No! Android P is not coming with native call recording functionality
Google I/O 2018 is happening in May and just like last year, we are sure that the next version of Android will be announced at the event. It is speculated that the first developer preview of Android P (Android 9.0) is already in works. There are some reports that say the DP1 will be out earlier than last year. Recently, it was reported that as per some latest commits in the Android Open Source Project (AOSP), Google is going to add native call recording in Android 9.0 but looks like that is not going to happen.
The commits do not show evidence of Android P implementing native call recording or an API for third-party call recording.
I have been following these commits since before they were merged, and the gist of why this is inaccurate is because the mention of recording apps is just so Telecom can warn that a call may be recorded. It does this by playing an outgoing 1400Hz tone every 15 seconds while a call is being recorded.
The specific carrier that asked for this is Vodafone in Germany, which you can verify by looking up the MCC/MNC combination mentioned in the file name of one of the comments.
Again, Mishaal mentioned that the latest commits don’t mention any such feature, but there might be chances that Google will add this feature in the next version of Android. We cannot say anything at the moment since we have no details. Stay Tuned as we will be updating you as soon as we get more information on Android P.