Add tests for bisect.

.github/workflows/ci.yml

@@ -310,7 +310,7 @@ jobs:
 
   # we should always have an artifact from a previous build.
   remote:
-    needs: [shellcheck, test, generate-matrix, check]
+    needs: [shellcheck, test, check]
     runs-on: ubuntu-latest
     env:
       TARGET: aarch64-unknown-linux-gnu
@@ -319,8 +319,18 @@ jobs:
       - uses: ./.github/actions/setup-rust
       - run: ./ci/remote.sh
 
+  bisect:
+    needs: [shellcheck, test, check]
+    runs-on: ubuntu-latest
+    env:
+      TARGET: aarch64-unknown-linux-gnu
+    steps:
+      - uses: actions/checkout@v3
+      - uses: ./.github/actions/setup-rust
+      - run: ./ci/bisect.sh
+
   publish:
-    needs: [build, check, fmt, clippy, cargo-deny, remote]
+    needs: [build, check, fmt, clippy, cargo-deny, remote, bisect]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3

ci/bisect.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# shellcheck disable=SC1091,SC1090
+
+# test to see that custom toolchains work
+
+set -x
+set -eo pipefail
+
+if [[ -z "${TARGET}" ]]; then
+    export TARGET="aarch64-unknown-linux-gnu"
+fi
+
+source=$(dirname "${BASH_SOURCE[0]}")
+. "${source}"/shared.sh
+
+main() {
+    local td=
+    local err=
+
+    retry cargo fetch
+    cargo install --force --path .
+    cargo install cargo-bisect-rustc
+
+    td="$(mktemp -d)"
+    git clone --depth 1 https://github.com/cross-rs/rust-cpp-hello-word "${td}"
+
+    pushd "${td}"
+    retry cargo fetch
+    echo '#!/usr/bin/env bash
+export CROSS_CUSTOM_TOOLCHAIN=1
+exec cross run --target '"${TARGET}" > bisect.sh
+    chmod +x bisect.sh
+
+    if ! err=$(cargo bisect-rustc --script=./bisect.sh --target "${TARGET}" 2>&1 >/dev/null); then
+        if [[ "${err}" != *"does not reproduce the regression"* ]]; then
+            echo "${err}"
+            exit 1
+        fi
+    else
+        echo "should have failed, instead succeeded" 1>&2
+        exit 1
+    fi
+    popd
+
+    rm -rf "${td}"
+}
+
+main

ci/remote.sh

@@ -1,6 +1,8 @@
 #!/usr/bin/env bash
 # shellcheck disable=SC1091,SC1090
 
+# test to see that remote docker support works.
+
 set -x
 set -eo pipefail
 
@@ -13,7 +15,6 @@ source=$(dirname "${BASH_SOURCE[0]}")
 . "${source}"/shared.sh
 
 main() {
-    local td=
     local err=
 
     retry cargo fetch