Improve cask audit

[apainintheneck]

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---

Another follow-up to #15943 and #15956.

• check for cask.url in audit steps
• check for cask.version in audit steps
• check for cask.sha256 in fetch command
• stop omitting casks based on nil url in audit command

It would be nice to be able to omit casks from the audit if the os is not supported but there is not easy way to do that without updating the SimulateSystem code or refactoring how MacOSRequirement's are defined in the DSL.

At the end of the day, these changes make it so that you won't try to fetch a cask if the url or sha256 is missing (we'd expect the sha256 value to be :no_check if it's been omitted on purpose). It also allows the audit to accept casks with nil urls and versions since we already check for those. The problem was that we had some audit steps which assumed those values would be valid (non-nil) and now they don't.

Results for brew audit --skip-style homebrew/cask/calhash -os=all --debug

/usr/local/Homebrew/Library/Homebrew/brew.rb (Formulary::TapLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Formula/calhash.rb
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapLoader): loading homebrew/cask/calhash
==> Auditing Cask calhash on os sonoma and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing version :latest does not appear as a string ('latest')
==> Auditing sha256 :no_check with version :latest
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing URL format
==> Auditing GitHub prerelease
==> Auditing Cask calhash on os ventura and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing version :latest does not appear as a string ('latest')
==> Auditing sha256 :no_check with version :latest
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing URL format
==> Auditing GitHub prerelease
==> Auditing Cask calhash on os monterey and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing version :latest does not appear as a string ('latest')
==> Auditing sha256 :no_check with version :latest
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing URL format
==> Auditing GitHub prerelease
==> Auditing Cask calhash on os big_sur and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing version :latest does not appear as a string ('latest')
==> Auditing sha256 :no_check with version :latest
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing URL format
==> Auditing GitHub prerelease
==> Auditing Cask calhash on os catalina and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing version :latest does not appear as a string ('latest')
==> Auditing sha256 :no_check with version :latest
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing URL format
==> Auditing GitHub prerelease
==> Auditing Cask calhash on os mojave and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing GitHub prerelease
audit for calhash: failed
 - a version stanza is required
 - a url stanza is required
==> Auditing Cask calhash on os high_sierra and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing GitHub prerelease
audit for calhash: failed
 - a version stanza is required
 - a url stanza is required
==> Auditing Cask calhash on os sierra and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing GitHub prerelease
audit for calhash: failed
 - a version stanza is required
 - a url stanza is required
==> Auditing Cask calhash on os el_capitan and arch intel
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromTapPathLoader): loading /usr/local/Homebrew/Library/Taps/homebrew/homebrew-cask/Casks/c/calhash.rb
==> Auditing pkg stanza: allow_untrusted
==> Auditing stanzas which require an uninstall
==> Auditing preflight and postflight stanzas
==> Auditing single uninstall_* and zap stanzas
==> Auditing required stanzas
==> Auditing sha256 string is a legal SHA-256 digest
==> Auditing sha256 is not a known invalid value
==> Auditing GitHub prerelease
audit for calhash: failed
 - a version stanza is required
 - a url stanza is required
calhash
  * a version stanza is required
  * a url stanza is required
Error: 2 problems in 1 cask detected.

[apainintheneck]

@EricFromCanada Does this seem reasonable?

[MikeMcQuaid]

Makes sense to me and would be good to fix affected casks.

[EricFromCanada]

Makes sense from here 👍

[apainintheneck]

I guess I should check if a nil cask.homepage is accounted for too.

brew/Library/Homebrew/cask/audit.rb

Line 185 in 12c8778

[:version, :sha256, :url, :homepage].each do |sym|

[EricFromCanada]

I guess I should check if a nil cask.homepage is accounted for too.

Depends on how likely is it for a cask's homepage to vary depending on the version it installs.

[apainintheneck]

I added a two more online only ones. There are probably a few more out there but we can fix them as they come up.

[MikeMcQuaid]

Thanks again @apainintheneck!