[Change Request] Allow plugins to edit metadata before on_page_markdown

[McDic]

Hello.

I was building a plugin which tracks git history of a file on non-metadata lines. I wanted to track only content edit history, not metadata edit history. But I realized self.meta is overrided by meta.get_date in following lines;

mkdocs/mkdocs/structure/pages.py

Lines 202 to 215 in 7186f4c

	def read_source(self, config: MkDocsConfig) -> None:
	source = config.plugins.on_page_read_source(page=self, config=config)
	if source is None:
	try:
	with open(self.file.abs_src_path, encoding='utf-8-sig', errors='strict') as f:
	source = f.read()
	except OSError:
	log.error(f'File not found: {self.file.src_path}')
	raise
	except ValueError:
	log.error(f'Encoding error reading file: {self.file.src_path}')
	raise
	self.markdown, self.meta = meta.get_data(source)

Therefore I request mkdocs to change this behavior. I can upload pull requests myself if you want.

[tomchristie]

Therefore I request mkdocs to change this behavior.

It's not very clear to me exactly what you're suggesting, perhaps you could provide an example from the perspective of how the docs should look/function? (Rather than from the perspective of the code)

[McDic]

Not sure how can I describe this without perspective of the code, but ok.

Some plugins might want to change metadata of the post before on_read_source. mkdocs is wiping out every custom change on self.meta when it read the raw source of markdown files. Therefore, my plugin is adding custom metadata on on_page_markdown.

[pawamoy]

Some plugins might want to change metadata of the post before on_read_source.

Why would they want that? Could you describe your use-case?

Therefore, my plugin is adding custom metadata on on_page_markdown.

Is that not the solution?

Also, I can't seem to correlate your last comment with your initial description. IIUC, you want to track changes in the contents of Markdown documents, excluding metadata, so I'm not sure to understand why you'd want to change the metadata.

[kamilkrzyskow]

Git history is in the file system. It's not affected by changes in the event cycle internal to MkDocs, unless you write the changes to the file system in your plugin.
Therefore I'm not sure if the metadata change is the issue here.
Perhaps provide a more specific example?