[Obsidian 1.8.5] app.fileManager.processFrontMatter stop working

[Mara-Li]

Plugin Information

• OS: Windows 11
• Templater version: 2.9.3
• Obsidian version: 1.8.5
• Templater settings: Default

Describe the Bug

When using the following code:

<%* 
	const file = tp.file.find_tfile(tp.file.title); 
	await tp.app.fileManager.processFrontMatter(file, (frontmatter) => {
		frontmatter["key"] = "U"; 
	}); 
%>

The frontmatter does not get updated. Instead, it appears to be modified and then immediately reverted, as if Obsidian restores the file's original contents.

Expected Behavior

The frontmatter should be updated with the new key-value pair.

Screenshots

Screen recording

Additional Context

The issue is reproducible in Obsidian's sandbox mode.

[Zachatoo]

I can reproduce when using the "replace templates in the active file" command, but not the "open insert template modal" command, which is the more commonly used command. Are you seeing the same? Do you have a use case for "replace template in the active file" outside of testing?

I am also on Obsidian 1.8.5, Templater 2.9.3.

[Mara-Li]

I use mostly "replace templates in the active file" than open insert template modal :'). I have even a quick shortcuts for it, so i can write template and quick replace the text.

[Zachatoo]

In that case, I can recommend the following.

<%* 
const file = tp.file.find_tfile(tp.file.title); 
await tp.hooks.on_all_templates_executed(async () => {
  await tp.app.fileManager.processFrontMatter(file, (frontmatter) => {
    frontmatter["key"] = "T"; 
  });
});
-%>

Let me know if that doesn't work and I'm happy to explore more options with you!

Closing since I don't expect we'll be able to fix the original issue, and will instead rely on this workaround.

[Mara-Li]

Thank you! It was what I have done when discovering the hook :)