perf(ci): implement granular steps with persistent workspace cache (#85)

* fix(devcontainer): switch base image to bookworm for glibc compatibility

* refactor(ci): implement sequential Build & Verify jobs with granular steps

* refactor(ci): use single-job sequential steps with local image reuse

* perf(devcontainer): remove explicit CARGO_TARGET_DIR to enable incremental CI builds

* perf(ci): persist CARGO_HOME in workspace for true incremental granular builds

* debug(ci): add path and env logging to identify cache sharing issues

* debug(ci): add persistence check for target directory across steps

* perf(ci): use explicit CARGO_TARGET_DIR and CARGO_INCREMENTAL for granular steps

* perf(ci): use persistent container via @devcontainers/cli for true incremental builds

* debug(ci): Phase 1 diagnostic - verify build cache within single step

* perf(ci): implement granular devcontainers/ci steps with persistent workspace paths

Author: sonesuke

.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/devcontainers/rust:1-bullseye
+FROM mcr.microsoft.com/devcontainers/rust:1-bookworm
 
 # Install Node.js and other dependencies as root
 RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
@@ -21,12 +21,8 @@ RUN chown -R vscode:vscode /usr/local/cargo /usr/local/rustup
 # Switch to vscode user
 USER vscode
 
-# Set CARGO_HOME to a location in user home to avoid permission issues in CI
-# and add it to PATH
-# ENV CARGO_HOME=/home/vscode/.cargo (Deferred until runtime)
-ENV PATH=$CARGO_HOME/bin:$PATH
-# Set CARGO_TARGET_DIR to a location in user home that is safe from volume mounts
-ENV CARGO_TARGET_DIR=/home/vscode/.cargo-target
+# Ensure pre-installed tools are always in PATH even if CARGO_HOME is overridden at runtime
+ENV PATH=/usr/local/cargo/bin:$PATH
 
 # No pre-build (cache is disabled by user request)
 

.github/workflows/ci.yml

@@ -15,7 +15,7 @@ permissions:
   packages: read
 
 jobs:
-  build:
+  verify:
     name: Build & Verify
     runs-on: ubuntu-latest
     steps:
@@ -33,10 +33,39 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
+      - name: Build & Initialize Dev Container
+        uses: devcontainers/ci@v0.3
+        env:
+          CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
+        with:
+          imageName: ghcr.io/${{ github.repository }}/docgraph-dev
+          cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
+          push: never
+          runCmd: cargo build
+
+      - name: Docgraph Check
+        uses: devcontainers/ci@v0.3
+        env:
+          CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
+        with:
+          imageName: ghcr.io/${{ github.repository }}/docgraph-dev
+          cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
+          push: never
+          runCmd: cargo run -- check ./doc
+
       - name: Rust Format Check
         uses: devcontainers/ci@v0.3
         env:
           CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
         with:
           imageName: ghcr.io/${{ github.repository }}/docgraph-dev
           cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
@@ -47,6 +76,9 @@ jobs:
         uses: devcontainers/ci@v0.3
         env:
           CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
         with:
           imageName: ghcr.io/${{ github.repository }}/docgraph-dev
           cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
@@ -57,6 +89,9 @@ jobs:
         uses: devcontainers/ci@v0.3
         env:
           CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
         with:
           imageName: ghcr.io/${{ github.repository }}/docgraph-dev
           cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
@@ -69,6 +104,9 @@ jobs:
         uses: devcontainers/ci@v0.3
         env:
           CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
         with:
           imageName: ghcr.io/${{ github.repository }}/docgraph-dev
           cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
@@ -82,21 +120,15 @@ jobs:
         uses: devcontainers/ci@v0.3
         env:
           CI: true
+          CARGO_HOME: ${{ github.workspace }}/.cargo
+          CARGO_TARGET_DIR: ${{ github.workspace }}/target
+          CARGO_INCREMENTAL: 1
         with:
           imageName: ghcr.io/${{ github.repository }}/docgraph-dev
           cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
           push: never
           runCmd: cargo llvm-cov --all-features --workspace --lcov --output-path lcov.info
 
-      - name: Docgraph Check
-        uses: devcontainers/ci@v0.3
-        env:
-          CI: true
-        with:
-          imageName: ghcr.io/${{ github.repository }}/docgraph-dev
-          cacheFrom: ghcr.io/${{ github.repository }}/docgraph-dev
-          push: never
-          runCmd: cargo run -- check ./doc
 
       - name: Upload coverage report
         uses: actions/upload-artifact@v6
@@ -105,3 +137,5 @@ jobs:
           path: lcov.info
 
 
+
+