Ensure that author preamble has handle or email

src/error.rs

@@ -40,6 +40,7 @@ pub enum Error {
     UnmatchedEmailDelimiter,
     UnmatchedHandleDelimiter,
     AuthorHasEmailAndHandle,
+    AuthorHasNoContactDetails,
     TrailingInfoAfterEmail,
     TrailingInfoAfterHandle,
     MalformedEmail,
@@ -98,6 +99,7 @@ impl Error {
             Self::UnmatchedEmailDelimiter => "unmatched email delimiter",
             Self::UnmatchedHandleDelimiter => "unmatched handle delimiter",
             Self::AuthorHasEmailAndHandle => "author can't include both an email and handle",
+            Self::AuthorHasNoContactDetails => "author has no contact details",
             Self::TrailingInfoAfterEmail => "trailing information after email",
             Self::TrailingInfoAfterHandle => "trailing information after handle",
             Self::MalformedEmail => "malformed email",

src/validators.rs

@@ -141,6 +141,10 @@ fn validate_author<'a>(acc: &mut Vec<String>, s: &str) -> Result<()> {
         return Err(Error::AuthorHasEmailAndHandle);
     }
 
+    if email_start.is_some() == false && handle_start.is_some() == false {
+        return Err(Error::AuthorHasNoContactDetails);
+    }
+
     if email_start.is_some() {
         let start = email_start.unwrap();
         let end = email_end.unwrap();

tests/fixtures/preamble-author-no-contact.md

@@ -0,0 +1,39 @@
+---
+eip: 1
+title: A sample proposal
+author: John Doe
+discussions-to: https://example.com
+status: Draft
+type: Standards Track
+category: Core
+created: 2020-01-01
+updated: 2020-01-01
+requires: 20, 1337, 2048
+---
+
+## Abstract
+This is the abstract for the EIP.
+
+## Motivation
+This is the motivation for the EIP.
+
+## Specification
+This is the specification for the EIP.
+
+## Rationale
+This is the rationale for the EIP.
+
+## Backwards Compatibility
+These are the backwards compatibility concerns for the EIP.
+
+## Test Cases
+These are the test cases for the EIP.
+
+## Implementation
+This is the implementation for the EIP.
+
+## Security Considerations
+These are the security considerations for the EIP.
+
+## Copyright
+Copyright and related rights waived via [CC0](https://creativecommons.org/publicdomain/zero/1.0/).

tests/tests.rs

@@ -158,6 +158,10 @@ fn preamble_author() {
     );
     test_fixture("preamble-author-email-invalid.md", "malformed email");
     test_fixture("preamble-author-handle-invalid.md", "malformed handle");
+    test_fixture(
+        "preamble-author-no-contact.md",
+        "author has no contact details",
+    );
 }
 
 #[test]