How to write metadata with indentation?

[Guts]

Thanks for this useful package!

I'm using it to homogenize YAML frontmatter through thousands of Markdown files but I can't figure out how to keep the source file indentation (to 4):

Input Markdown:

---
date: 2023-05-12
title: Sample
tags:
    - test
    - sample
---

# Title 1

Script:

[...]
# write new version
with md_filepath.open(mode="w", encoding="UTF-8") as out_file:
    # frontmatter.dump(content, out_file) # not working, using workaround
    out_file.write(
        frontmatter.dumps(content, sort_keys=False, **{"indent": 4})
    )

Output Markdown:

See tags values

---
processed: true
date: 2023-05-12
title: Sample
tags:
- test
- sample
---

# Title 1

[PLRrex]

Perhaps I'm too late to answer, but I tested the following code I adapted from this answer at stackoverflow with your input markdown and it seems to work.

import frontmatter
import yaml

class MyDumper(yaml.Dumper):
    def increase_indent(self, flow=False, indentless=False):
        return super(MyDumper, self).increase_indent(flow, False)

# code to read input here goes here

# write new version
with open(mode="w", encoding="UTF-8") as out_file:
    out_file.write(
        frontmatter.dumps(content, sort_keys=False, width=5000, Dumper=MyDumper, default_flow_style=False, indent=4)
    )

(The width=5000 is a nice trick you may find useful if some of your yaml values are longer than the default line width, resulting in them being undesirably wrapped to multiple lines, but that's another story.)

Also, I don't know why, but out of curiosity I tried changing indent=4 to something extreme like indent=20 and it goes back to the default(?) value of indenting 2 spaces, so perhaps the above code has some bugs hidden somewhere.