v4.3.0-rc2

What's Changed

• feat: reorder Lake help by @semorrison in #2725
• fix: lake: consistent order for manifest packages by @tydeu in #2788
• chore: fix duplication in release notes by @semorrison in #2794
• chore: change simp default to decide := false by @collares in #2722
• doc: Add docstrings to dbg_trace and assert! in do blocks by @nomeata in #2787
• feat: hovers on open and export decls by @digama0 in #2797
• Teach CMake about LLVM builds by @hargoniX in #2809
• fix: fixes #2775 by @leodemoura in #2790
• perf: avoid quadratic number of info tree nodes in DecEq deriving handler by @Kha in #2820
• feat: Better error location in structural recursion by @nomeata in #2819
• fix: Escape ? in C literal strings to avoid trigraphs by @nomeata in #2833
• test: C trigraph by @nomeata in #2832
• doc: mention the proof-binding syntax in match by @eric-wieser in #2834
• Ensure nested proofs in equation and unfold lemmas have been abstracted by @leodemoura in #2825
• chore: add import Lean benchmark by @Kha in #2840
• feat: extend API of KVMap by @semorrison in #2851
• feat: Lean.Linter.logLintIf by @semorrison in #2852
• fix: issue 2042 by @leodemoura in #2783
• doc: fix typo by @marcusrossel in #2856
• refactor: TerminationHint: Remove duplicted code line by @nomeata in #2859
• feat: find Decidable instances via unification by @semorrison in #2816
• feat: add left/right actions to term tree coercion elaborator and make ^ a right action by @kmill in #2778
• refactor: .lake directory for Lake outputs by @tydeu in #2749
• Mark environments not freed before process exit persistent eagerly by @Kha in #2841
• fix: re-read HTTP header when skipping notification in Ipc.readResponseAs by @Kha in #2870
• fix: have parenthesizer copy source info to parenthesized term by @kmill in #2866
• doc: fix typo by @eric-wieser in #2878
• refactor: lake: more flexible manifest by @tydeu in #2801
• feat: release web assembly by @abentkamp in #2855
• doc: code owners by @Kha in #2875
• fix: stricter lakefile.olean compatibility check by @tydeu in #2842

Full Changelog: v4.3.0-rc1...v4.3.0-rc2

v4.3.0-rc1

• Many bug fixes:
  • Reduction of Decidable instances very slow when using cases tactic
  • simp not rewriting in binder
  • simp unfolding let even with zeta := false option
  • simp (with beta/zeta disabled) and discrimination trees
  • unknown free variable introduced by rw ... at h
  • dsimp doesn't use rfl theorems which consist of an unapplied constant
  • dsimp does not close reflexive equality goals if they are wrapped in metadata
  • rw [h] uses h from the environment in preference to h from the local context
  • missing withAssignableSyntheticOpaque for assumption tactic
  • ignoring default value for field warning
• Cancel outstanding tasks on document edit in the language server.
• Remove unnecessary % operations in Fin.mod and Fin.div
• Avoid DecidableEq in Array.mem
• Ensure USize.size unifies with ?m + 1
• Improve compatibility with emacs eglot client

Lake:

• Sensible defaults for lake new MyProject math
• Changed postUpdate? configuration option to a post_update declaration. See the post_update syntax docstring for more information on the new syntax.
• A manifest is automatically created on workspace load if one does not exists..
• The := syntax for configuration declarations (i.e., package, lean_lib, and lean_exe) has been deprecated. For example, package foo := {...} is deprecated.
• support for overriding package URLs via LAKE_PKG_URL_MAP

v4.2.0

v4.2.0

• isDefEq cache for terms not containing metavariables..
• Make Environment.mk and Environment.add private, and add replay as a safer alternative.
• IO.Process.output no longer inherits the standard input of the caller.
• Do not inhibit caching of default-level match reduction.
• List the valid case tags when the user writes an invalid one.
• The derive handler for DecidableEq now handles mutual inductive types.
• Show path of failed import in Lake.
• Fix linker warnings on macOS.
• Lake: Add postUpdate? package configuration option. Used by a package to specify some code which should be run after a successful lake update of the package or one of its downstream dependencies. (lake#185)
• Improvements to Lake startup time (#2572, #2573)
• refine e now replaces the main goal with metavariables which were created during elaboration of e and no longer captures pre-existing metavariables that occur in e (#2502).
  • This is accomplished via changes to withCollectingNewGoalsFrom, which also affects elabTermWithHoles, refine', calc (tactic), and specialize. Likewise, all of these now only include newly-created metavariables in their output.
  • Previously, both newly-created and pre-existing metavariables occurring in e were returned inconsistently in different edge cases, causing duplicated goals in the infoview (issue #2495), erroneously closed goals (issue #2434), and unintuitive behavior due to refine e capturing previously-created goals appearing unexpectedly in e (no issue; see PR).

