fix: issue found by fuzzing (#846)

* Add the beginnings of a fuzzing system for CLI11.  This commit adds the fuzzing code, a simple test, and two fixes to issues(seg faults) found by the initial round of fuzzing.  It also adds a few tests and coverage issues uncovered in the process of developing the fuzz tests. As a side effect adjusts some of the azure tests to specify the vmImage which was being changed on azure.

* update license to match rest of code base

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

.github/codecov.yml

@@ -1,6 +1,6 @@
 codecov:
   notify:
-    after_n_builds: 4
+    after_n_builds: 8
 coverage:
   status:
     project:

.github/workflows/fuzz.yml

@@ -0,0 +1,54 @@
+name: Fuzz
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - main
+      - v*
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  quick_fuzz1:
+    name: quickfuzz1
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Configure
+        run: |
+          cmake -S . -B build \
+            -DCMAKE_CXX_STANDARD=17 \
+            -DCLI11_SINGLE_FILE_TESTS=OFF \
+            -DCLI11_BUILD_EXAMPLES=OFF \
+            -DCLI11_FUZZ_TARGET=ON \
+            -DCLI11_BUILD_TESTS=OFF \
+            -DCLI11_BUILD_DOCS=OFF \
+            -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_CXX_COMPILER_FORCED=ON \
+            -DCMAKE_CXX_FLAGS="-g -O1 -fsanitize=fuzzer,undefined,address"
+
+      - name: Build
+        run: cmake --build build -j4
+
+      - name: Test
+        run: |
+          cd build
+          make QUICK_CLI11_APP_FUZZ
+
+      - name: Test2
+        run: |
+          cd build
+          make QUICK_CLI11_FILE_FUZZ
+
+
+      - name: artifacts
+        if: failure()
+        uses: actions/upload-artifact@v3
+        with:
+          name: file_failure
+          path: ./build/fuzz/cli11_*_fail_artifact.txt

.github/workflows/tests.yml

@@ -48,7 +48,7 @@ jobs:
       - name: Prepare coverage
         run: |
           lcov --directory . --capture --output-file coverage.info
-          lcov --remove coverage.info '*/tests/*' '*/examples/*' '/usr/*' '*/book/*' --output-file coverage.info
+          lcov --remove coverage.info '*/tests/*' '*/examples/*' '/usr/*' '*/book/*' '*/fuzz/*' --output-file coverage.info
           lcov --list coverage.info
         working-directory: build