Add CI check to ensure that rustdoc JSON FORMAT_VERSION is correctly updated

Author: GuillaumeGomez

src/ci/docker/host-x86_64/mingw-check-1/Dockerfile

@@ -40,6 +40,7 @@ RUN pip3 install --no-deps --no-cache-dir --require-hashes -r /tmp/reuse-require
 COPY host-x86_64/mingw-check-1/check-default-config-profiles.sh /scripts/
 COPY host-x86_64/mingw-check-1/validate-toolstate.sh /scripts/
 COPY host-x86_64/mingw-check-1/validate-error-codes.sh /scripts/
+COPY host-x86_64/mingw-check-1/validate-rustdoc-json-format-version-update.sh /scripts/
 
 # Check library crates on all tier 1 targets.
 # We disable optimized compiler built-ins because that requires a C toolchain for the target.
@@ -53,6 +54,7 @@ ENV SCRIPT \
            python3 ../x.py check --stage 1 --set build.optimized-compiler-builtins=false core alloc std --target=aarch64-unknown-linux-gnu,i686-pc-windows-msvc,i686-unknown-linux-gnu,x86_64-apple-darwin,x86_64-pc-windows-gnu,x86_64-pc-windows-msvc && \
            /scripts/validate-toolstate.sh && \
            /scripts/validate-error-codes.sh && \
+           /scripts/validate-rustdoc-json-format-version-update.sh && \
            reuse --include-submodules lint && \
            python3 ../x.py test collect-license-metadata && \
            # Runs checks to ensure that there are no issues in our JS code.

src/ci/docker/host-x86_64/mingw-check-1/validate-rustdoc-json-format-version-update.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+# Checks that the rustdoc-json-types `FORMAT_VERSION` was updated correctly.
+
+set -eo pipefail
+
+if [[ -z "$BASE_COMMIT" ]]; then
+    echo "not checking error code explanations removal"
+    exit 0
+fi
+
+echo 'Check if rustdoc JSON `FORMAT_VERSION` was correctly updated...'
+
+if (git diff "$BASE_COMMIT" --name-status | grep '^M' \
+        | grep --quiet "src/rustdoc-json-types"); then
+    # FIXME: Also check that `FORMAT_VERSION` is increased if any code change occurred
+    if (git diff "$BASE_COMMIT" src/rustdoc-json-types \
+	    | grep --quiet "+pub const FORMAT_VERSION: u32 =") && !(
+	       git diff "$BASE_COMMIT" | grep --quiet "+// Latest feature:"); then
+	echo '`FORMAT_VERSION` was updated, but the `Latest feature` comment was not'
+        exit 1
+    fi
+fi
+
+echo 'No problem with rustdoc JSON `FORMAT_VERSION` update'

src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile

@@ -40,6 +40,7 @@ RUN pip3 install --no-deps --no-cache-dir --require-hashes -r /tmp/reuse-require
 
 COPY host-x86_64/mingw-check-1/validate-toolstate.sh /scripts/
 COPY host-x86_64/mingw-check-1/validate-error-codes.sh /scripts/
+COPY host-x86_64/mingw-check-1/validate-rustdoc-json-format-version-update.sh /scripts/
 
 RUN bash -c 'npm install -g eslint@$(cat /tmp/eslint.version)'