Some URL-safe special characters cannot be used in Page path

[trwnh]

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

$ hugo version
hugo v0.136.5+extended linux/amd64 BuildDate=unknown

Does this issue reproduce with the latest release?

yes

Steps to reproduce

1. Add a page (e.g. using a content adapter) whose path includes an exclamation mark (e.g. yu-gi-oh!)

Expected behavior

The page is created with the url including the exclamation mark (e.g. /tags/yu-gi-oh!)

Actual behavior

The exclamation mark seems to be sanitized out (e.g. /tags/yu-gi-oh, creating a path conflict with an already existing page)

Additional information

https://gohugo.io/methods/page/path/ describes the following:

To determine the logical path for pages backed by a file, Hugo starts with the file path, relative to the content directory, and then:

• Strips the file extension
• Strips the language identifier
• Converts the result to lower case
• Replaces spaces with hyphens

The value returned by the Path method on a Page object is independent of content format, language, and URL modifiers such as the slug and url front matter fields.

Nowhere in these 4 steps does it say anything about removing URL-safe characters entirely. This issue seems to occur for some URL-safe characters, but not all. These are the ones that work:

• content/foo-bar.md => /foo-bar/ (correct).
• content/foo_bar.md => /foo_bar/ (correct).
• content/foo.bar.md => /foo.bar/ (correct).
• content/foo+bar.md => /foo+bar/ (correct).
• content/foo@bar.md => /foo@bar/ (correct).
• content/foo~bar.md => /foo~bar/ (correct).

And these are the ones that don't work:

• content/foo$bar.md => /foobar/ (incorrect). /foo$bar/ leads to a Page Not Found.
• content/foo!bar.md => /foobar/ (incorrect). /foo!bar/ leads to a Page Not Found.
• content/foo*bar.md => /foobar/ (incorrect). /foo*bar/ leads to a Page Not Found.
• content/foo'bar.md => /foobar/ (incorrect). /foo'bar/ leads to a Page Not Found.
• content/foo(bar.md => /foobar/ (incorrect). /foo(bar/ leads to a Page Not Found.
• content/foo)bar.md => /foobar/ (incorrect). /foo)bar/ leads to a Page Not Found.
• content/foo;bar.md => /foobar/ (incorrect). /foo;bar/ leads to a Page Not Found.
• content/foo=bar.md => /foobar/ (incorrect). /foo=bar/ leads to a Page Not Found.
• content/foo:bar.md => /foobar/ (incorrect). /foo:bar/ leads to a Page Not Found.
• content/foo[bar.md => /foobar/ (incorrect). /foo[bar/ leads to a Page Not Found.
• content/foo]bar.md => /foobar/ (incorrect). /foo]bar/ leads to a Page Not Found.
• content/foo&bar.md => /foobar/ (incorrect). /foo&bar/ leads to a Page Not Found.
• content/foo,bar.md => /foobar/ (incorrect). /foo,bar/ leads to a Page Not Found.

Again, I would expect that URL-safe characters are preserved, because there is nothing to suggest that they should be removed. Out of the "reserved" characters per the URI RFC (: / ? # [ ] @ ! $ & ' ( ) * + , ; =), we can probably eliminate characters that have special semantics in HTTP(S), like / for path segment separation, ? for query components, and # for fragment components. But most everything else should be fine to use in the path component. It feels weird to allow + or @, but not ! or $.

Example URLs with special characters in them:

• https://en.wikipedia.org/wiki/Yu-Gi-Oh!
• https://en.wikipedia.org/wiki/$h*!_My_Dad_Says

  • The correct title of this article is $#*! My Dad Says. The substitution of the # is due to technical restrictions.

Proposed resolution

Stop removing URL-safe characters from the Page.path, or at least make it clear (or better yet, configurable) which characters will be removed and which ones won't.