Ensure enforce.sh doesn't use unset variables

Test this by using `set -u` in build scripts

Author: Flamefire

ci/build.sh

@@ -1,20 +1,21 @@
 #!/bin/bash
 #
 # Copyright 2017 - 2022 James E. King III
+# Copyright 2020 - 2025 Alexander Grund
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at
 #      http://www.boost.org/LICENSE_1_0.txt)
 #
 # Bash script to perform a bjam build
 #
 
-set -ex
+set -eux
 
 : "${B2_TARGETS:="libs/$SELF/test"}"
 
 . "$(dirname "${BASH_SOURCE[0]}")"/enforce.sh
 
-export UBSAN_OPTIONS=print_stacktrace=1,report_error_type=1,${UBSAN_OPTIONS}
+export UBSAN_OPTIONS=print_stacktrace=1,report_error_type=1,${UBSAN_OPTIONS:-}
 
 cd "$BOOST_ROOT"
 
@@ -33,9 +34,9 @@ if [[ -f "$b2_config" ]]; then
 fi
 
 # shellcheck disable=SC2086
-${B2_WRAPPER} ./b2 ${B2_TARGETS} "${B2_ARGS[@]}" "$@"
+${B2_WRAPPER:-} ./b2 ${B2_TARGETS} "${B2_ARGS[@]}" "$@"
 
-if [ "$B2_USE_CCACHE" == "1" ] && command -v ccache &> /dev/null; then
+if [ "${B2_USE_CCACHE:-0}" == "1" ] && command -v ccache &> /dev/null; then
   echo "CCache summary"
   ccache -s
 fi

ci/codecov.sh

@@ -23,14 +23,14 @@
 # a pull request.
 #
 
-set -ex
+set -eux
 
 . "$(dirname "${BASH_SOURCE[0]}")"/enforce.sh
 
-coverage_action=$1
+coverage_action=${1:-'<unset>'}
 
 if [[ "$coverage_action" == "setup" ]]; then
-    if [ -z "$B2_CI_VERSION" ]; then
+    if [ -z "${B2_CI_VERSION:-}" ]; then
         # Old CI version needs to use the prefixes
         export B2_VARIANT="variant=debug"
         export B2_CXXFLAGS="${B2_CXXFLAGS:+$B2_CXXFLAGS }cxxflags=-fkeep-static-functions cxxflags=--coverage"
@@ -42,7 +42,7 @@ if [[ "$coverage_action" == "setup" ]]; then
     fi
 
 elif [[ "$coverage_action" == "collect" ]] || [[ "$coverage_action" == "upload" ]]; then
-    if [ -z "$GCOV" ]; then
+    if [ -z "${GCOV:-}" ]; then
         ver=7 # default
         if [ "${B2_TOOLSET%%-*}" == "gcc" ]; then
             if [[ "$B2_TOOLSET" =~ gcc- ]]; then
@@ -55,6 +55,7 @@ elif [[ "$coverage_action" == "collect" ]] || [[ "$coverage_action" == "upload"
     fi
 
     : "${LCOV_VERSION:=v2.3}" # Set default lcov version to install
+    : "${LCOV_OPTIONS:=}"
 
     : "${LCOV_BRANCH_COVERAGE:=1}" # Set default for branch coverage
 
@@ -136,7 +137,7 @@ elif [[ "$coverage_action" == "collect" ]] || [[ "$coverage_action" == "upload"
     # pull request)
     lcov ${LCOV_OPTIONS} --list coverage.info
 
-    if [[ "$coverage_action" == "upload" ]] && [[ "$BOOST_CI_CODECOV_IO_UPLOAD" != "skip" ]]; then
+    if [[ "$coverage_action" == "upload" ]] && [[ "${BOOST_CI_CODECOV_IO_UPLOAD:-}" != "skip" ]]; then
         #
         # upload to codecov.io
         #

ci/common_install.sh

@@ -35,7 +35,7 @@ function print_on_gha {
 }
 
 # Setup ccache
-if [ "$B2_USE_CCACHE" == "1" ]; then
+if [ "${B2_USE_CCACHE:-}" == "1" ]; then
     if ! "$CI_DIR"/setup_ccache.sh 2>&1; then
         { set +x; } &> /dev/null
         echo
@@ -59,7 +59,7 @@ print_on_gha "::endgroup::"
 print_on_gha "::group::Checkout and setup Boost build tree"
 pythonexecutable=$(get_python_executable)
 
-if [ -z "$SELF" ]; then
+if [ -z "${SELF:-}" ]; then
     export SELF=$($pythonexecutable "$CI_DIR/get_libname.py")
 fi
 