Merged PRs

• Add new issue templates by @mhuisi in #2519
• chore: begin development cycle for 4.2.0 by @semorrison in #2545
• chore: do not generate PR releases from forks by @semorrison in #2550
• chore: when bumping Mathlib testing branches, bump to latest nightly-testing by @semorrison in #2553
• fix: uninterpolated error message in registerRpcProcedure by @thorimur in #2547
• Enforce linebreak between calc steps by @Kha in #2532
• fix: rename parameter of withImportModules to match doc string by @dwrensha in #2530
• perf: reduce allocations in unused variable linter by @hargoniX in #2491
• fix: set MACOSX_DEPLOYMENT_TARGET in CI only by @Kha in #2556
• CI: label stale PRs by @Kha in #2561
• chore: disambiguate whnf system category by @Kha in #2560
• fix: use MoveFileEx for rename on win by @digama0 in #2546
• fix: set ref in getCalcFirstStep by @PatrickMassot in #2563
• perf: Use flat ByteArrays in Trie by @nomeata in #2529
• chore: update domain by @Kha in #2566
• feat: lake: add name to manifest by @tydeu in #2565
• fix: only return new mvars from refine, elabTermWithHoles, and withCollectingNewGoalsFrom by @thorimur in #2502
• fix: don't try to generate below for nested predicates. by @arthur-adjedj in #2390
• perf: do not detect lean's toolchain by @tydeu in #2570
• test: add lake benchmarks by @tydeu in #2457
• perf: lake: build lakefile environments incrementally by @Kha in #2573
• perf: lake: no lean --githash when collocated by @tydeu in #2572
• test: lake: add env & dep cfg benchmarks + cleanup by @tydeu in #2574
• perf: lake: lazily acquire repo URL/tag in :release by @tydeu in #2583
• doc: add token error change to RELEASES.md by @Kha in #2579
• chore: begin development cycle for v4.3.0 by @semorrison in #2585
• fix: hover term/tactic confusion by @digama0 in #2586
• doc: fix doc comment syntax in declModifiers doc comment by @nomeata in #2590
• chore: add release note about lake startup time by @semorrison in #2597
• chore: Remove unused variables from kernel by @nomeata in #2576
• Fix typos by @DenisGorbachev in #2605
• docs: update RELEASES.md for #2502 by @thorimur in #2606
• [Backport releases/v4.2.0] docs: update RELEASES.md for #2502 by @github-actions in #2613
• refactor: remove redundant let by @DenisGorbachev in #2614
• Fix linker warnings on macOS by @Kha in #2598
• feat : derive DecidableEq for mutual inductives by @arthur-adjedj in #2591
• fix: withLocation should use withMainContext for target by @alexjbest in #2607
• fix: XML parsing bugs by @kuruczgy in #2601
• feat: Web Assembly Build by @abentkamp in #2599
• feat: make Environment.mk private by @digama0 in #2604
• doc: fix the link to contribution guidelines by @DenisGorbachev in #2623
• feat: show path of failed import by @bollu in #2616
• doc: add missing character in testing.md by @david-christiansen in #2630
• Tag names by @david-christiansen in #2629
• fix: eliminate widestring uses by @Kha in #2633
• chore: fix typos in comments by @int-y1 in #2636
• chore: fix more typos in comments by @int-y1 in #2638
• perf: do not inhibit caching of default-level match reduction by @Kha in #2612
• chore: add missing if statements to pr-release.yml workflow by @semorrison in #2639
• chore: fix MVarId.getType' by @semorrison in #2595
• chore: add axiom for tracing use of reduceBool / reduceNat by @semorrison in #2654
• feat: replay constants into an Environment by @semorrison in #2617
• chore: remove unnecessary partial in ForEachExpr.visit by @digama0 in #2657
• chore: change trustCompiler axiom to True by @semorrison in #2662
• Add development process docs by @david-christiansen in #2650
• fix: treat pretty-printed names as strings by @Vtec234 in #2652
• feat: ToMessageData (α × β) instance by @digama0 in #2658
• fix: implementation of Array.anyMUnsafe by @semorrison in #2641
• perf: use quick_is_def_eq first by @digama0 in #2671
• chore: make Environment.add private by @semorrison in #2642
• fix: quot reduction bug by @digama0 in #2673
• fix: stdin := .null in IO.Process.output by @tydeu in #2544
• test: lake: show module with failed import by @tydeu in #2677
• feat: lake: postUpdate? + test by @tydeu in #2603
• Cancel outstanding tasks on document edit in the language server by @Kha in #2648
• feat: lake: --no-build option to exit before a build by @tydeu in #2651
• Machinery for opt-in builds in language server by @Kha in #2665
• fix : make mk_no_confusion_type handle delta-reduction when generating telescope by @arthur-adjedj in #2501
• isDefEq cache for terms not containing metavariables. by @leodemoura in #2644
• chore: simp tracing reports ← by @semorrison in #2621
• feat: use nat_gcd in the kernel by @semorrison in #2533
• chore: add items to RE...

