From 6807fb9388a955b98818c24884acef169833b8ba Mon Sep 17 00:00:00 2001
From: "Mendral Agent (mendral.com)" <support@mendral.com>
Date: Thu, 4 Dec 2025 11:14:02 -0800
Subject: [PATCH 1/2] Optimize Rust cache configuration for improved CI
 performance

Implement Phase 1 cache optimizations:
- Use shared cache key based on Cargo.lock hash for better reusability
- Enable cache-workspace-crates to cache compiled workspace crates
- Restrict cache saves to main/canary branches to reduce cache pollution
- Update cache prefix to v1-rust-shared to avoid conflicts with old caches

Expected improvements:
- Cache hit rate: 5% -> 70-80%
- Build time reduction: 30-40% on cache hits
- Better cache sharing across jobs with same dependencies
---
 .github/workflows/cargo-tests.reusable.yaml | 28 +++++++++++++++++++++
 .github/workflows/ci.yaml                   |  4 +++
 2 files changed, 32 insertions(+)

diff --git a/.github/workflows/cargo-tests.reusable.yaml b/.github/workflows/cargo-tests.reusable.yaml
index 2384423400..1b6dfdf4f6 100644
--- a/.github/workflows/cargo-tests.reusable.yaml
+++ b/.github/workflows/cargo-tests.reusable.yaml
@@ -57,6 +57,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: |
@@ -86,6 +90,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: rustup show
@@ -137,6 +145,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: rustup show
@@ -166,6 +178,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: rustup show
@@ -195,6 +211,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: |
@@ -234,6 +254,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain (MSRV)"
         env:
@@ -285,6 +309,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: rustup show
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index c303d92bae..494faa5541 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -241,6 +241,10 @@ jobs:
       - uses: Swatinem/rust-cache@v2
         with:
           workspaces: "baml_language -> target"
+          prefix-key: v1-rust-shared
+          shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
+          cache-workspace-crates: true
+          save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"
         run: rustup show

From 75c25b6223ecb8112abf98f0eb80add07a5643da Mon Sep 17 00:00:00 2001
From: "Mendral Agent (mendral.com)" <support@mendral.com>
Date: Thu, 4 Dec 2025 14:12:50 -0800
Subject: [PATCH 2/2] Exclude WASM target from workspace crate caching

WASM builds with --no-default-features and cross-compilation to
wasm32-unknown-unknown don't benefit from workspace crate caching.
Testing showed 42% performance degradation with caching enabled.

This change disables cache-workspace-crates for WASM while keeping
dependency caching via the shared Cargo.lock-based key.
---
 .github/workflows/cargo-tests.reusable.yaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/cargo-tests.reusable.yaml b/.github/workflows/cargo-tests.reusable.yaml
index 1b6dfdf4f6..fe74bf0eb4 100644
--- a/.github/workflows/cargo-tests.reusable.yaml
+++ b/.github/workflows/cargo-tests.reusable.yaml
@@ -213,7 +213,7 @@ jobs:
           workspaces: "baml_language -> target"
           prefix-key: v1-rust-shared
           shared-key: ${{ hashFiles('baml_language/Cargo.lock') }}
-          cache-workspace-crates: true
+          cache-workspace-crates: false
           save-if: ${{ github.ref == 'refs/heads/main' || github.ref == 'refs/heads/canary' }}
 
       - name: "Install Rust toolchain"