chore(ci): use a shared rust cache

.github/workflows/coverage.yml

@@ -39,6 +39,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Generate code coverage (including doc tests)
         run: |
           cargo llvm-cov --all-features --workspace --no-report nextest

.github/workflows/fuzz.yml

@@ -26,6 +26,8 @@ jobs:
       with:
         cache-targets: true # cache build artifacts
         cache-bin: true # cache the ~/.cargo/bin directory
+        shared-key: shared-${{ runner.os }}
+        save-if: ${{ github.ref == 'refs/heads/main' }}
     - run: |
         set -e
         # cargo bolero list outputs {"package":"package-name","test":"test-name"}

.github/workflows/lint.yml

@@ -33,6 +33,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - run: cargo fmt --all -- --check
   clippy:
     name: "clippy #${{ matrix.platform }} ${{ matrix.rust_version }}"
@@ -54,6 +56,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: Run clippy on ${{ matrix.platform }} ${{ matrix.rust_version }}
         shell: bash
         run: |

.github/workflows/miri.yml

@@ -30,6 +30,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - run: MIRIFLAGS="-Zmiri-disable-isolation" cargo miri nextest run --partition count:${{ matrix.partition }}/5
       # We need to disable isolation because
       # "unsupported operation: `clock_gettime` with `REALTIME` clocks not available when isolation is enabled"

.github/workflows/pr-metadata-docs-and-deps.yml

@@ -103,6 +103,8 @@ jobs:
     - uses: Swatinem/rust-cache@f13886b937689c021905a6b90929199931d60db1 # v2.8.1
       with:
         cache-targets: true
+        shared-key: shared-${{ runner.os }}
+        save-if: ${{ github.ref == 'refs/heads/main' }}
     - uses: dtolnay/rust-toolchain@stable
     - name: Check missing docs
       id: missing-docs
@@ -274,6 +276,8 @@ jobs:
     - uses: Swatinem/rust-cache@f13886b937689c021905a6b90929199931d60db1 # v2.8.1
       with:
         cache-targets: true
+        shared-key: shared-${{ runner.os }}
+        save-if: ${{ github.ref == 'refs/heads/main' }}
     - uses: dtolnay/rust-toolchain@stable
     - uses: taiki-e/cache-cargo-install-action@7447f04c51f2ba27ca35e7f1e28fab848c5b3ba7 # 2.3.1
       with:

.github/workflows/pr-title-semver-check.yml

@@ -99,6 +99,8 @@ jobs:
         uses: Swatinem/rust-cache@f13886b937689c021905a6b90929199931d60db1 # 2.8.1
         with:
           cache-targets: true
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
 
       - name: Install dependencies
         run: |

.github/workflows/release-proposal-dispatch.yml

@@ -142,6 +142,8 @@ jobs:
       - uses: Swatinem/rust-cache@f13886b937689c021905a6b90929199931d60db1 # v2.8.1
         with:
           cache-targets: true
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - uses: dtolnay/rust-toolchain@nightly
         with:
           toolchain: nightly-2026-02-08

.github/workflows/test.yml

@@ -53,6 +53,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: "Remove nextest CI report"
         shell: bash
         run: rm -rf target/nextest/ci/junit.xml
@@ -193,6 +195,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: "Generate profiling FFI"
         shell: bash
         env:
@@ -308,6 +312,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - run: cargo install cross || true
       - run: cross build --workspace --target x86_64-unknown-linux-gnu --exclude builder
       - run: cross test --workspace --features libdd-crashtracker/generate-unit-test-files --target x86_64-unknown-linux-gnu --exclude builder  -- --skip "::single_threaded_tests::" --skip "tracing_integration_tests::"

.github/workflows/verify-proto-files.yml

@@ -52,6 +52,8 @@ jobs:
         with:
           cache-targets: true # cache build artifacts
           cache-bin: true # cache the ~/.cargo/bin directory
+          shared-key: shared-${{ runner.os }}
+          save-if: ${{ github.ref == 'refs/heads/main' }}
       - name: diff pb.rs
         working-directory: libdd-trace-protobuf
         run: |