[RULE REQUEST] Check that non-empty strings are non-empty

[alexet]

Various parts of the spec specify non-empty strings but the validator accepts them. For example paragraphs 3.11.8, 3.11.9 and 3.11.10 (and more)

I am not sure about the metadata.

Rule metadata

• [Id] : [Should be formatted as SARIF1nnn, leave blank if unsure]

• Name : [Provide a friendly symbolic name for the rule in PascalCase.]

• Level : [Possible values are: error, warning, or note.]

• Full description : [Provide atleast two sentences. The first sentence should be a short description of the rule.
  This will appear as Short Description in rules metadata. The other sentence(s) should
  describe usage of the rule and any other relevant information.]

• User-facing strings:
  [Each rule has one or more result message strings, each with symbolic name in PascalCase.]

  • FirstMessage : [Default user facing string.]
  • [SecondMessage] : [Optional, Any conditional user facing string(s).]
  • [ThirdMessage] : [Optional, Any conditional user facing string(s).]

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Links/Additional Information

oasis-tcs/sarif-spec#543 suggests adding them to the schema so a separate rule may not be necessary if that happens.

How to resolve

Ensure that the string is non-empty