[repo-assist] [Repo Assist] Monthly Activity 2026-09

🤖 *Repo Assist here — I'm an automated AI assistant for this repository.*

## Activity for September 2026

## Suggested Actions for Maintainer

- **PR #733** — "Big Deedle updates" by `@Strydrath`: large external contribution (44 files, +7425/-128). Repo Assist reviewed it in detail (build/tests/benchmarks all pass, ~1000x speedup claim verified for indexed filter path). Suggested the maintainer consider whether splitting the PR (CSV/Parquet virtual readers vs. ML export) would ease review. Awaiting maintainer decision.
- **PR #734** — repo-assist testing PR (`windowDist`/`chunkDist`/`pairwiseWith` tests), open since 2026-08-30, no CI runs recorded yet. Needs a maintainer look or a Repo Assist follow-up in a future Task 6 pass.
- **New PR from this run**: "Fix Snappier high-severity vulnerability, update fsdocs-tool" — pins `Snappier >= 1.3.1` (fixes GHSA-pggp-6c3x-2xmx, high severity, transitive via Parquet.Net) and bumps `fsdocs-tool` 22.0.0 → 22.2.0. Build/tests verified (720 + 55 Parquet tests passing). Draft, ready for review.
- **New PR from this run**: "Add Frame.Between/After/Before/StartAt/EndAt row-range slicing" — closes an API symmetry gap versus `Series`. Build/tests verified (722/722 passing). Draft, ready for review.
- **Issue #509** (multi-key/many-to-many joining feature proposal): still open; core single-column join (`Frame.joinOn`) shipped via PR #630, but many-to-many joins and arbitrary key-mapping (`Frame.align`-style) remain unimplemented. No new activity since March 2026 — low priority unless a contributor picks it up.
- **Issue #531** (fslab docs/onboarding): Repo Assist previously assessed the original request as fulfilled and flagged it as closeable (March 2026). No objections since — maintainer may wish to close it.
- **Known dependency risk (not yet fixed)**: `OpenTelemetry.Api` 1.15.1 has a moderate-severity advisory (GHSA-g94r-2vxg-569j), pulled in transitively (likely via BenchmarkDotNet or the test SDK chain). Needs investigation into which top-level package to bump and whether a major version jump is required — deferred to a future Engineering Investments run.

## Future Work

- Investigate and resolve the `OpenTelemetry.Api` moderate-severity advisory.
- Consider whether `Frame.align`-style many-to-many joining (issue #509) is worth implementing in core.
- Revisit PR #734 CI status once it has run at least once.

## Run History

- **2026-09-06** ([run](https://github.com/fslaborg/Deedle/actions/runs/34011380030)): Tasks 4, 5, 7(→2 fallback), 11. Task 4: fixed Snappier high-severity vulnerability (pinned `>= 1.3.1`) and bumped `fsdocs-tool` to 22.2.0; opened draft PR. Task 5: added `Frame.Between/After/Before/StartAt/EndAt` members + module functions with tests (722/722 passing); opened draft PR. Task 7: no non-repo-assist PRs stale 14+ days (PR #733 updated same day, already freshly reviewed) — substituted Task 2, reviewed issues #509 and #531 but both already have recent, still-relevant Repo Assist comments with no new human activity, so no further comment posted. Task 11: closed previous month's issue (#727), opened this new issue for September.

