Is an unsuccessful attack on a creature under the effect of Charm Person “harmful” for purposes of ending the spell?

Consider the following elaborate scenario, which nevertheless actually occurred at our table.

Two PCs, Sophie Sorcerer and Roger Rogue, sneak into the hideout of hapless villain Tarley Target. While hidden, Sophie uses her Subtle Casting metamagic to silently cast sleep, rendering Tarley unconscious without ever alerting him to the intrusion. Sophie and Roger swiftly exfiltrate the sleeping Tarley from the hideout to their camp nearby, where Sophie successfully casts charm person on him. When the sleep spell ends and Tarley awakes, Sophie takes advantage of Tarley’s charmed condition: she dupes him into believing that someone else actually assaulted him, and that the PCs are in fact his saviors. Tarley, overcome with gratitude and having little cause to believe the PCs are really hostile, proceeds to spill his secrets. Once satisfied that she has squeezed every bit of useful information from Tarley, Sophie signals to Roger — who has been quietly, nonchalantly moving into striking position — to kill him. Initiative is rolled. Tarley is ruled surprised. Roger goes first, attacks, and misses.

Does Tarley’s charmed condition end?

The description of charm person says a target that fails its save "is charmed by you until the spell ends or until you or your companions do anything harmful to it." Does an unsuccessful attack count as "harmful" for purposes of charm person? Would it make a difference if Tarley remained unaware of the attack — e.g., because (as happened here) the DM ruled him distracted by Sophie’s riveting conversation?

Related questions:

  • This question asked what "harmful" means vis-à-vis charm person, but only in the context that the charmed condition restricts the charmed creature’s ability to "target the charmer with harmful abilities or magical effects."
  • This question asked whether the target of charm person has to know who damaged them in order for the spell to end, but that presumes damage was actually dealt.