add coverage report generation in CI

adds the coverage report generation in CI . Also make the coverage script more CI
friendly.

Author: Prabhat1308

ci/ci-tests.sh

@@ -158,3 +158,28 @@ RUSTFLAGS="--cfg=async_payments" cargo test --verbose --color always -p lightnin
 RUSTFLAGS="--cfg=simple_close" cargo test --verbose --color always -p lightning
 [ "$CI_MINIMIZE_DISK_USAGE" != "" ] && cargo clean
 RUSTFLAGS="--cfg=lsps1_service" cargo test --verbose --color always -p lightning-liquidity
+
+# Generate fuzz coverage report
+echo -e "\n\nGenerating fuzz coverage report"
+if [ -n "$CI" ]; then
+    # In CI, store coverage in a specific directory for artifact collection
+    COVERAGE_DIR="coverage-report"
+    mkdir -p "$COVERAGE_DIR"
+    echo "Installing cargo-llvm-cov..."
+    # Install cargo-llvm-cov if not already installed
+    cargo install cargo-llvm-cov --locked
+    echo "Running fuzz coverage generation..."
+    ./contrib/generate_fuzz_coverage.sh --output-dir "$COVERAGE_DIR"
+    echo "Coverage generation completed. Checking results..."
+    if [ -f "fuzz/$COVERAGE_DIR/html/index.html" ]; then
+        echo "✓ Coverage report successfully generated at fuzz/$COVERAGE_DIR/html/index.html"
+        ls -la "fuzz/$COVERAGE_DIR/html/"
+    else
+        echo "✗ Coverage report not found at expected location"
+        echo "Checking what was created in fuzz/$COVERAGE_DIR:"
+        ls -la "fuzz/$COVERAGE_DIR" || echo "Directory does not exist"
+    fi
+else
+    # Local development
+    ./contrib/generate_fuzz_coverage.sh
+fi

contrib/generate_fuzz_coverage.sh

@@ -2,6 +2,22 @@
 set -e
 set -x
 
+# Parse command line arguments
+OUTPUT_DIR="target/llvm-cov/html"
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        --output-dir)
+            OUTPUT_DIR="$2"
+            shift 2
+            ;;
+        *)
+            echo "Unknown option: $1"
+            echo "Usage: $0 [--output-dir OUTPUT_DIRECTORY]"
+            exit 1
+            ;;
+    esac
+done
+
 # Check if we're in the root directory, if so change to fuzz
 if [ -d "fuzz" ]; then
     cd fuzz
@@ -32,11 +48,28 @@ if [ "$show_corpus_message" = true ]; then
     echo ""
 fi
 
+# Create output directory if it doesn't exist
+mkdir -p "$OUTPUT_DIR"
+
 export RUSTFLAGS="--cfg=fuzzing --cfg=secp256k1_fuzz --cfg=hashes_fuzz"
 # ignore anything in fuzz directory since we don't want coverage of targets 
-cargo llvm-cov --html --ignore-filename-regex "fuzz/"
+cargo llvm-cov --html --ignore-filename-regex "fuzz/" --output-dir "$OUTPUT_DIR"
+
+# Check if coverage report was generated successfully
+# The report is generated directly in $OUTPUT_DIR/html/index.html
+if [ ! -f "$OUTPUT_DIR/html/index.html" ]; then
+    echo "Error: Failed to generate coverage report at $OUTPUT_DIR/html/index.html"
+    # Debug: list what was actually created
+    echo "Contents of $OUTPUT_DIR:"
+    ls -la "$OUTPUT_DIR" || echo "Directory $OUTPUT_DIR does not exist"
+    if [ -d "$OUTPUT_DIR/html" ]; then
+        echo "Contents of $OUTPUT_DIR/html:"
+        ls -la "$OUTPUT_DIR/html"
+    fi
+    exit 1
+fi
 
 echo ""
-echo "Coverage report generated in target/llvm-cov/html/index.html"
+echo "Coverage report generated in $OUTPUT_DIR/html/index.html"