@@ -92,6 +92,7 @@ cp -r "$BOOST_CI_SRC_FOLDER"/* "libs/$SELF"
 export BOOST_ROOT="$(pwd)"
 export PATH="$(pwd):$PATH"
 
+git --version
 DEPINST_ARGS=()
 if [[ -n "$GIT_FETCH_JOBS" ]]; then
     DEPINST_ARGS+=("--git_args" "--jobs $GIT_FETCH_JOBS")
@@ -103,7 +104,7 @@ print_on_gha "::endgroup::"
 
 print_on_gha "::group::Setup B2"
 # Deduce B2_TOOLSET if unset from B2_COMPILER
-if [ -z "$B2_TOOLSET" ] && [ -n "$B2_COMPILER" ]; then
+if [ -z "${B2_TOOLSET:-}" ] && [ -n "${B2_COMPILER:-}" ]; then
     if [[ "$B2_COMPILER" =~ clang ]]; then
         export B2_TOOLSET=clang
     elif [[ "$B2_COMPILER" =~ gcc|g\+\+ ]]; then
@@ -114,7 +115,7 @@ if [ -z "$B2_TOOLSET" ] && [ -n "$B2_COMPILER" ]; then
     fi
 fi
 
-if [[ "$B2_TOOLSET" == clang* ]]; then
+if [[ "${B2_TOOLSET:-}" == clang* ]]; then
     # If clang was installed from LLVM APT it will not have a /usr/bin/clang++
     # so we need to add the correctly versioned llvm bin path to the PATH
     if [ -f "/etc/debian_version" ]; then
@@ -134,7 +135,7 @@ if [[ "$B2_TOOLSET" == clang* ]]; then
             ls -ls "/usr/lib/llvm-${ver}/bin" || true
             hash -r || true
         fi
-    elif [ -n "${XCODE_APP}" ]; then
+    elif [ -n "${XCODE_APP:-}" ]; then
         sudo xcode-select -switch "${XCODE_APP}"
     fi
     command -v clang || true
@@ -152,7 +153,7 @@ fi
 
 # Set up user-config to actually use B2_COMPILER if set
 userConfigPath=$HOME/user-config.jam
-if [ -n "$B2_COMPILER" ]; then
+if [ -n "${B2_COMPILER:-}" ]; then
     echo '$B2_COMPILER set. Configuring user-config'
 
     # Get C++ compiler
@@ -212,13 +213,13 @@ function show_bootstrap_log
 }
 print_on_gha "::endgroup::"
 
-if [[ "$B2_DONT_BOOTSTRAP" != "1" ]]; then
+if [[ "${B2_DONT_BOOTSTRAP:0}" != "1" ]]; then
     print_on_gha "::group::Bootstrap B2"
     trap show_bootstrap_log ERR
     # Check if b2 already exists. This would (only) happen in a caching scenario. The purpose of caching is to save time by not recompiling everything.
     # The user may clear cache or delete b2 beforehand if they wish to rebuild.
     if [ ! -f b2 ] || ! b2_version_output=$(./b2 --version); then
-        ${B2_WRAPPER} ./bootstrap.sh
+        ${B2_WRAPPER:-} ./bootstrap.sh
     else
         # b2 expects versions to match
         engineversion=$(echo "$b2_version_output" | tr -s ' ' | cut -d' ' -f2 | cut -d'-' -f1)
@@ -229,10 +230,10 @@ if [[ "$B2_DONT_BOOTSTRAP" != "1" ]]; then
         if [[ "${enginemajorversion}" == "${coremajorversion}" ]] && [[ "${engineminorversion}" == "${coreminorversion}" ]]; then
             echo "b2 already exists and has the same version number"
         else
-            ${B2_WRAPPER} ./bootstrap.sh
+            ${B2_WRAPPER:-} ./bootstrap.sh
         fi
     fi
     trap - ERR
-    ${B2_WRAPPER} ./b2 -d0 headers
+    ${B2_WRAPPER:-} ./b2 -d0 headers
     print_on_gha "::endgroup::"
 fi

ci/enforce.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 #
 # Copyright 2017 - 2019 James E. King III
-# Copyright 2020 - 2024 Alexander Grund
+# Copyright 2020 - 2025 Alexander Grund
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at
 #      http://www.boost.org/LICENSE_1_0.txt)
@@ -27,17 +27,17 @@ function enforce_b2 {
     local old_varname=$1
     local new_varname=B2_${old_varname}
 
