Revert hybrid install, handle inexact version

Author: dkaszews

action.yml

@@ -7,7 +7,7 @@ branding:
 
 inputs:
   clang-format-version:
-    description: 'The major version of clang-format that you want to use.'
+    description: 'The version of clang-format that you want to use. Use either major version, or exact one.'
     required: false
     default: '21'
   check-path:

check.sh

@@ -56,7 +56,7 @@ format_diff() {
 }
 
 CLANG_FORMAT_VERSION="$1"
-CLANG_FORMAT_MAJOR_VERSION=${CLANG_FORMAT_VERSION%%.*}
+CLANG_FORMAT_MAJOR_VERSION="${CLANG_FORMAT_VERSION%%.*}"
 CHECK_PATH="$2"
 FALLBACK_STYLE="$3"
 EXCLUDE_REGEX="$4"

clang-format-docker/Dockerfile

@@ -2,21 +2,20 @@ ARG UBUNTU_VERSION
 FROM ubuntu:${UBUNTU_VERSION}
 
 ARG CLANG_FORMAT_VERSION
-ENV CLANG_FORMAT_MAJOR_VERSION=${CLANG_FORMAT_VERSION%%.*}
+ENV PIP_ROOT_USER_ACTION=ignore
+ENV PIP_BREAK_SYSTEM_PACKAGES=1
 
 RUN apt-get update \
-	&& apt-get install --no-install-recommends -y \
-	clang-format-${CLANG_FORMAT_MAJOR_VERSION} \
-	&& mv /usr/bin/clang-format-${CLANG_FORMAT_MAJOR_VERSION} /usr/bin/clang-format
-
-RUN [ $CLANG_FORMAT_VERSION != $CLANG_FORMAT_MAJOR_VERSION ] \
-	&& apt-get install --no-install-recommends -y python-pip \
-	&& pip install "clang-format~=$CLANG_FORMAT_VERSION" \
-	&& mv -f "$(which clang-format)" /usr/bin/clang-format
-
-# Clean cache
-RUN apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false \
-	&& apt-get clean -y && rm -rf /var/lib/apt/lists/*
+	&& apt-get install --no-install-recommends -y python3-pip \
+	&& pip install -v "$( \
+		echo "$CLANG_FORMAT_VERSION" | grep -qF '.' \
+		&& echo "clang-format==${CLANG_FORMAT_VERSION}" \
+		|| echo "clang-format==${CLANG_FORMAT_VERSION}.*" \
+	)" \
+	# Clean cache
+	&& apt-get purge -y --auto-remove -o APT::AutoRemove::RecommendsImportant=false \
+	&& apt-get clean -y && rm -rf /var/lib/apt/lists/* \
+	&& mv /usr/local/bin/clang-format /usr/bin/clang-format
 
 WORKDIR /