Merge pull request #72347 from NixOS/bash-no-undef-vars

treewide: `set -u` everywhere
2019-11-04 19:52:33 -05:00
parent 0a9e548b2f c5cf009996
commit acd2d19484
65 changed files with 95 additions and 134 deletions
@@ -125,6 +125,13 @@
      <link linkend="opt-networking.interfaces">networking.interfaces.&lt;name&gt;.…</link> options.
    </para>
   </listitem>
+   <listitem>
+    <para>
+      The stdenv now runs all bash with <literal>set -u</literal>, to catch the use of undefined variables.
+      Before, it itself used <literal>set -u</literal> but was careful to unset it so other packages' code ran as before.
+      Now, all bash code is held to the same high standard, and the rather complex stateful manipulation of the options can be discarded.
+    </para>
+   </listitem>
  </itemizedlist>
 </section>

@@ -111,17 +111,13 @@ stdenv.mkDerivation {

  installPhase =
    ''
-      set -u
-
      mkdir -p $out/bin $out/nix-support

      wrap() {
        local dst="$1"
        local wrapper="$2"
        export prog="$3"
-        set +u
        substituteAll "$wrapper" "$out/bin/$dst"
-        set -u
        chmod +x "$out/bin/$dst"
      }
    ''
@@ -163,8 +159,6 @@ stdenv.mkDerivation {
        [[ -e "$underlying" ]] || continue
        wrap ${targetPrefix}$variant ${./ld-wrapper.sh} $underlying
      done
-
-      set +u
    '';

  emulation = let
@@ -307,7 +301,6 @@ stdenv.mkDerivation {
    ''

    + ''
-      set +u
      substituteAll ${./add-flags.sh} $out/nix-support/add-flags.sh
      substituteAll ${./add-hardening.sh} $out/nix-support/add-hardening.sh
      substituteAll ${../wrapper-common/utils.bash} $out/nix-support/utils.bash
@@ -29,9 +29,9 @@ attrsOrig @
      configurePhase = ''
        runHook preConfigure

-        [ -z "$dontPlacateNuget" ] && placate-nuget.sh
-        [ -z "$dontPlacatePaket" ] && placate-paket.sh
-        [ -z "$dontPatchFSharpTargets" ] && patch-fsharp-targets.sh
+        [ -z "''${dontPlacateNuget-}" ] && placate-nuget.sh
+        [ -z "''${dontPlacatePaket-}" ] && placate-paket.sh
+        [ -z "''${dontPatchFSharpTargets-}" ] && patch-fsharp-targets.sh

        runHook postConfigure
      '';
@@ -69,7 +69,7 @@ attrsOrig @

        cp -rv ${arrayToShell outputFiles} "''${outputFilesArray[@]}" "$target"

-        if [ -z "$dontRemoveDuplicatedDlls" ]
+        if [ -z "''${dontRemoveDuplicatedDlls-}" ]
        then
          pushd "$out"
          remove-duplicated-dlls.sh
@@ -7,7 +7,7 @@
 # the moment that would produce too many spurious errors (e.g. debug
 # info or assertion messages that refer to $TMPDIR).

-fixupOutputHooks+=('if [ -z "$noAuditTmpdir" -a -e "$prefix" ]; then auditTmpdir "$prefix"; fi')
+fixupOutputHooks+=('if [[ -z "${noAuditTmpdir-}" && -e "$prefix" ]]; then auditTmpdir "$prefix"; fi')

 auditTmpdir() {
    local dir="$1"
@@ -228,7 +228,7 @@ autoPatchelf() {
 # behaviour as fixupOutputHooks because the setup hook for patchelf is run in
 # fixupOutput and the postFixup hook runs later.
 postFixupHooks+=('
-    if [ -z "$dontAutoPatchelf" ]; then
+    if [ -z "${dontAutoPatchelf-}" ]; then
        autoPatchelf -- $(for output in $outputs; do
            [ -e "${!output}" ] || continue
            echo "${!output}"
@@ -1,4 +1,4 @@
-fixupOutputHooks+=('if [ -z "$dontGzipMan" ]; then compressManPages "$prefix"; fi')
+fixupOutputHooks+=('if [ -z "${dontGzipMan-}" ]; then compressManPages "$prefix"; fi')

 compressManPages() {
    local dir="$1"
@@ -11,12 +11,12 @@ addXMLCatalogs () {
    done
 }

