The following code is present in the hugo-coder template at head:

<meta name="description" content="{{ .Description | default (.Summary | default .Site.Params.description ) }}">

In version hugo v0.143.1-0270364a347b2ece97e0321782b21904db515ecc+extended linux/amd64 BuildDate=2025-02-04T08:57:38Z VendorInfo=gohugoio the hugo-coder exampleSite builds successfully. (https://github.com/simonhollingshead/hugo-coder/actions/runs/13362095239)

In version hugo v0.144.0-b289b17c433aa8ebf8c73ebbaf4bed973ac8e4d5+extended linux/amd64 BuildDate=2025-02-17T16:22:31Z VendorInfo=gohugoio this now fails (https://github.com/simonhollingshead/hugo-coder/actions/runs/13382377851) with the error

Error: error building site: render: failed to render pages: render of
"/home/runner/work/hugo-coder/hugo-coder/exampleSite/content/posts/more-rich-content.md" failed:
"/home/runner/work/hugo-coder/hugo-coder/layouts/_default/baseof.html:6:5": execute of template failed:
template: posts/single.html:6:5: executing "posts/single.html" at <partial "head.html" .>: error calling partial:
"/home/runner/work/hugo-coder/hugo-coder/layouts/partials/head.html:1:3": execute of template failed:
template: partials/head.html:1:3: executing "partials/head.html" at <partial "head/meta-tags.html" .>:
error calling partial: "/home/runner/work/hugo-coder/hugo-coder/layouts/partials/head/meta-tags.html:11:61":
execute of template failed: template: partials/head/meta-tags.html:11:61: executing
"partials/head/meta-tags.html" at <.Summary>: error calling Summary: interface conversion: interface {} is nil, not []uint8

I see nothing in the release notes indicating a breakage would be expected in this release, and this was not something that generated a warning in prior releases either. While I'm absolutely not ruling out the possibility that the code in the template is wrong, I was not expecting the permissiveness of the parser to handle it to change given the release notes as shown.

What version of Hugo are you using (hugo version)?

hugo v0.144.0-b289b17c433aa8ebf8c73ebbaf4bed973ac8e4d5+extended linux/amd64 BuildDate=2025-02-17T16:22:31Z VendorInfo=gohugoio

Does this issue reproduce with the latest release?

This is the latest release. The breakage appears to have occurred between 0.143.1 and 0.144.0.