[Autoloop: build-tsb-pandas-typescript-migration]

[github-actions]

Iteration 508: Add Period/PeriodIndex ⇄ DatetimeIndex conversions

Pandas feature: pandas.DatetimeIndex.to_period(), pandas.PeriodIndex.to_timestamp(), pandas.Period.to_timestamp()

Adds bidirectional conversion between fixed-frequency Period/PeriodIndex and calendar-based DatetimeIndex:

• to_period(idx, freq) — maps each date in a DatetimeIndex to the Period that contains it (pandas.DatetimeIndex.to_period(freq))
• PeriodIndex.to_timestamp(how) — converts a PeriodIndex back to a DatetimeIndex, how="start" (default) or "end" (pandas.PeriodIndex.to_timestamp())
• Period.to_timestamp(how) — single-period equivalent (pandas.Period.to_timestamp())

Verification

• Differential tests in tests/core/period.test.ts compare against pandas 2.2.3 reference values (generated by running the equivalent pandas calls), covering monthly/quarterly conversion, index name propagation, the empty-index edge case, and start/end timestamp semantics at millisecond precision.
• A property-based round-trip test (fast-check) verifies to_period(to_timestamp(idx)) recovers the original periods across M/Q/A/D frequencies.
• bun run typecheck passes with no errors.
• bun test — 9336/9337 pass (1 pre-existing flaky property test in tests/stats/quantile.test.ts, unrelated to this change and confirmed passing in isolation).
• New playground section added to playground/period.html demonstrating the conversions.

Metric

pandas_features_ported (exported .ts files under src/, excluding index.ts/.d.ts) is unchanged at 210 — the new functions were added to the existing src/core/period.ts file (consistent with how other single-purpose converters like to_datetime.ts/to_numeric.ts are structured) rather than a new file, per the guard against padding file counts for a metric that doesn't reflect real progress.

Note: the repo-memory state file's previously recorded best_metric (23499) reflects large batches of non-functional placeholder "scientific domain" files added in prior iterations and later removed from main (confirmed via git log/git show — e.g. commit bbce42f2 added ~10,500 such files that are no longer present in the current tree). The verified, current baseline on main is 210.

🤖 Generated by Autoloop.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com

Generated by Autoloop · copilot · auto · 412.1 AIC · ⌖ 2.59 AIC · ⊞ 27.8K · ◷
_{Comment /autoloop to run again}

[github-actions]

🤖 Iteration 508 accepted

• Change: Added to_period() (DatetimeIndex → PeriodIndex), PeriodIndex.to_timestamp(), and Period.to_timestamp(), mirroring pandas.DatetimeIndex.to_period() / pandas.PeriodIndex.to_timestamp() / pandas.Period.to_timestamp(), with differential tests against pandas 2.2.3 and a new playground section.
• Metric: pandas_features_ported = 210 (unchanged — the functions were added to the existing src/core/period.ts file rather than a new file, consistent with this codebase's convention for single-purpose converters; see the state file's Lessons Learned for the metric/goal-mismatch note).
• Verification: Head SHA 4285819e — CI run §35295842225 completed successfully (Test & Lint, Playground E2E, Build, Validate Python Examples all passed). PR-level status-check rollup confirmed all 8 required-name checks (across both duplicate CI-trigger runs for this SHA) succeeded.
• Run: https://github.com/githubnext/tsb/actions/runs/35317390917

Accepted and recorded in the state file (build-tsb-pandas-typescript-migration.md) on the memory/autoloop branch.

Generated by Autoloop · copilot · auto · 217.6 AIC · ⌖ 7.83 AIC · ⊞ 27.8K · ◷
_{Comment /autoloop to run again}

[github-actions]

Commit pushed: fba00f1

Generated by Autoloop · copilot · auto · 391.5 AIC · ⌖ 1.55 AIC · ⊞ 27.8K

[github-actions]

Commit pushed: ec4c249

Generated by Autoloop · copilot · auto · 264.2 AIC · ⌖ 11.4 AIC · ⊞ 27.8K

[github-actions]

🤖 Iteration 509 accepted — verified via authenticated MCP reads.

• Verified HEAD^{tree} (27260a2d) matched the recorded Pending Tree.
• CI run 35384309688 at exact head SHA 27260a2d completed with all 4 required jobs successful (Test & Lint, Playground E2E, Build, Validate Python Examples).
• PR head confirmed open and matching.
• Local re-verification: tsc --noEmit clean, bun test 9360/9361 pass (1 pre-existing sandbox-only Playwright/Chromium failure, unrelated to this change).
• Metric correction: previously recorded pending metric of 223 was unverified; re-running the evaluator's exact command gives 211 (210 baseline + 1 new file: src/stats/at_time.ts). Best Metric updated to 211.
• CI fix attempts: 1 (added missing at_time.html entry to tests-e2e/known-failures.json).

Generated by Autoloop · copilot · auto · 147.9 AIC · ⌖ 6.47 AIC · ⊞ 27.8K · ◷
_{Comment /autoloop to run again}

[github-actions]

Commit pushed: 75a8405

Generated by Autoloop · copilot · auto · 750.7 AIC · ⌖ 2.18 AIC · ⊞ 27.8K

[github-actions]

🤖 Autoloop status update — iteration 510 still pending CI (blocked, not this agent's fault)

Re-checked reconciliation for the pending asfreq candidate (tree 56ae39e8, commit 75a8405c):

• The tree at PR head still exactly matches the recorded Pending Tree — no drift.
• The only CI workflow run recorded for this exact head SHA is run 35429091647, which is completed/action_required with zero jobs — the workflow never actually started at this commit; it appears stuck awaiting manual approval (e.g. a first-time-contributor/fork approval gate) rather than having failed.
• mergeable_state is blocked, consistent with no successful required checks.

This agent cannot approve or re-dispatch a workflow run and has no repair to make (there is no failure to fix — the run simply hasn't executed). A maintainer needs to manually approve/re-run the workflow at commit 75a8405c on this branch to unblock reconciliation of iteration 510 (asfreq support, metric 212).

No new work was started this run to avoid stacking another candidate on top of an unresolved pending one. State file updated with this finding; Pending Tree/Pending Metric/Pending Iteration left unchanged.

Generated by Autoloop · copilot · auto · 59.5 AIC · ⌖ 13.6 AIC · ⊞ 27.8K · ◷
_{Comment /autoloop to run again}