Automatically create parent Directory entries for each discovery

Before this change it was possible for a file and a directory have the
same path. This change resolves that. Conflicts between files and
directories are now correctly discovered.

omicron/ssg/site.py

@@ -4,8 +4,10 @@ from urllib.parse import urlparse
 
 from omicron.ssg.output import (
     Output,
+    OutputError,
     Content,
     ContentError,
+    Directory,
     is_content,
     create_content,
     File,
@@ -32,6 +34,7 @@ class Site:
     def __init__(self, site: Path):
         self.site_path = site.absolute()
         self.content: list[Content] = []
+        self.directories: list[Directory] = []
         self.other_outputs: list[Output] = []
         self.by_tag: dict[str, list[Content]] = {}
         self.by_path: dict[Path, Output] = {}
@@ -98,7 +101,23 @@ class Site:
             raise ContentError(
                 f"path '{output.destination}' is already claimed by another output"
             )
+        new_dirs: list[Directory] = []
+        for parent in output.destination.parents:
+            if parent == Path("."):
+                break
+            if parent in self.by_path:
+                if not isinstance(self.by_path[parent], Directory):
+                    raise OutputError(
+                        f"path '{parent}' is claimed by a file but needed as a directory"
+                    )
+                break
+            new_dirs.append(Directory(self, parent))
         self.by_path[output.destination] = output
+        if isinstance(output, Directory):
+            self.directories.append(output)
+        for d in new_dirs:
+            self.by_path[d.destination] = d
+            self.directories.append(d)
 
     def home_url(self) -> str:
         return self.base_dir or "/"
@@ -163,8 +182,8 @@ class Site:
         if self.base_dir and not self.base_dir.startswith("/"):
             raise ConfigError("base_url config value must be an absolute path")
         self.discover()
-        self.output_path.mkdir(parents=True, exist_ok=True)
-        for content in self.content:
-            content.write()
+        outputs: list[Output] = [*self.directories, *self.content]
+        for output in sorted(outputs, key=lambda o: o.destination.as_posix()):
+            output.write()
         for output in self.other_outputs:
             output.write()