-    if [ -z "${!new_varname}" ]; then
-        if [ -n "${!old_varname}" ]; then
+    if [ -z "${!new_varname:-}" ]; then
+        if [ -n "${!old_varname:-}" ]; then
             if [ "$TRAVIS" = "true" ]; then
                 local ci_script=".travis.yml"
-            elif [ -n "${GITHUB_WORKFLOW}" ]; then
+            elif [ -n "${GITHUB_WORKFLOW:-}" ]; then
                 local ci_script="${GITHUB_WORKFLOW} workflow"
-            elif [ -n "$AGENT_OS" ]; then
+            elif [ -n "${AGENT_OS:-}" ]; then
                 local ci_script=".azure-pipelines.yml or azure-pipelines.yml"
             fi
             echo
-            echo "WARNING: Your ${ci_script} file needs to be updated:"
+            echo "WARNING: Your ${ci_script:-CI} file needs to be updated:"
             echo "         use ${new_varname} instead of ${old_varname}"
             echo
             export "${new_varname}"="${!old_varname}"
@@ -54,26 +54,26 @@ enforce_b2 "TESTFLAGS"
 enforce_b2 "TOOLSET"
 
 # default language level: C++11
-if [ -z "$B2_CXXSTD" ]; then
+if [ -z "${B2_CXXSTD:-}" ]; then
     export B2_CXXSTD=11
 fi
 
 # default parallel build jobs: number of CPUs available + 1
-if [ -z "${B2_JOBS}" ]; then
+if [ -z "${B2_JOBS:-}" ]; then
     pythonexecutable=$(get_python_executable)
     cpus=$(grep -c 'processor' /proc/cpuinfo || $pythonexecutable -c 'import multiprocessing as mp; print(mp.cpu_count())' || echo "2")
     export B2_JOBS=$((cpus + 1))
 fi
 
 # Build cmdline arguments for B2 in the array B2_ARGS to preserve quotes
 
-if [ -n "$B2_CI_VERSION" ]; then # Set B2_CI_VERSION to opt in to new features
+if [ -n "${B2_CI_VERSION:-}" ]; then # Set B2_CI_VERSION to opt in to new features
   function append_b2_args {
       # Generate multiple "option=value" entries from the value of an environment variable
       # Handles correct splitting and quoting
       local var_name="$1"
       local option_name="$2"
-      if [ -n "${!var_name}" ]; then
+      if [ -n "${!var_name:-}" ]; then
           while IFS= read -r -d '' value; do
               # If the value has an assignment and a space we need to quote it
               if [[ $value == *"="*" "* ]]; then
@@ -96,18 +96,18 @@ if [ -n "$B2_CI_VERSION" ]; then # Set B2_CI_VERSION to opt in to new features
   B2_ARGS=(
       "${B2_ARGS[@]}"
       ${B2_LINKFLAGS:+"linkflags=$B2_LINKFLAGS"}
-      ${B2_TESTFLAGS}
+      ${B2_TESTFLAGS:-}
       ${B2_ADDRESS_MODEL:+address-model=$B2_ADDRESS_MODEL}
       ${B2_LINK:+link=$B2_LINK}
       ${B2_VISIBILITY:+visibility=$B2_VISIBILITY}
       ${B2_STDLIB:+"stdlib=$B2_STDLIB"}
-      ${B2_THREADING}
+      ${B2_THREADING:-}
       ${B2_VARIANT:+variant=$B2_VARIANT}
       ${B2_ASAN:+address-sanitizer=norecover}
       ${B2_TSAN:+thread-sanitizer=norecover}
       ${B2_UBSAN:+undefined-sanitizer=norecover}
       -j"${B2_JOBS}"
-      ${B2_FLAGS}
+      ${B2_FLAGS:-}
   )
 else
   # Legacy codepath for compatibility for for old versions of the .github/*.yml files:
@@ -116,15 +116,15 @@ else
   B2_ARGS=(
       toolset="$B2_TOOLSET"
       cxxstd="$B2_CXXSTD"
-      $B2_CXXFLAGS
-      $B2_DEFINES
-      $B2_INCLUDE
-      $B2_LINKFLAGS
-      $B2_TESTFLAGS
-      $B2_ADDRESS_MODEL
-      $B2_LINK
-      $B2_THREADING
-      $B2_VARIANT
+      ${B2_CXXFLAGS:-}
+      ${B2_DEFINES:-}
+      ${B2_INCLUDE:-}
+      ${B2_LINKFLAGS:-}
+      ${B2_TESTFLAGS:-}
+      ${B2_ADDRESS_MODEL:-}
+      ${B2_LINK:-}
+      ${B2_THREADING:-}
+      ${B2_VARIANT:-}
       -j"${B2_JOBS}"
   )
 fi

ci/travis/codecov.sh

@@ -9,7 +9,7 @@
 # Bash script to run in travis to perform codecov.io integration
 #
 
-set -ex
+set -eux
 
 CI_DIR="$(dirname "${BASH_SOURCE[0]}")/.."