Add git pre-push hook

.github/workflows/ci.yml

@@ -328,13 +328,7 @@ jobs:
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
       - name: Check Rust formatting
-        run: |
-          set -eo pipefail
-          cargo fmt --check -p zerocopy
-          cargo fmt --check -p zerocopy-derive
-          shopt -s globstar
-          rustfmt --check tests/**/*.rs
-          rustfmt --check zerocopy-derive/tests/**/*.rs
+        run: ./ci/check_fmt.sh
 
   check_readme:
     needs: generate_cache
@@ -347,16 +341,7 @@ jobs:
         uses: ./.github/actions/cache
 
       - name: Check README.md
-        run: |
-          set -eo pipefail
-
-          # Install again in case the installation failed during the
-          # `generate_cache` step. We treat that step as best-effort and
-          # suppress all errors from it.
-          cargo install cargo-readme --version 3.2.0
-
-          diff <(./generate-readme.sh) README.md
-          exit $?
+        run: ./ci/check_readme.sh
 
   check_msrv:
     needs: generate_cache
@@ -378,25 +363,7 @@ jobs:
       #   that compiling zerocopy with the `derive` feature enabled would fail
       #   on its own published MSRV)
       - name: Check MSRVs match
-        run: |
-          set -eo pipefail
-
-          # Usage: msrv <crate-name>
-          function msrv {
-            cargo metadata --format-version 1 | jq -r ".packages[] | select(.name == \"$1\").rust_version"
-          }
-
-          ver_zerocopy=$(msrv zerocopy)
-          ver_zerocopy_derive=$(msrv zerocopy-derive)
-
-          if [[ "$ver_zerocopy" == "$ver_zerocopy_derive" ]]; then
-            echo "Same MSRV ($ver_zerocopy) found for zerocopy and zerocopy-derive." | tee -a $GITHUB_STEP_SUMMARY
-            exit 0
-          else
-            echo "Different MSRVs found for zerocopy ($ver_zerocopy) and zerocopy-derive ($ver_zerocopy_derive)." \
-              | tee -a $GITHUB_STEP_SUMMARY >&2
-            exit 1
-          fi
+        run: ./ci/check_msrv.sh
 
