John Gill Commentary Judges 1:29

"And Ephraim drove not out the Canaanites that dwelt in Gezer; but the Canaanites dwelt in Gezer among them." — Judges 1:29 (ASV)

Neither did Ephraim drive out the Canaanites that dwelt in
Gezer
Not so much as made them tributaries, but made a covenant with them, it is probable, contrary to the express will of God:

but the Canaanites dwelt in Gezer among them ;
the Ephraimites agreeing to it, and here they dwelt to the times of Solomon; (See Gill on Joshua 16:10); where indeed they are said to be under tribute; but that seems to respect some later time, and not when they were first admitted to dwell among them, since no mention is made of it here.