v4.2.0-rc4

Full Changelog: v4.2.0-rc3...v4.2.0-rc4

Fixes a bug that could lead to data loss from lake clean when switching between this version and previous stable versions. Users upgrading a project from 4.2.0-rc2 or 4.2.0-rc3 should manually remove their lakefile.olean after adjusting lean-toolchain.

v4.2.0-rc3

This version is known to contain a bug that could lead to data loss from lake clean, which has been fixed in 4.2.0-rc4. Users upgrading a project from this version to 4.2.0 rc4 should manually remove their lakefile.olean after adjusting lean-toolchain.

This is a fix for v4.2.0-rc2 as lean4#2648 appears to cause intermittent crashes in VSCode.

v4.2.0-rc2

This version is known to contain a bug that could lead to data loss from lake clean, which has been fixed in 4.2.0-rc4. Users upgrading a project from this version to 4.2.0 rc4 should manually remove their lakefile.olean after adjusting lean-toolchain.

What's Changed

• perf: lake: lazily acquire repo URL/tag in :release by @tydeu in #2583
• doc: add token error change to RELEASES.md by @Kha in #2579
• chore: begin development cycle for v4.3.0 by @semorrison in #2585
• fix: hover term/tactic confusion by @digama0 in #2586
• doc: fix doc comment syntax in declModifiers doc comment by @nomeata in #2590
• chore: add release note about lake startup time by @semorrison in #2597
• chore: Remove unused variables from kernel by @nomeata in #2576
• Fix typos by @DenisGorbachev in #2605
• docs: update RELEASES.md for #2502 by @thorimur in #2606
• [Backport releases/v4.2.0] docs: update RELEASES.md for #2502 by @github-actions in #2613
• refactor: remove redundant let by @DenisGorbachev in #2614
• Fix linker warnings on macOS by @Kha in #2598
• feat : derive DecidableEq for mutual inductives by @arthur-adjedj in #2591
• fix: withLocation should use withMainContext for target by @alexjbest in #2607
• fix: XML parsing bugs by @kuruczgy in #2601
• feat: Web Assembly Build by @abentkamp in #2599
• feat: make Environment.mk private by @digama0 in #2604
• doc: fix the link to contribution guidelines by @DenisGorbachev in #2623
• feat: show path of failed import by @bollu in #2616
• doc: add missing character in testing.md by @david-christiansen in #2630
• Tag names by @david-christiansen in #2629
• fix: eliminate widestring uses by @Kha in #2633
• chore: fix typos in comments by @int-y1 in #2636
• chore: fix more typos in comments by @int-y1 in #2638
• perf: do not inhibit caching of default-level match reduction by @Kha in #2612
• chore: add missing if statements to pr-release.yml workflow by @semorrison in #2639
• chore: fix MVarId.getType' by @semorrison in #2595
• chore: add axiom for tracing use of reduceBool / reduceNat by @semorrison in #2654
• feat: replay constants into an Environment by @semorrison in #2617
• chore: remove unnecessary partial in ForEachExpr.visit by @digama0 in #2657
• chore: change trustCompiler axiom to True by @semorrison in #2662
• Add development process docs by @david-christiansen in #2650
• fix: treat pretty-printed names as strings by @Vtec234 in #2652
• feat: ToMessageData (α × β) instance by @digama0 in #2658
• fix: implementation of Array.anyMUnsafe by @semorrison in #2641
• perf: use quick_is_def_eq first by @digama0 in #2671
• chore: make Environment.add private by @semorrison in #2642
• fix: quot reduction bug by @digama0 in #2673
• fix: stdin := .null in IO.Process.output by @tydeu in #2544
• test: lake: show module with failed import by @tydeu in #2677
• feat: lake: postUpdate? + test by @tydeu in #2603
• Cancel outstanding tasks on document edit in the language server by @Kha in #2648
• feat: lake: --no-build option to exit before a build by @tydeu in #2651
• Machinery for opt-in builds in language server by @Kha in #2665
• fix : make mk_no_confusion_type handle delta-reduction when generating telescope by @arthur-adjedj in #2501
• isDefEq cache for terms not containing metavariables. by @leodemoura in #2644
• chore: simp tracing reports ← by @semorrison in #2621
• feat: use nat_gcd in the kernel by @semorrison in #2533
• chore: add items to RELEASES.md by @semorrison in #2687