   check_versions:
     needs: generate_cache
@@ -412,67 +379,8 @@ jobs:
       # depends exactly upon the current version of zerocopy-derive. See
       # `INTERNAL.md` for an explanation of why we do this.
       - name: Check crate versions match
-        run: |
-          set -eo pipefail
-
-          # Usage: version <crate-name>
-          function version {
-            cargo metadata --format-version 1 | jq -r ".packages[] | select(.name == \"$1\").version"
-          }
-
-          ver_zerocopy=$(version zerocopy)
-          ver_zerocopy_derive=$(version zerocopy-derive)
-
-          # Usage: dependency-version <kind> <target>
-          function dependency-version {
-            KIND="$1"
-            TARGET="$2"
-            cargo metadata --format-version 1 \
-              | jq -r ".packages[] | select(.name == \"zerocopy\").dependencies[] | select((.name == \"zerocopy-derive\") and .kind == $KIND and .target == $TARGET).req"
-          }
-
-          # The non-dev dependency version (kind `null` filters out the dev
-          # dependency, and target `null` filters out the targeted version).
-          zerocopy_derive_dep_ver=$(dependency-version null null)
-
-          # The non-dev dependency, targeted version (kind `null` filters out
-          # the dev dependency).
-          zerocopy_derive_targeted_ver=$(dependency-version null '"cfg(any())"')
-
-          # The dev dependency version (kind `"dev"` selects only the dev
-          # dependency).
-          zerocopy_derive_dev_dep_ver=$(dependency-version '"dev"' null)
-
-          function assert-match {
-            VER_A="$1"
-            VER_B="$2"
-            SUCCESS_MSG="$3"
-            FAILURE_MSG="$4"
-            if [[ "$ver_zerocopy" == "$ver_zerocopy_derive" ]]; then
-              echo "$SUCCESS_MSG" | tee -a $GITHUB_STEP_SUMMARY
-            else
-              echo "$FAILURE_MSG" | tee -a $GITHUB_STEP_SUMMARY >&2
-              exit 1
-            fi
-          }
-
-          assert-match "$ver_zerocopy" "$ver_zerocopy_derive" \
-            "Same crate version ($ver_zerocopy) found for zerocopy and zerocopy-derive." \
-            "Different crate versions found for zerocopy ($ver_zerocopy) and zerocopy-derive ($ver_zerocopy_derive)."
-
-          # Note the leading `=` sign - the dependency needs to be an exact one.
-          assert-match "=$ver_zerocopy_derive" "$zerocopy_derive_dep_ver" \
-            "zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dep_ver)." \
-            "zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dep_ver) than the one in-tree ($ver_zerocopy_derive)."
-
-          # Note the leading `=` sign - the dependency needs to be an exact one.
-          assert-match "=$ver_zerocopy_derive" "$zerocopy_derive_dev_dep_ver" \
-            "In dev mode, zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dev_dep_ver)." \
-            "In dev mode, zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dev_dep_ver) than the one in-tree ($ver_zerocopy_derive)."
-
-          assert-match "$zerocopy_derive_dep_ver" "$zerocopy_derive_targeted_ver" \
-            "Same crate version ($zerocopy_derive_dep_ver) found for optional and targeted zerocopy-derive dependency." \
-            "Different crate versions found for optional ($zerocopy_derive_dep_ver) and targeted ($zerocopy_derive_targeted_ver) dependency."
+        run: ./ci/check_versions.sh
+
   generate_cache:
     runs-on: ubuntu-latest
     name: Generate cache
@@ -511,22 +419,8 @@ jobs:
         run: go install github.com/mikefarah/yq/v4@latest
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
       - name: Run check
-        run: |
-          set -eo pipefail
+        run: ./ci/check_all_toolchains_tested.sh
 
-          # Check whether the set of toolchains tested in this file (other than
-          # 'msrv', 'stable', and 'nightly') is equal to the set of toolchains
-          # listed in the 'package.metadata.build-rs' section of Cargo.toml.
-          #
-          # If the inputs to `diff` are not identical, `diff` exits with a
-          # non-zero error code, which causes this script to fail (thanks to
-          # `set -e`).
-          diff \
-            <(cat .github/workflows/ci.yml | yq '.jobs.build_test.strategy.matrix.toolchain | .[]' | \
-              sort -u | grep -v '^\(msrv\|stable\|nightly\)$') \
-            <(cargo metadata --format-version 1 | \
-              jq -r ".packages[] | select(.name == \"zerocopy\").metadata.\"build-rs\" | keys | .[]" | \
-              sort -u)
   check-job-dependencies:
     runs-on: ubuntu-latest
     name: Check all-jobs-succeeded depends on all jobs
@@ -535,31 +429,7 @@ jobs:
         run: go install github.com/mikefarah/yq/v4@latest
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
       - name: Run dependency check
-        run: |
-          set -eo pipefail
-          jobs=$(for i in $(find .github -iname '*.yaml' -or -iname '*.yml')
-            do
-              # Select jobs that are triggered by pull request.
-              if yq -e '.on | has("pull_request")' "$i" 2>/dev/null >/dev/null
-              then
-                # This gets the list of jobs that all-jobs-succeed does not depend on.
-                comm -23 \
-                  <(yq -r '.jobs | keys | .[]' "$i" | sort | uniq) \
-                  <(yq -r '.jobs.all-jobs-succeed.needs[]' "$i" | sort | uniq)
-              fi
-
-            # The grep call here excludes all-jobs-succeed from the list of jobs that
-            # all-jobs-succeed does not depend on.  If all-jobs-succeed does
-            # not depend on itself, we do not care about it.
-            done | sort | uniq | (grep -v '^all-jobs-succeed$' || true)
-          )
-
-          if [ -n "$jobs" ]
-          then
-            missing_jobs="$(echo "$jobs" | tr ' ' '\n')"
-            echo "all-jobs-succeed missing dependencies on some jobs: $missing_jobs" | tee -a $GITHUB_STEP_SUMMARY
-            exit 1
-          fi
+        run: ./ci/check_job_dependencies.sh
 