-if [ -z "$libxmlHookDone" ]; then
+if [ -z "${libxmlHookDone-}" ]; then
    libxmlHookDone=1

    # Set up XML_CATALOG_FILES.  An empty initial value prevents
    # xmllint and xsltproc from looking in /etc/xml/catalog.
-    export XML_CATALOG_FILES
+    export XML_CATALOG_FILES=''
    if [ -z "$XML_CATALOG_FILES" ]; then XML_CATALOG_FILES=" "; fi
    addEnvHooks "$hostOffset" addXMLCatalogs
 fi
@@ -8,7 +8,7 @@
 fixupOutputHooks+=(_moveLib64)

 _moveLib64() {
-    if [ "$dontMoveLib64" = 1 ]; then return; fi
+    if [ "${dontMoveLib64-}" = 1 ]; then return; fi
    if [ ! -e "$prefix/lib64" -o -L "$prefix/lib64" ]; then return; fi
    echo "moving $prefix/lib64/* to $prefix/lib"
    mkdir -p $prefix/lib
@@ -5,7 +5,7 @@
 fixupOutputHooks+=(_moveSbin)

 _moveSbin() {
-    if [ "$dontMoveSbin" = 1 ]; then return; fi
+    if [ "${dontMoveSbin-}" = 1 ]; then return; fi
    if [ ! -e "$prefix/sbin" -o -L "$prefix/sbin" ]; then return; fi
    echo "moving $prefix/sbin/* to $prefix/bin"
    mkdir -p $prefix/bin
@@ -9,8 +9,8 @@ _assignFirst() {
    local varName="$1"
    local REMOVE=REMOVE # slightly hacky - we allow REMOVE (i.e. not a variable name)
    shift
-    while [ $# -ge 1 ]; do
-        if [ -n "${!1}" ]; then eval "${varName}"="$1"; return; fi
+    while (( $# )); do
+        if [ -n "${!1-}" ]; then eval "${varName}"="$1"; return; fi
        shift
    done
    echo "Error: _assignFirst found no valid variant!"
@@ -19,7 +19,7 @@ _assignFirst() {

 # Same as _assignFirst, but only if "$1" = ""
 _overrideFirst() {
-    if [ -z "${!1}" ]; then
+    if [ -z "${!1-}" ]; then
        _assignFirst "$@"
    fi
 }
@@ -105,7 +105,7 @@ patchShebangs() {
 }

 patchShebangsAuto () {
-    if [ -z "$dontPatchShebangs" -a -e "$prefix" ]; then
+    if [ -z "${dontPatchShebangs-}" -a -e "$prefix" ]; then

        # Dev output will end up being run on the build platform. An
        # example case of this is sdl2-config. Otherwise, we can just
@@ -8,7 +8,7 @@
 fixupOutputHooks+=(_pruneLibtoolFiles)

 _pruneLibtoolFiles() {
-    if [ "$dontPruneLibtoolFiles" ] || [ ! -e "$prefix" ]; then
+    if [ "${dontPruneLibtoolFiles-}" ] || [ ! -e "$prefix" ]; then
       return
    fi

@@ -10,7 +10,7 @@ _doStrip() {
    local -ra stripCmds=(STRIP TARGET_STRIP)

    # Optimization
-    if [[ "$STRIP" == "$TARGET_STRIP" ]]; then
+    if [[ "${STRIP-}" == "${TARGET_STRIP-}" ]]; then
        dontStripTarget+=1
    fi

@@ -20,7 +20,7 @@ _doStrip() {
        local -n stripCmd="${stripCmds[$i]}"

        # `dontStrip` disables them all
-        if [[ "$dontStrip" || "$flag" ]] || ! type -f "$stripCmd" 2>/dev/null
+        if [[ "${dontStrip-}" || "${flag-}" ]] || ! type -f "${stripCmd-}" 2>/dev/null
        then continue; fi

        stripDebugList=${stripDebugList:-lib lib32 lib64 libexec bin sbin}
@@ -1,7 +1,7 @@
 preConfigurePhases+=" updateAutotoolsGnuConfigScriptsPhase"

 updateAutotoolsGnuConfigScriptsPhase() {
-    if [ -n "$dontUpdateAutotoolsGnuConfigScripts" ]; then return; fi
+    if [ -n "${dontUpdateAutotoolsGnuConfigScripts-}" ]; then return; fi

    for script in config.sub config.guess; do
        for f in $(find . -type f -name "$script"); do
@@ -15,7 +15,7 @@ wrapGApp() {
    wrapProgram "$program" "${gappsWrapperArgs[@]}" "$@"
 }