New Contributors

• @DenisGorbachev made their first contribution in #2605
• @kuruczgy made their first contribution in #2601
• @abentkamp made their first contribution in #2599

Full Changelog: v4.2.0-rc1...v4.2.0-rc2

v4.2.0-rc1

No breaking changes so far since v4.1.0.

What's Changed

• Add new issue templates by @mhuisi in #2519
• chore: begin development cycle for 4.2.0 by @semorrison in #2545
• chore: do not generate PR releases from forks by @semorrison in #2550
• chore: when bumping Mathlib testing branches, bump to latest nightly-testing by @semorrison in #2553
• fix: uninterpolated error message in registerRpcProcedure by @thorimur in #2547
• Enforce linebreak between calc steps by @Kha in #2532
• fix: rename parameter of withImportModules to match doc string by @dwrensha in #2530
• perf: reduce allocations in unused variable linter by @hargoniX in #2491
• fix: set MACOSX_DEPLOYMENT_TARGET in CI only by @Kha in #2556
• CI: label stale PRs by @Kha in #2561
• chore: disambiguate whnf system category by @Kha in #2560
• fix: use MoveFileEx for rename on win by @digama0 in #2546
• fix: set ref in getCalcFirstStep by @PatrickMassot in #2563
• perf: Use flat ByteArrays in Trie by @nomeata in #2529
• chore: update domain by @Kha in #2566
• feat: lake: add name to manifest by @tydeu in #2565
• fix: only return new mvars from refine, elabTermWithHoles, and withCollectingNewGoalsFrom by @thorimur in #2502
• fix: don't try to generate below for nested predicates. by @arthur-adjedj in #2390
• perf: do not detect lean's toolchain by @tydeu in #2570
• test: add lake benchmarks by @tydeu in #2457
• perf: lake: build lakefile environments incrementally by @Kha in #2573
• perf: lake: no lean --githash when collocated by @tydeu in #2572
• test: lake: add env & dep cfg benchmarks + cleanup by @tydeu in #2574

Full Changelog: v4.1.0...v4.2.0-rc1

v4.1.0

Significant changes since v4.0.0

• The error positioning on missing tokens has been improved. In particular, this should make it easier to spot errors in incomplete tactic proofs.

• After elaborating a configuration file, Lake will now cache the configuration to a lakefile.olean. Subsequent runs of Lake will import this OLean instead of elaborating the configuration file. This provides a significant performance improvement (benchmarks indicate that using the OLean cuts Lake's startup time in half), but there are some important details to keep in mind:

  • Lake will regenerate this OLean after each modification to the lakefile.lean or lean-toolchain. You can also force a reconfigure by passing the new --reconfigure / -R option to lake.
  • Lake configuration options (i.e., -K) will be fixed at the moment of elaboration. Setting these options when lake is using the cached configuration will have no effect. To change options, run lake with -R / --reconfigure.
  • The lakefile.olean is a local configuration and should not be committed to Git. Therefore, existing Lake packages need to add it to their .gitignore.

• The signature of Lake.buildO has changed, args has been split into weakArgs and traceArgs. traceArgs are included in the input trace and weakArgs are not. See Lake's FFI example for a demonstration of how to adapt to this change.

• The signatures of Lean.importModules, Lean.Elab.headerToImports, and Lean.Elab.parseImports
  have changed from taking List Import to Array Import.

• There is now an occs field
  in the configuration object for the rewrite tactic,
  allowing control of which occurrences of a pattern should be rewritten.
  This was previously a separate argument for Lean.MVarId.rewrite,
  and this has been removed in favour of an additional field of Rewrite.Config.
  It was not previously accessible from user tactics.