   # Used to signal to branch protections that all other jobs have succeeded.
   all-jobs-succeed:

CONTRIBUTING.md

@@ -194,6 +194,21 @@ Commit messages should never contain references to any of:
       https://github.com/google/zerocopy/commit/789b3deb)
 1. Other entities which may not make sense to arbitrary future readers
 
+### Git hooks
+
+There is a pre-push git hook available at `./githooks/pre-push`. This hook runs
+some quick checks locally before pushing so that these same checks won't later
+fail during CI. The intention is to minimise needing to fix trivial breakages
+after having already just pushed (which can be annoying).
+
+Git won't use this hook automatically. If you would like to use it, set
+repository config `core.hooksPath` to `githooks`. This can be done by running
+(at repository root):
+
+```sh
+git config --local core.hooksPath githooks
+```
+
 ## Community Guidelines
 
 This project follows [Google's Open Source Community

ci/check_all_toolchains_tested.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Check whether the set of toolchains tested in this file (other than
+# 'msrv', 'stable', and 'nightly') is equal to the set of toolchains
+# listed in the 'package.metadata.build-rs' section of Cargo.toml.
+#
+# If the inputs to `diff` are not identical, `diff` exits with a
+# non-zero error code, which causes this script to fail (thanks to
+# `set -e`).
+diff \
+  <(cat .github/workflows/ci.yml | yq '.jobs.build_test.strategy.matrix.toolchain | .[]' | \
+    sort -u | grep -v '^\(msrv\|stable\|nightly\)$') \
+  <(cargo metadata --format-version 1 | \
+    jq -r ".packages[] | select(.name == \"zerocopy\").metadata.\"build-rs\" | keys | .[]" | \
+    sort -u)

ci/check_fmt.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+set -eo pipefail
+files=$(find . -iname '*.rs' -type f -not -path './target/*')
+# check that find succeeded
+if [[ -z $files ]]
+then
+	exit 1
+fi
+rustfmt --check $files

ci/check_job_dependencies.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+set -eo pipefail
+which yq > /dev/null
+jobs=$(for i in $(find .github -iname '*.yaml' -or -iname '*.yml')
+  do
+    # Select jobs that are triggered by pull request.
+    if yq -e '.on | has("pull_request")' "$i" 2>/dev/null >/dev/null
+    then
+      # This gets the list of jobs that all-jobs-succeed does not depend on.
+      comm -23 \
+        <(yq -r '.jobs | keys | .[]' "$i" | sort | uniq) \
+        <(yq -r '.jobs.all-jobs-succeed.needs[]' "$i" | sort | uniq)
+    fi
+
+  # The grep call here excludes all-jobs-succeed from the list of jobs that
+  # all-jobs-succeed does not depend on.  If all-jobs-succeed does
+  # not depend on itself, we do not care about it.
+  done | sort | uniq | (grep -v '^all-jobs-succeed$' || true)
+)
+
+if [ -n "$jobs" ]
+then
+  missing_jobs="$(echo "$jobs" | tr ' ' '\n')"
+  echo "all-jobs-succeed missing dependencies on some jobs: $missing_jobs" | tee -a $GITHUB_STEP_SUMMARY
+  exit 1
+fi

ci/check_msrv.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Usage: msrv <crate-name>
+function msrv {
+  cargo metadata --format-version 1 | jq -r ".packages[] | select(.name == \"$1\").rust_version"
+}
+
+ver_zerocopy=$(msrv zerocopy)
+ver_zerocopy_derive=$(msrv zerocopy-derive)
+
+if [[ "$ver_zerocopy" == "$ver_zerocopy_derive" ]]; then
+  echo "Same MSRV ($ver_zerocopy) found for zerocopy and zerocopy-derive." | tee -a $GITHUB_STEP_SUMMARY
+  exit 0
+else
+  echo "Different MSRVs found for zerocopy ($ver_zerocopy) and zerocopy-derive ($ver_zerocopy_derive)." \
+    | tee -a $GITHUB_STEP_SUMMARY >&2
+  exit 1
+fi

ci/check_readme.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Install again in case the installation failed during the
+# `generate_cache` step. We treat that step as best-effort and
+# suppress all errors from it.
+cargo install cargo-readme --version 3.2.0 -q
+
+diff <(./generate-readme.sh) README.md
+exit $?

