Sprig v0.4.0-alpha.1

Sprig v0.4.0-alpha.1 — formatter, re-exports, match expressions and a correctness pass

Compiler 0.4.0-alpha.1, JDK 17+, Apache-2.0. Experimental Alpha for
trying small tools and contributing, not production migration. Publication runs
through the exact-tag release workflow; the executed evidence is recorded in the
release validation record.

Highlights since v0.3.0-alpha.1

• Canonical formatter — sprig fmt preserves comments and trivia, formats a
  file or a project, supports --check, and replaces files atomically. The
  grammar now retains comments for the formatter while semantic layout stays
  strict.
• Explicit module re-exports — export alias.Symbol forwards original
  declarations through module facades without wrapper code; collisions, cycles
  and package boundaries are diagnosed, and sprig api reports the originating
  module.
• Expression match — match can be used as an expression with strict
  contextual result types, shared exhaustive/binder rules, side-effect-safe
  scrutinee evaluation, and checked effects.
• Adversarial correctness pass — ten confirmed defects fixed with
  independent regressions: inferred global binding soundness, generated Java
  type-name collisions, default field effect propagation, finally completion
  analysis, bare-CR layout positions, JVM source-vs-bridge method resolution,
  unnamed-package imports rejected before javac, managed-installer ZIP
  hardening (links, traversal, duplicate entries), indexed-assignment key/index
  type checking (writes now enforce the same compatibility the read path
  already enforced), and null-safe nullable scalar equality (Int32?/Float32?
  no longer use Java object identity and null operands no longer throw).
• Evaluation and mutation contracts — binary operands evaluate left to
  right, each exactly once, so in no longer inherits Java's
  container.contains(element) argument order; compound assignment through a
  map index requires an existing key and raises a catchable Error when the
  key is missing instead of a Java unboxing failure.
• Managed SDK install and upgrade — versioned user-scoped installs under
  ~/.sprig with checksum + smoke verification, atomic current switch and
  sprig upgrade/upgrade --check on Linux/macOS; source checkouts and
  unmanaged ZIPs are refused with actionable diagnostics.
• Unicode code-point strings — length, indexing, charAt, codeAt,
  substring, indexOf and iteration count Unicode code points; there is no
  Char type, and the JVM boundary remains a single UTF-16 unit.
• sprig api for Sprig and Java — compiler-resolved module/project metadata
  with --member, plus existing Java class inspection; neither executes
  application code. capabilities gained feature guidance and explain richer
  repair metadata.
• Libraries and applications — sprig-cli, sprig-sqlite (including
  migrations) and sprig-web, with the mini-web, ledger, sqlite-migrations,
  json-select and agent-tool examples, all exercised by the release gates.
• Agent-facing diagnostics — every stable SPR-* code has a concise
  meaning plus structured sprig explain --json guidance (causes, safe fixes,
  related codes, help topic), and capability claims point to executable
  regression evidence enforced by a consistency gate. Repair metadata remains
  guidance only: machineApplicable stays false, with no automatic semantic
  rewrites.
• Repository hygiene — milestone plans and blind-trial evidence are archived,
  audit regressions are permanent under tests/adversarial/regressions/, and
  docs/README.md defines the documentation trust order.

Try it

Extract sprig-v0.4.0-alpha.1-jdk.zip after checking its .sha256, add bin
to PATH, and install JDK17+ (the SDK does not bundle Java):

sprig version
sprig init my-tool
cd my-tool
sprig resolve
sprig run
sprig fmt --check

On Windows use bin\sprig.cmd; on Unix bin/sprig. See the
formatter, re-exports,
match expressions and
known limitations contracts.

Compatibility and limits

No existing syntax, numeric, nullability, generic or effect contract was
redesigned. Lock schema 3 and the project model are unchanged. Publishing and
registry/authentication, LSP/IDE, generic inference/variance, interfaces and
self-hosting remain absent; Windows stays an experimental, non-blocking preview.
Types do not prove numerical stability, and Java generic/array/varargs interop
remains limited. sprig api and sprig check never execute application code.