Contributors

% git log v4.0.0..v4.1.0 --pretty="%an" | sort | uniq -c | sort -rn
  28 Mac Malone
   9 Scott Morrison
   8 Sebastian Ullrich
   2 Mario Carneiro
   2 Jannis Limperg
   1 mhuisi
   1 github-actions[bot]
   1 Marcus Rossel
   1 Joachim Breitner

v4.1.0-rc1

This is the first release candidate for v4.1.0-rc1. We are switching to using a tracking branch for this release, at release/v4.1.0. We hope to cherry-pick any critical fixes onto this branch, rather than moving up to master for any subsequent release candidates.

Breaking changes since v4.0.0:

• After elaborating a configuration file, Lake will now cache the configuration to a lakefile.olean. Subsequent runs of Lake will import this OLean instead of elaborating the configuration file. This provides a significant performance improvement (benchmarks indicate that using the OLean cuts Lake's startup time in half), but there are some important details to keep in mind:

  • Lake will regenerate this OLean after each modification to the lakefile.lean or lean-toolchain. You can also force a reconfigure by passing the new --reconfigure / -R option to lake.
  • Lake configuration options (i.e., -K) will be fixed at the moment of elaboration. Setting these options when lake is using the cached configuration will have no effect. To change options, run lake with -R / --reconfigure.
  • The lakefile.olean is a local configuration and should not be committed to Git. Therefore, existing Lake packages need to add it to their .gitignore.

• The signature of Lake.buildO has changed, args has been split into weakArgs and traceArgs. traceArgs are included in the input trace and weakArgs are not. See Lake's FFI example for a demonstration of how to adapt to this change.

• The signatures of Lean.importModules, Lean.Elab.headerToImports, and Lean.Elab.parseImports have changed from taking List Import to Array Import.

• There is now an occs field in the configuration object for the rewrite tactic, allowing control of which occurrences of a pattern should be rewritten. This was previously a separate argument for Lean.MVarId.rewrite, and this has been removed in favour of an additional field of Rewrite.Config. It was not previously accessible from user tactics.

v4.0.0

This is the first official release of Lean 4.

We intend to begin regular releases of Lean 4, providing a new "minor" version approximately monthly.
We do not yet make promises about backwards compatibility, although all breaking changes will be documented in RELEASES.md.

Please visit

• Our community forum on Zulip! This is the best place to get help, and find out what the Lean community is working on.
• The Lean language website for downloads and documentation.
• The homepage of the Lean Focused Research Organization for the team behind Lean.
• The Lean community website for help getting started, tutorials, and information about Mathlib.
• The Mathlib GitHub repository, for Lean's major mathematical library.

We have had over 2000 commits since the previous milestone.

% git log v4.0.0-m5..v4.0.0 --pretty="%an" | sort | uniq -c | sort -rn
 833 Leonardo de Moura
 662 Mac Malone
 301 Sebastian Ullrich
 228 Gabriel Ebner
 215 Mario Carneiro
  46 Henrik Böving
  41 Ed Ayers
  26 Scott Morrison
  20 Siddharth Bhat
  12 Wojciech Nawrocki
  11 Bulhwi Cha
   8 Adrien Champion
   7 Chris Lovett
   6 Alex J Best
   5 Yuri de Wit
   5 Tobias Grosser
   4 Rishikesh Vaishnav
   4 David Renshaw
   3 pcpthm
   3 int-y1
   3 Patrick Massot
   3 Martin Dvořák
   3 Marcus Rossel
   3 Elias Aebi
   2 Pietro Monticone
   2 Parth Shastri
   2 Joachim Breitner
   2 Jannis Limperg
   2 James Gallicchio
   2 François G. Dorais
   2 Floris van Doorn
   2 Eric Wieser
   2 Connor Baker
   2 Chris Hughes
   2 Anders Christiansen Sørby
   1 thorimur
   1 mcdoll
   1 locriacyber
   1 joao guilherme
   1 bc²
   1 awson
   1 ammkrn
   1 Richard Musiol
   1 Olivier Taïbi
   1 Matthias Hetzenberger
   1 Kaiyu Yang
   1 Junyan Xu
   1 Juan Pablo Romero
   1 Jon Eugster
   1 Jeremy Salwen
   1 Jakob von Raumer
   1 Gabriel Dahia
   1 Fynn Schmitt-Ulms
   1 Evgenia Karunus
   1 Enrico Borba
   1 Denis Gorbachev
   1 David Thrane Christiansen
   1 Arthur Paulino
   1 Andrés Goens