ci: migrate remaining pinned actions to node24 (#4023)

* ci: migrate remaining pinned actions to node24

actions/cache@v4 and mlugg/setup-zig@v2.2.1 still target Node 20, which
GitHub removes from runners on 2026-09-23. Bump actions/cache to v6.1.0 and
replace mlugg/setup-zig with vercel-labs/setup-zig@v1.0.2.

vercel-labs/setup-zig takes only `version`, so the use-cache/cache-size-limit
tuning and Zig global-cache reuse are dropped. See the PR for alternatives.

* ci: restore zig caching for vercel setup-zig

vercel-labs/setup-zig has no cache controls, so redirect the Zig global cache
into the workspace .zig-cache and run the Zig build cache step on Linux too.

Drop this commit if we switch to a setup action that owns Zig caching, e.g.
step-security/setup-zig or xyzzylabs/setup-zig.

1 files changed, 10 insertions, 10 deletions

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a481594e..ed8f9695 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,6 +14,11 @@ env:
   # Keep file/line backtraces without generating type and variable debug information.
   CARGO_PROFILE_DEV_DEBUG: "1"
   CARGO_PROFILE_TEST_DEBUG: "1"
+  # vercel-labs/setup-zig does not cache the Zig global cache, so redirect it into the
+  # workspace .zig-cache that the Zig build cache steps persist. Remove this (and the
+  # widened condition on "Restore Zig build cache") if we switch to a setup action that
+  # owns Zig caching, e.g. step-security/setup-zig. See PR #4023.
+  ZIG_GLOBAL_CACHE_DIR: ${{ github.workspace }}/.zig-cache
 
 concurrency:
   group: ci-${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
@@ -89,12 +94,9 @@ jobs:
           bun-version: 1.3.14
 
       - name: Install Zig
-        uses: mlugg/setup-zig@d1434d08867e3ee9daa34448df10607b98908d29 # v2.2.1
+        uses: vercel-labs/setup-zig@83c1594f26b86da8a9a8ddd9b5ee5f3af0f96943 # v1.0.2
         with:
           version: 0.16.0
-          use-cache: ${{ runner.os == 'Linux' }}
-          # Linux builds both SIMD/ReleaseFast and scalar/ReleaseSafe variants.
-          cache-size-limit: 4096
 
       # Zig's C-header cache keys include the compiler installation path.
       - name: Stabilize Zig installation path on Unix
@@ -116,8 +118,7 @@ jobs:
           "ZIG=$(Join-Path $stable 'zig.exe')" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
 
       - name: Restore Zig build cache
-        if: runner.os == 'macOS' || matrix.kind == 'windows'
-        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         with:
           path: .zig-cache
           key: zig-build-v1-${{ runner.os }}-${{ runner.arch }}-0.16.0-${{ github.run_id }}-${{ github.run_attempt }}
@@ -134,7 +135,7 @@ jobs:
       # rebuilds workspace targets; only rustc's validated query state is retained.
       - name: Restore Windows incremental compiler state
         if: matrix.kind == 'windows'
-        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         with:
           path: target/debug/incremental
           key: ci-incremental-v1-${{ runner.os }}-${{ runner.arch }}-${{ env.RUST_TOOLCHAIN_VERSION }}-${{ env.CARGO_PROFILE_DEV_DEBUG }}-${{ env.CARGO_PROFILE_TEST_DEBUG }}-${{ hashFiles('Cargo.lock', 'Cargo.toml', '.cargo/config.toml', 'build.rs') }}-${{ github.sha }}
@@ -192,10 +193,9 @@ jobs:
           targets: x86_64-pc-windows-msvc
 
       - name: Install Zig
-        uses: mlugg/setup-zig@d1434d08867e3ee9daa34448df10607b98908d29 # v2.2.1
+        uses: vercel-labs/setup-zig@83c1594f26b86da8a9a8ddd9b5ee5f3af0f96943 # v1.0.2
         with:
           version: 0.16.0
-          use-cache: false
 
       - name: Stabilize Zig installation path
         shell: pwsh
@@ -207,7 +207,7 @@ jobs:
           "ZIG=$(Join-Path $stable 'zig.exe')" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
 
       - name: Restore Zig build cache
-        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
+        uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         with:
           path: .zig-cache
           key: zig-build-v1-conpty-package-windows-2022-${{ runner.arch }}-0.16.0-${{ github.run_id }}-${{ github.run_attempt }}