[wali-reheman]

www.prisoners-dilemma.com has new ownership and no longer hosts IPD strategy content, so both links now point at Wayback Machine archives.

Per @Evreu1pro's note, the HARD_TFT link is pinned to 20161206214130 — a real capture with the same content digest as every strategies.html capture from 2014 to 2019 — so it no longer depends on a Wayback redirect. The [PD2017] entry keeps 20171227021632, which is a genuine capture of competition.html.

AI tools were used to query the Wayback CDX index and pick the timestamp; the change itself is two link edits.

[drvinceknight]

The failure isn't due to your contribution but to an upstream change in numpy:

  E       - Joss-Ann Tit For Tat: (np.float64(0.0), np.float64(0.0))
  E       + Joss-Ann Tit For Tat: (0.0, 0.0)

[Evreu1pro]

Checked both archive links since CI is green now:

• competition.html at 20171227021632 is a real capture, fine as is.
• strategies.html has no capture at that timestamp, so Wayback silently redirects to the nearest one, 20180130161901. That page does have the definition the docs quote ("Hard Tit for Tat (HTFT): Cooperates on the first move, and defects if the opponent has defects on any of the previous three moves, else cooperates."), so the link works today. It just means the URL in the docs isn't the snapshot you actually land on.

Small nit, not a blocker: pinning the HARD_TFT link to an existing capture, e.g. https://web.archive.org/web/20180130161901/http://www.prisoners-dilemma.com/strategies.html, avoids depending on the redirect. According to the CDX index every capture of strategies.html from 2014 to 2019 has the same content digest, so any of them would do. The 2016-12-06 one (20161206214130) is the closest before the 2017 access date, if you want it to match the bibliography.

[wali-reheman]

good catch — you were right that 20171227021632 has no strategies.html capture. Pinned the HARD_TFT link to 20161206214130, and confirmed via the CDX index that it shares a content digest with every other 2014-2019 capture of that page. [PD2017] keeps 20171227021632 since that one is a real capture of competition.html.