ci: add a debug Tarantool build

The patch adds a Tarantool debug build from the last commit of the
master branch to GitHub Actions workflow. It uses an official build
instruction for Tarantool [1] and the cache action [2] to cache build
outputs.

1. https://www.tarantool.io/ru/doc/latest/dev_guide/building_from_source/
2. https://github.com/actions/cache

Closes #102

Author: oleg-jukovec

.github/workflows/fast_testing.yaml

@@ -25,6 +25,7 @@ jobs:
           - '2.7'
           - '2.8'
           - '2.10'
+          - 'debug-master'
         metrics-version:
           - ''
           - '0.10.0'
@@ -39,10 +40,49 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Install tarantool ${{ matrix.tarantool }}
+        if: startsWith(matrix.tarantool, 'debug') != true
         uses: tarantool/setup-tarantool@v1
         with:
           tarantool-version: ${{ matrix.tarantool }}
 
+      - name: Create version postfix for Tarantool
+        if: startsWith(matrix.tarantool, 'debug')
+        run: |
+          branch=$(echo ${{ matrix.tarantool }} | cut -d- -f2)
+          commit_hash=$(git ls-remote https://github.com/tarantool/tarantool.git --branch ${branch} | head -c 8)
+          echo "version_postfix=-${commit_hash}" >> $GITHUB_ENV
+        shell: bash
+
+      - name: Cache tarantool build
+        if: startsWith(matrix.tarantool, 'debug')
+        id: cache-tnt-debug
+        uses: actions/cache@v3
+        with:
+          path: ~/tnt-debug/
+          key: cache-tnt-${{ matrix.tarantool }}${{ env.version_postfix }}
+
+      - name: Build tarantool ${{ matrix.tarantool }}
+        if: startsWith(matrix.tarantool, 'debug') && steps.cache-tnt-debug.outputs.cache-hit != 'true'
+        run: |
+          sudo apt-get -y install git build-essential cmake make zlib1g-dev \
+            libreadline-dev libncurses5-dev libssl-dev \
+            libunwind-dev libicu-dev python3 python3-yaml \
+            python3-six python3-gevent
+          branch=$(echo ${{ matrix.tarantool }} | cut -d- -f2)
+          git clone --branch ${branch} --single-branch --recursive \
+            https://github.com/tarantool/tarantool.git
+          cd tarantool
+          git submodule update --init --recursive
+          mkdir build && cd build
+          cmake .. -DCMAKE_BUILD_TYPE=Debug -DENABLE_DIST=ON
+          make
+          make DESTDIR=~/tnt-debug/ install
+
+      - name: Install tarantool ${{ matrix.tarantool }}
+        if: startsWith(matrix.tarantool, 'debug')
+        run: |
+          sudo cp -rvP ~/tnt-debug/* /usr/local/
+
       - name: Clone the module
         uses: actions/checkout@v2
 
@@ -51,7 +91,7 @@ jobs:
         id: cache-rocks
         with:
           path: .rocks/
-          key: cache-rocks-${{ matrix.tarantool }}-${{ matrix.metrics-version }}-01
+          key: cache-rocks-${{ matrix.tarantool }}${{ env.version_postfix }}-${{ matrix.metrics-version }}
 
       - name: Install requirements
         run: make deps