Blog plugin should raise warning, not error when related link target does not exist

[alexvoss]

Context

Building blogs with Insider edition and related links.

Bug description

When building a blog with related links that do not have a valid target (page or anchor), the blog plugin aborts the build with an error. Instead, it should create a warning so that in non-strict mode the build can finish.

Related links

• Reporting a bug
• https://squidfunk.github.io/mkdocs-material/setup/setting-up-a-blog/#adding-related-links
• https://www.mkdocs.org/user-guide/configuration/#strict

Reproduction

9.5.12+insiders.4.53.0-blog-related-links-should-respect-strictnon-strict.zip

Steps to reproduce

1. with Insiders, build reproduction project, observe build fail
2. change the link in the single blog post to a non-existing page instead of non-existing anchor, observe same behaviour

Browser

No response

Before submitting

• I have read and followed the bug reporting guidelines.
• I have attached links to the documentation, and possibly related issues and discussions.
• I assure that I have removed all customizations before submitting this bug report.
• I have attached a .zip file with a minimal reproduction using the built-in info plugin.

[squidfunk]

Thanks for reporting. We can investigate whether we can change this to a warning, but I'm not sure if this is easily achievable. Please note that this is currently not a priority and we're considering it an edge case, but we can look into it for sure ☺️

[squidfunk]

Fixed in 519170d. Unresolvable links will now just be left as-is and a warning is printed:

INFO    -  Building documentation...
INFO    -  Cleaning site directory
WARNING -  Error reading metadata of post 'blog/posts/test.md' in 'docs':
           Couldn't find anchor 'does-not-exist' in 'index.md'
WARNING -  Error reading metadata of post 'blog/posts/test.md' in 'docs':
           Couldn't find file for link 'foo.md'
INFO    -  Documentation built in 0.15 seconds

[squidfunk]

Released as part of 9.5.13+insiders-4.53.1.