Ensure formatting during CI checks

In order to ensure that we don't get odd formatting changes
mixed in with future PRs, verify the formatting during the CI
run if all tests pass.

Signed-off-by: Daniel Silverstone <[email protected]>

Author: kinnison

README.md

@@ -728,6 +728,10 @@ affecting any existing installation. Remember to keep those two environment vari
 set when running your compiled `rustup-init` or the toolchains it installs, but _unset_
 when rebuilding `rustup` itself.
 
+We use `rustfmt` to keep our codebase consistently formatted.  Please ensure that
+you have correctly formatted your code (most editors will do this automatically
+when saving) or it may not pass the CI tests.
+
 Unless you explicitly state otherwise, any contribution intentionally
 submitted for inclusion in the work by you, as defined in the
 Apache-2.0 license, shall be dual licensed as above, without any

appveyor.yml

@@ -70,6 +70,7 @@ install:
   - where gcc rustc cargo
   - rustc -vV
   - cargo -vV
+  - rustfmt -vV
 
 build: false
 
@@ -79,6 +80,7 @@ test_script:
   - cargo test --release --target %TARGET% %FEATURES%
   - if defined BUILD_MSI pushd src\rustup-win-installer && cargo build --release --target %TARGET% & popd
   - if defined BUILD_MSI pushd src\rustup-win-installer\msi && powershell .\build.ps1 -Target %TARGET% & popd
+  - cargo fmt --all -- --check
 
 notifications:
   - provider: Webhook

ci/run.sh

@@ -6,6 +6,7 @@ echo "toolchain versions\n------------------"
 
 rustc -vV
 cargo -vV
+rustfmt -vV
 
 cargo build --locked -v --release --target $TARGET --features vendored-openssl
 
@@ -14,3 +15,7 @@ if [ -z "$SKIP_TESTS" ]; then
   cargo test --release -p rustup-dist --target $TARGET --features vendored-openssl
   cargo test --release --target $TARGET --features vendored-openssl
 fi
+
+# Check the formatting last because test failures are more interesting to have
+# discovered for contributors lacking some platform access for testing beforehand
+cargo fmt --all -- --check