Add Copilot coding agent setup steps and inner loop guidance (microsoft#3099)

Add .github/workflows/copilot-setup-steps.yml to give the Copilot coding
agent a working Rust toolchain, cargo-nextest, and restore-packages
(protoc + build deps) so it can validate changes locally before pushing.

Author: jstarks

.github/copilot-instructions.md

@@ -117,3 +117,28 @@ This project uses the **Rust 2024 edition** (`edition = "2024"` in root
   hand-edit them. Run `cargo xflowey regen` to regenerate.
 - **flowey nodes**: Use `flowey::shell_cmd!` and `rt.sh` inside flowey
   nodes — not `xshell::cmd!` or `xshell::Shell::new`.
+
+## Autonomous Agent Inner Loop
+
+When running as a coding agent (GitHub Copilot coding agent or similar),
+follow this validation loop **before pushing each commit**. This covers
+the common early CI failures (including the fmt + clippy checks from job0)
+locally, avoiding slow push-and-wait cycles.
+
+1. **Identify modified packages.** For each file you changed, find the
+   crate's `Cargo.toml` and note the package name.
+2. **Check compilation:** `cargo check -p <package>` — fast type-check.
+3. **Clippy:** `cargo clippy --all-targets -p <package>` — lint.
+4. **Doc:** `cargo doc --no-deps -p <package>` — catch doc errors.
+5. **Unit tests:** `cargo nextest run -p <package>` — run the crate's
+   tests. If nextest is not installed, use `cargo test -p <package>`.
+6. **Formatting:** `cargo xtask fmt --fix` — run last, since earlier
+   fixes may introduce formatting changes.
+
+If any step fails, fix the issue and re-run from that step. Do not push
+until all six steps pass.
+
+**Cost notes:** Steps 2–5 are scoped to the modified package (`-p`),
+so they are fast even in this large workspace. Step 6 runs workspace-wide
+but is also fast. The full cycle typically takes under 2 minutes for
+a single-crate change.

.github/workflows/copilot-setup-steps.yml

@@ -0,0 +1,41 @@
+name: "Copilot Setup Steps"
+
+# Validate the setup steps when they change, and allow manual testing.
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+jobs:
+  # This job name is required — the Copilot coding agent looks for it by name.
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+
+      # Install the exact Rust toolchain used by CI.
+      - name: Install Rust toolchain
+        run: |
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs \
+            | sh -s -- --default-toolchain=1.94.0 -y
+          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
+
+      # Install cargo-nextest so the agent can run unit tests.
+      # Keep this version in sync with NEXTEST in
+      # flowey/flowey_lib_hvlite/src/_jobs/cfg_versions.rs
+      - name: Install cargo-nextest
+        run: |
+          curl -LsSf https://get.nexte.st/0.9.101/linux | tar zxf - -C "$HOME/.cargo/bin"
+
+      # Restore protoc and other build dependencies via the canonical
+      # flowey pipeline. This compiles flowey_hvlite first, then downloads
+      # protoc, sysroots, firmware, and test kernels.
+      - name: Restore packages
+        run: cargo xflowey restore-packages --no-compat-igvm

flowey/flowey_hvlite/src/pipelines/restore_packages.rs

@@ -12,6 +12,12 @@ pub struct RestorePackagesCli {
     ///
     /// If none are specified, defaults to just the current host architecture.
     arch: Vec<CommonArchCli>,
+
+    /// Skip downloading released OpenHCL IGVM files used for compatibility testing.
+    ///
+    /// This avoids the need for `gh` CLI authentication.
+    #[clap(long)]
+    no_compat_igvm: bool,
 }
 
 impl IntoPipeline for RestorePackagesCli {
@@ -21,7 +27,11 @@ impl IntoPipeline for RestorePackagesCli {
         );
 
         let mut pipeline = Pipeline::new();
-        let (pub_last_release_igvm_files, _) = pipeline.new_artifact("last-release-igvm-files");
+        let pub_last_release_igvm_files = if self.no_compat_igvm {
+            None
+        } else {
+            Some(pipeline.new_artifact("last-release-igvm-files").0)
+        };
         let mut job = pipeline
             .new_job(
                 FlowPlatform::host(backend_hint),
@@ -59,7 +69,7 @@ impl IntoPipeline for RestorePackagesCli {
             |ctx| flowey_lib_hvlite::_jobs::local_restore_packages::Request {
                 arches,
                 done: ctx.new_done_handle(),
-                release_artifact: ctx.publish_artifact(pub_last_release_igvm_files),
+                release_artifact: pub_last_release_igvm_files.map(|a| ctx.publish_artifact(a)),
             },
         );
         job.finish();

flowey/flowey_lib_hvlite/src/_jobs/local_restore_packages.rs

@@ -11,7 +11,8 @@ flowey_request! {
     pub struct Request{
         pub arches: Vec<CommonArch>,
         pub done: WriteVar<SideEffect>,
-        pub release_artifact: ReadVar<PathBuf>,
+        /// If `None`, skip downloading OpenHCL IGVM release files.
+        pub release_artifact: Option<ReadVar<PathBuf>>,
     }
 }
 
@@ -85,18 +86,20 @@ impl SimpleFlowNode for Node {
                 }
             }
 
-            deps.push(
-                ctx.reqv(
-                    |v| crate::init_openvmm_magicpath_release_openhcl_igvm::resolve::Request {
-                        arch,
-                        release_version:
-                            crate::download_release_igvm_files_from_gh::OpenhclReleaseVersion::latest(),
-                        release_artifact:release_artifact.clone(),
-                        done: v,
-                    },
-                )
-                .into_side_effect(),
-            );
+            if let Some(release_artifact) = &release_artifact {
+                deps.push(
+                    ctx.reqv(
+                        |v| crate::init_openvmm_magicpath_release_openhcl_igvm::resolve::Request {
+                            arch,
+                            release_version:
+                                crate::download_release_igvm_files_from_gh::OpenhclReleaseVersion::latest(),
+                            release_artifact: release_artifact.clone(),
+                            done: v,
+                        },
+                    )
+                    .into_side_effect(),
+                );
+            }
         }
 
         ctx.emit_side_effect_step(deps, [done]);