-            if dep_dirname in shared.opts.disabled_extensions:
-                errors.report(f"Extension \"{dirname}\" requires \"{dep_dirname}\" which is disabled. "
-                              f"The current loading extension will be discarded.", exc_info=False)
-                requirement_met = False
-                break
+    for extension in extensions:
+        for req in extension.metadata.requires:
+            required_extension = loaded_extensions.get(req)
+            if required_extension is None:
+                errors.report(f'Extension "{extension.name}" requires "{req}" which is not installed.', exc_info=False)
+                continue
 
-        is_builtin = dirname == extensions_builtin_dir
-        extension = Extension(name=dirname, path=path,
-                              enabled=dirname not in shared.opts.disabled_extensions and requirement_met,
-                              is_builtin=is_builtin)
-        extensions.append(extension)
+            if not extension.enabled:
+                errors.report(f'Extension "{extension.name}" requires "{required_extension.name}" which is disabled.', exc_info=False)
+                continue
+
+
+extensions: list[Extension] = []