Who contributed to Elixir & Phoenix on July 18, 2026?

4 developers shipped this update, including José Valim, Alexander Gubarev, preciz, and SteffenDE.

What were the notable Elixir & Phoenix updates?

Optimize equal-head BDD intersections, Avoid cloning keyed comprehensions without moves, and Avoid cloning keyed comprehensions without moves (#4328).

Jul 18, 2026

$ the-wire · showcase

ELIXIR CUTS EXPONENTIAL GROWTH IN BDD INTERSECTIONS, PHOENIX LIVE VIEW SKIPS CLONES ON STABLE LISTS

By RepoJournal · Filed 07:01 UTC on July 18, 2026 · About Elixir & Phoenix · Composed from the cited sources · methodology

4 people shipped this

José Valim @josevalim 2 cited

preciz @preciz 2 cited

Alexander Gubarev @AlexGx 1 cited

SteffenDE @SteffenDE

The compiler just got smarter about preventing exponential blowup in type intersection logic, while Phoenix Live View stops wastefully copying keyed comprehensions that aren't moving.

In brief

Elixir optimized equal-head BDD intersections. exponential slowdown on certain set operations is now gone. if you've ever wondered why a particular lookup felt glacial, this might've been it.
Phoenix Live View now skips cloning keyed comprehensions when there are no moves. less memory churn on stable lists. small change, real impact on render-heavy pages.
IEx.Helpers.process_info/1 heap and stack calculations were wrong. fixed. if you've been debugging memory leaks in prod, your introspection tool just got more honest.

Elixir's BDD intersection optimizer [1] now preserves shared unions only when absorption removes all residual terms, normalizing other equal-head intersections eagerly to prevent the exponential growth that was crushing compile times on complex types. This is a quiet but significant win for anyone working with heavy union logic. On the Phoenix side, Live View [2] [3] clones keyed state only when a diff actually moves entries now, letting stable-position updates merge in place instead of copying the entire cached render tree. The payoff is real: you skip the clone operation entirely when list items stay put, which matters in high-frequency list updates. Meanwhile, IEx got two fixes to stop reporting garbage memory numbers in process_info [4] and to handle module reloads correctly when multiple modules live in the same file . The :pid info assertion removal [5] cleans up test noise upstream.

Action items

→ Merge the BDD intersection fix into your build pipeline if you maintain type-heavy libraries elixir-lang/elixir [plan]
→ Pull the Phoenix Live View keyed comprehension optimization before your next release phoenixframework/phoenix_live_view [plan]
→ Update IEx if you've been troubleshooting memory with process_info elixir-lang/elixir [monitor]

References

[1] Optimize equal-head BDD intersections ↗ elixir-lang/elixir
[2] Avoid cloning keyed comprehensions without moves ↗ phoenixframework/phoenix_live_view
[3] Avoid cloning keyed comprehensions without moves (#4328) ↗ phoenixframework/phoenix_live_view
[4] Fix IEx.Helpers.process_info/1 heap and stack memory calculation (#15628) ↗ elixir-lang/elixir
[5] Remove :pid from info assertions ↗ elixir-lang/elixir