Inline `io.read_doc` and explain why settings are copied

1 files changed, 2 insertions, 17 deletions

diff --git a/sphinx/io.py b/sphinx/io.py
index 4ffa8e54d..b4cec7d3e 100644
--- a/sphinx/io.py
+++ b/sphinx/io.py
@@ -1,5 +1,5 @@
 """Input/Output files"""
-import codecs
+
 from typing import TYPE_CHECKING, Any, List, Type
 
 from docutils import nodes
@@ -19,7 +19,7 @@ from sphinx.transforms import (AutoIndexUpgrader, DoctreeReadEvent, FigureAligne
 from sphinx.transforms.i18n import (Locale, PreserveTranslatableMessages,
                                     RemoveTranslatableInline)
 from sphinx.transforms.references import SphinxDomains
-from sphinx.util import UnicodeDecodeErrorHandler, logging
+from sphinx.util import logging
 from sphinx.util.docutils import LoggingReporter
 from sphinx.versioning import UIDTransform
 
@@ -152,21 +152,6 @@ class SphinxFileInput(FileInput):
         super().__init__(*args, **kwargs)
 
 
-def read_doc(publisher: Publisher, docname: str, filename: str) -> nodes.document:
-    """Parse a document and convert to doctree."""
-    # set up error_handler for the target document
-    error_handler = UnicodeDecodeErrorHandler(docname)
-    codecs.register_error('sphinx', error_handler)  # type: ignore
-
-    publisher.set_source(source_path=filename)
-    publisher.publish()
-
-    doctree = publisher.document
-    # settings get modified in ``write_doctree``; get a local copy
-    doctree.settings = doctree.settings.copy()
-    return doctree
-
-
 def create_publisher(app: "Sphinx", filetype: str) -> Publisher:
     reader = SphinxStandaloneReader()
     reader.setup(app)