ci/check_versions.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+# Usage: version <crate-name>
+function version {
+  cargo metadata --format-version 1 | jq -r ".packages[] | select(.name == \"$1\").version"
+}
+
+ver_zerocopy=$(version zerocopy)
+ver_zerocopy_derive=$(version zerocopy-derive)
+
+# Usage: dependency-version <kind> <target>
+function dependency-version {
+  KIND="$1"
+  TARGET="$2"
+  cargo metadata --format-version 1 \
+    | jq -r ".packages[] | select(.name == \"zerocopy\").dependencies[] | select((.name == \"zerocopy-derive\") and .kind == $KIND and .target == $TARGET).req"
+}
+
+# The non-dev dependency version (kind `null` filters out the dev
+# dependency, and target `null` filters out the targeted version).
+zerocopy_derive_dep_ver=$(dependency-version null null)
+
+# The non-dev dependency, targeted version (kind `null` filters out
+# the dev dependency).
+zerocopy_derive_targeted_ver=$(dependency-version null '"cfg(any())"')
+
+# The dev dependency version (kind `"dev"` selects only the dev
+# dependency).
+zerocopy_derive_dev_dep_ver=$(dependency-version '"dev"' null)
+
+function assert-match {
+  VER_A="$1"
+  VER_B="$2"
+  SUCCESS_MSG="$3"
+  FAILURE_MSG="$4"
+  if [[ "$VER_A" == "$VER_B" ]]; then
+    echo "$SUCCESS_MSG" | tee -a $GITHUB_STEP_SUMMARY
+  else
+    echo "$FAILURE_MSG" | tee -a $GITHUB_STEP_SUMMARY >&2
+    exit 1
+  fi
+}
+
+assert-match "$ver_zerocopy" "$ver_zerocopy_derive" \
+  "Same crate version ($ver_zerocopy) found for zerocopy and zerocopy-derive." \
+  "Different crate versions found for zerocopy ($ver_zerocopy) and zerocopy-derive ($ver_zerocopy_derive)."
+
+# Note the leading `=` sign - the dependency needs to be an exact one.
+assert-match "=$ver_zerocopy_derive" "$zerocopy_derive_dep_ver" \
+  "zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dep_ver)." \
+  "zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dep_ver) than the one in-tree ($ver_zerocopy_derive)."
+
+# Note the leading `=` sign - the dependency needs to be an exact one.
+assert-match "=$ver_zerocopy_derive" "$zerocopy_derive_dev_dep_ver" \
+  "In dev mode, zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dev_dep_ver)." \
+  "In dev mode, zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dev_dep_ver) than the one in-tree ($ver_zerocopy_derive)."
+
+assert-match "$zerocopy_derive_dep_ver" "$zerocopy_derive_targeted_ver" \
+  "Same crate version ($zerocopy_derive_dep_ver) found for optional and targeted zerocopy-derive dependency." \
+  "Different crate versions found for optional ($zerocopy_derive_dep_ver) and targeted ($zerocopy_derive_targeted_ver) dependency."

githooks/pre-push

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -eo pipefail
+echo "Running pre-push git hook: $0"
+# forego redirecting stdout to /dev/null on check_fmt.sh because the output
+# from cargofmt is useful (and the good stuff is not delivered by stderr)
+./ci/check_fmt.sh
+./ci/check_job_dependencies.sh > /dev/null
+./ci/check_msrv.sh > /dev/null
+./ci/check_readme.sh > /dev/null
+./ci/check_versions.sh > /dev/null