From: merch-redmine@...
Date: 2019-06-20T23:36:52+00:00
Subject: [ruby-core:93293] [Ruby trunk Feature#14278] Ambiguous Exception for OpenSSL::HMAC.digest

Issue #14278 has been updated by jeremyevans0 (Jeremy Evans).

Backport deleted (2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN)
ruby -v deleted (ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-linux-gnu])
Tracker changed from Bug to Feature

I do not think the current error message is a bug, and changing the message would be considered a feature.  In general, Ruby TypeError messages are not completely descriptive as to the argument and method names.  That is not specific to `OpenSSL::HMAC`.  Example:

```ruby
"" + nil
# TypeError (no implicit conversion of nil into String)

{}.merge(nil)
# TypeError (no implicit conversion of nil into Hash)

[] + nil
# TypeError (no implicit conversion of nil into Array)
```

Now, we could change all such error messages, by changing internal APIs to pass the method name, argument name, etc..  However, that is a ton of work for a minor benefit, and it doesn't really fit the dynamic nature of Ruby.  The truth is, `nil` is an acceptable value for all of these methods, assuming you define the appropriate methods on it:

```ruby
def nil.to_str; '' end
def nil.to_ary; [] end
def nil.to_hash; {} end

require 'openssl'

OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), nil, 'RubyRuby')
# => "\x06\e\xD0(\x99\xC8\xD9\fQ\xD7\x84\xAAZ\x9D\x9F\xF4\xFF#\x83\x83\x84[\xAD\x87\x7F\xC8\xB6\xF9\xADe\x17!"

"" + nil
# => ""

{}.merge(nil)
# => {}

[] + nil
# => []
```

Once you understand this, you'll probably understand why the error messages are the way they are.

----------------------------------------
Feature #14278: Ambiguous Exception for OpenSSL::HMAC.digest
https://bugs.ruby-lang.org/issues/14278#change-78764

* Author: KINGSABRI (KING SABRI)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
The `OpenSSL::HMAC.digest` shows unclear and ambiguous exception when key is nil.


~~~ ruby
require 'openssl'

key = nil
OpenSSL::HMAC.digest(OpenSSL::Digest.new('sha256'), key, 'RubyRuby')
TypeError: no implicit conversion of nil into String
`digest'
~~~

**Expected Behavior**
So clear and understandable issue, such: 

~~~ text
key argument cannot be nil for OpenSSL::HMAC.digest
~~~








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