The following code yields an unexpected exception:
open(\"52bbe674cdc81d4140099b84fa69eea4249bcceee75bcbe4838d911ab076547cfdad3c1c5197752a98e5525fe76613dbe52
I've found a solution. It turns out that I'm not dealing with pure ext4---it's actually ecryptfs layered atop ext4, carried over from a previous Ubuntu install. As suggested in an unaccepted answer to this related question the ecryptfs layer imposes a limit of 143 characters to the filename length. A definitive answer to the file name length limit under ecryptfs can be found here.