Looks like people forgot about 4 factor of stream enterer. Only a stream enterer and above can recollect their virtues to enter samma samadhi.
SN 55 wrote:...Furthermore, a noble disciple’s ethical conduct is loved by the noble ones, unbroken, impeccable, spotless, and unmarred, liberating, praised by sensible people, not mistaken, and leading to samadhi.
MN 4 described how he used his perfected sila, senses restraint, & others to enter into samma samadhi (aka unification of mind). Only removing the nivaranas then he can enter the samma samadhi.
MN 4 wrote: ... On such nights, why don’t I stay in awe-inspiring and hair-raising shrines in parks, forests, and trees? In such lodgings, hopefully I might see that fear and dread.’ Some time later, that’s what I did. ...
Then that fear and dread came upon me as I was lying down. I didn’t sit up or stand still or walk until I had got rid of that fear and dread while lying down.
...
My energy was roused up and unflagging, my mindfulness was established and lucid, my body was tranquil and undisturbed, and my mind was immersed in samādhi.
Quite secluded from sensual pleasures, secluded from unskillful qualities, I entered and remained in the first jhana....
How can he entered the stream? May I represent you his old friend Ghatikara that reminded him about his past & Buddha Kassapa. You can also see MN 81 and the parallel.
SN 2.24 wrote:“That’s exactly how it was,
just as you say, Bhaggava.
In the past, you were a potter
in Vebhaliṅga called Ghaṭīkāra.
You took care of your parents
as a lay follower of Buddha Kassapa.
You refrained from sexual intercourse,
you were celibate, spiritual.
We lived in the same village;
in the past you were my friend.”
“That’s how it was
when those friends of old met again.
Both of them are evolved,
and bear their final body. (arahanthood)”
Don't worry someone will come up with Commentary to reject it as well. (hint: Third Council).... But, it is only commentary again. Not based on Sutta.