Add real wasm32 smoke tests and CI job

.cargo/config.toml

@@ -6,3 +6,17 @@
 xtask = "run --package xtask --"
 dev-setup = "xtask dev-setup"
 create-worktree = "xtask create-worktree"
+
+[target.wasm32-unknown-unknown]
+runner = "wasm-bindgen-test-runner"
+# Mirror the rustflags used by wasm-quarto-hub-client/.cargo/config.toml so any
+# wasm32 build invoked from the workspace root (e.g. the pampa wasm_lua test)
+# gets the same panic strategy and ABI. Without panic=unwind plus the
+# exception-handling target feature, wasm-c-shim's catch_unwind-based
+# replacement for Lua's setjmp/longjmp can't catch panics, and any Lua throw
+# during mlua initialization aborts the wasm module.
+rustflags = [
+    "-C", "target-feature=+bulk-memory,+exception-handling",
+    "-C", "panic=unwind",
+    "-Zwasm-c-abi=spec",
+]

.claude/rules/wasm.md

@@ -52,3 +52,14 @@ stages run sequentially within a single task.
 If you find yourself wanting to drop `?Send`, that is a signal something
 is wrong with the design of the calling context, not with the trait.
 Stop and ask before changing it.
+
+## Verify WASM tests when editing WASM code
+
+When modifying any of these files, update `crates/pampa/tests/wasm_lua.rs`:
+- `crates/pampa/src/lua/filter.rs` (cfg(target_arch = "wasm32") blocks)
+- `crates/pampa/src/lua/shortcode.rs` (cfg(target_arch = "wasm32") blocks)
+- `crates/pampa/src/lua/io_wasm.rs`
+- `crates/pampa/src/lua/os_wasm.rs`
+
+WASM tests can't run locally on Windows — they run in Linux CI.
+See `dev-docs/wasm.md` for the local run command (Linux/macOS).

.github/workflows/test-suite.yml

@@ -179,3 +179,39 @@ jobs:
         run: cargo nextest run --tests --cargo-profile ci
         env:
           RUSTFLAGS: "-D warnings"
+
+  wasm-tests:
+    name: WASM Tests
+    runs-on: ubuntu-latest
+    # Uses the pinned toolchain from rust-toolchain.toml, which is already a
+    # nightly with rust-src (required by -Zbuild-std) and the wasm32 target.
+    # Do NOT override with latest nightly: bd-at72 pinned the toolchain because
+    # newer nightlies SIGSEGV in LLVM ThinLTO when building this workspace for
+    # wasm32-unknown-unknown. (The E0152 duplicate-lang-item conflict between
+    # the prebuilt wasm32 sysroot and -Zbuild-std that this job originally
+    # worked around no longer reproduces on the pinned toolchain.)
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Set up Clang
+        uses: egor-tensin/setup-clang@v1
+        with:
+          version: latest
+          platform: x64
+
+      - name: Rust cache
+        uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: rust-wasm-tests
+
+      - name: Install wasm-bindgen-cli
+        run: cargo xtask dev-setup
+
+      - name: Run WASM tests
+        run: |
+          CC_wasm32_unknown_unknown=clang \
+          CFLAGS_wasm32_unknown_unknown="-isystem ${{ github.workspace }}/crates/wasm-quarto-hub-client/wasm-sysroot -fno-builtin" \
+          cargo test -p pampa --test wasm_lua --target wasm32-unknown-unknown \
+            --no-default-features --features lua-filter -Zbuild-std=std,panic_unwind,panic_abort

Cargo.toml

@@ -274,6 +274,13 @@ verbose_file_reads = "warn"
 
 [patch.crates-io]
 lua-src = { path = "crates/lua-src-wasm" }
+# Neutralize tree-sitter-language's upstream wasm32 stdio/stdlib/string C
+# stubs so wasm-c-shim is the single source of truth for C stdlib symbols
+# in workspace wasm32 builds (the pampa wasm_lua tests). Same patch as
+# wasm-quarto-hub-client's; identical Rust source on native targets, and
+# its build.rs is a no-op off-wasm32. See
+# claude-notes/plans/2026-04-20-wasm-shim-merge.md.
+tree-sitter-language = { path = "crates/tree-sitter-language-wasm-shim" }
 # Fork of runtimelib that adds venv-aware kernelspec discovery
 # (`data_dirs_with_jupyter_paths`, `find_kernelspec_with_jupyter_paths`)
 # and threads `searched_paths` through `RuntimeError::KernelNotFound`.