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---

🤖 *Repo Assist here — I'm an automated AI assistant for this repository.*

## Activity for September 2026

## Suggested Actions for Maintainer

* [ ] **Review PR** #733: "Big Deedle updates" by `@Strydrath` — large external contribution (44 files, +7425/-128); build/tests/benchmarks pass, ~1000x speedup verified for indexed filter path; consider splitting (CSV/Parquet virtual readers vs. ML export) — [Review](https://github.com/fslaborg/Deedle/pull/733)
* [ ] **Review PR** #734: repo-assist testing PR (`windowDist`/`chunkDist`/`pairwiseWith` tests), open since 2026-08-30, no CI recorded yet — [Review](https://github.com/fslaborg/Deedle/pull/734)
* [ ] **Review PR** #735: repo-assist PR pinning Snappier + bumping fsdocs-tool — could not be auto-pushed (protected `.config/dotnet-tools.json`); superseded in spirit by the new #aw_secpr below which only touches unprotected files — consider closing #735 in favour of the new PR — [Review](https://github.com/fslaborg/Deedle/pull/735)
* [ ] **Review PR** #736: repo-assist PR adding `Frame.Between/After/Before/StartAt/EndAt` — [Review](https://github.com/fslaborg/Deedle/pull/736)
* [ ] **Review PR**: new draft "Fix Snappier and OpenTelemetry.Api security vulnerabilities" from this run — pins `Snappier >= 1.3.1` (GHSA-pggp-6c3x-2xmx, high) and `OpenTelemetry.Api >= 1.15.3` (GHSA-g94r-2vxg-569j, moderate); build + 928 + 55 tests pass; clean restore confirms both NU1902 warnings are gone — [View open Repo Assist PRs](https://github.com/fslaborg/Deedle/pulls?q=is:pr+is:open+%5Brepo-assist%5D)
* [ ] **Review PR**: new draft "Perf: use O(1) RowCount/ColumnCount instead of Seq.length scans" from this run — removes 3 O(N) `Seq.length` scans in `Frame.AddColumn`/`RenameColumns`/`indexColsWith`; ~14% faster `AddColumn` on a 2M-row benchmark; 928/928 tests pass — [View open Repo Assist PRs](https://github.com/fslaborg/Deedle/pulls?q=is:pr+is:open+%5Brepo-assist%5D)
* [ ] **Check comment** #509: Repo Assist reassessed multi-key joining after `Frame.joinOn` shipped — no new activity since March 2026 — [View](https://github.com/fslaborg/Deedle/issues/509)
* [ ] **Close issue** #531: fslab docs/onboarding — Repo Assist flagged as closeable (original request fulfilled); no objections since March 2026 — [View](https://github.com/fslaborg/Deedle/issues/531)

## Future Work for Repo Assist

- Revisit PR #734 CI status once it has run at least once.
- Consider whether `Frame.align`-style many-to-many joining (issue #509) is worth implementing in core.
- Once maintainers weigh in on #735 vs. the new security PR, close whichever is redundant.

## Run History

### 2026-09-13 04:25 UTC — [Run](https://github.com/fslaborg/Deedle/actions/runs/34737790406)
- 🔧 Created PR: "Fix Snappier and OpenTelemetry.Api security vulnerabilities" — resolves both currently-known NuGet advisories (Snappier high-severity infinite loop, OpenTelemetry.Api moderate excessive-allocation); build + 928 Deedle tests + 55 Parquet tests pass
- 🔧 Created PR: "Perf: use O(1) RowCount/ColumnCount instead of Seq.length scans" — removes O(N) scans in `Frame.AddColumn`/`RenameColumns`/`indexColsWith`; ~14% faster on 2M-row benchmark; 928/928 tests pass
- Investigated Task 2 candidates: issues #509 and #531 both reviewed — no new human activity since last Repo Assist comment on either, so no further comment posted (avoided redundant noise)
- 📝 Updated this Monthly Activity issue with the new checklist format and current PR/issue state

### 2026-09-06 04:50 UTC — [Run](https://github.com/fslaborg/Deedle/actions/runs/34011380030)
- Tasks 4, 5, 7(→2 fallback), 11. Task 4: fixed Snappier high-severity vulnerability (pinned `>= 1.3.1`) and bumped `fsdocs-tool` to 22.2.0; opened draft PR #735 (could not auto-push due to protected `.config/dotnet-tools.json`). Task 5: added `Frame.Between/After/Before/StartAt/EndAt` members + module functions with tests (722/722 passing); opened draft PR #736. Task 7: no non-repo-assist PRs stale 14+ days — substituted Task 2, reviewed issues #509/#531 with no new activity, no comment posted. Task 11: closed previous month's issue (#727), opened this issue.

> Generated by 🌈 Repo Assist, see [workflow run](https://github.com/fslaborg/Deedle/actions/runs/34737790406). [Learn more](https://github.com/githubnext/agentics/blob/main/docs/repo-assist.md).
> _{Comment /repo-assist to run again}> Generated by 🌈 Repo Assist, see [workflow run](https://github.com/fslaborg/Deedle/actions/runs/34737790406). [Learn more](https://github.com/githubnext/agentics/blob/main/docs/repo-assist.md).
> _{Comment /repo-assist to run again}
>

_{Add this agentic workflow to your repo}

To install this agentic workflow, run

```
gh aw add githubnext/agentics/workflows/repo-assist.md@ae8d551f07c7ed7619f8c58c7bb4c3ac89395d38
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This issue is a generated September activity report rather than a standalone change request. Start by reviewing PRs #733–#736 and the referenced issues #509 and #531; completion depends on maintainer review, decisions, or closure rather than a code edit described here.

Written by the indexing model from the issue text.