[release/6.0] [mono] Use string.Empty for empty string custom arg values #58113
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Tagging subscribers to this area: Issue DetailsBackport of #58023 to release/6.0 /cc @lambdageek @uweigand Customer ImpactTestingRisk
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lambdageek
approved these changes
Aug 25, 2021
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Is a unit test infeasible? |
And not a new string object that happens to be `""` Adds a testcase for #58023
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Added a test. Also in #58197 for |
marek-safar
reviewed
Aug 27, 2021
| *out_obj = (MonoObject*)mono_string_new_wtf8_len_checked (p, slen, error); | ||
| // Always use string.Empty for empty strings | ||
| if (slen == 0) | ||
| *out_obj = (MonoObject*)mono_string_empty_internal (mono_domain_get ()); |
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nit: wouldn't mono_string_empty_wrapper be better?
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that one is marked MONO_RT_EXTERNAL_ONLY so cannot be used in runtime code.
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marek-safar
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Backport of #58023 to release/6.0
/cc @lambdageek @uweigand
Customer Impact
Discovered while running ASP.NET Core tests on the S390x port. Kestrel assumes that custom attribute values are reference-equal to
string.Empty, not some other empty string value.Testing
Manual testing and CI
Risk
Very low - code would have to rely on Mono's custom attribute implementation to return fresh string objects to be affected.