-# Note: $gappsWrapperArgs still gets defined even if $dontWrapGApps is set.
+# Note: $gappsWrapperArgs still gets defined even if ${dontWrapGApps-} is set.
 wrapGAppsHook() {
  # guard against running multiple times (e.g. due to propagation)
  [ -z "$wrapGAppsHookHasRun" ] || return 0
@@ -37,7 +37,7 @@ let cpuName = stdenv.hostPlatform.parsed.cpu.name;

    # Set JAVA_HOME automatically.
    cat <<EOF >> $out/nix-support/setup-hook
-    if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+    if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
    EOF
  '';

@@ -54,7 +54,7 @@ let result = stdenv.mkDerivation rec {

    # Set JAVA_HOME automatically.
    cat <<EOF >> "$out/nix-support/setup-hook"
-    if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+    if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
    EOF
  '';

@@ -270,7 +270,7 @@ in rec {
      # Set JAVA_HOME automatically.
      mkdir -p $out/nix-support
      cat <<EOF > $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
      EOF
    '';
    postFixup = openjdk.postFixup or null;
@@ -72,7 +72,7 @@ let
      # Set JAVA_HOME automatically.
      mkdir -p $out/nix-support
      cat <<EOF > $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
      EOF
    '';

@@ -106,7 +106,7 @@ let
      # Set JAVA_HOME automatically.
      mkdir -p $out/nix-support
      cat <<EOF > $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out/lib/openjdk; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out/lib/openjdk; fi
      EOF
    '';

@@ -231,7 +231,7 @@ let
      # Set JAVA_HOME automatically.
      mkdir -p $out/nix-support
      cat <<EOF > $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out/lib/openjdk; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out/lib/openjdk; fi
      EOF
    '';

@@ -44,7 +44,7 @@ let

      # Set JAVA_HOME automatically.
      cat <<EOF >> $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
      EOF
    '';

@@ -44,7 +44,7 @@ let

      # Set JAVA_HOME automatically.
      cat <<EOF >> $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
      EOF
    '';

@@ -44,7 +44,7 @@ let

      # Set JAVA_HOME automatically.
      cat <<EOF >> $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
      EOF
    '';

@@ -114,7 +114,7 @@ let
      # Set JAVA_HOME automatically.
      mkdir -p $out/nix-support
      cat <<EOF > $out/nix-support/setup-hook
-      if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out/lib/openjdk; fi
+      if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out/lib/openjdk; fi
      EOF
    '';

@@ -156,7 +156,7 @@ let result = stdenv.mkDerivation rec {

    # Set JAVA_HOME automatically.
    cat <<EOF >> $out/nix-support/setup-hook
-    if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+    if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
    EOF
  '';

@@ -1,4 +1,4 @@
 # Fix 'failed to open: /homeless-shelter/.cargo/.package-cache' in rust 1.36.
-if [[ -z $IN_NIX_SHELL && -z $CARGO_HOME ]]; then
+if [[ -z ${IN_NIX_SHELL-} && -z ${CARGO_HOME-} ]]; then
    export CARGO_HOME=$TMPDIR
 fi
@@ -58,7 +58,7 @@ in stdenv.mkDerivation {

    # Set JAVA_HOME automatically.
    cat <<EOF >> $out/nix-support/setup-hook
-    if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+    if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
    EOF
  '';

@@ -55,7 +55,7 @@ in stdenv.mkDerivation {

    # Set JAVA_HOME automatically.
    cat <<EOF >> $out/nix-support/setup-hook
-    if [ -z "\$JAVA_HOME" ]; then export JAVA_HOME=$out; fi
+    if [ -z "\''${JAVA_HOME-}" ]; then export JAVA_HOME=$out; fi
    EOF
  '';

@@ -9,7 +9,7 @@ flitBuildPhase () {
    echo "Finished executing flitBuildPhase"
 }

-if [ -z "$dontUseFlitBuild" ] && [ -z "$buildPhase" ]; then
+if [ -z "${dontUseFlitBuild-}" ] && [ -z "${buildPhase-}" ]; then
    echo "Using flitBuildPhase"
    buildPhase=flitBuildPhase
 fi
@@ -31,7 +31,7 @@ pipShellHook() {
    echo "Finished executing pipShellHook"
 }

-if [ -z "$dontUsePipBuild" ] && [ -z "$buildPhase" ]; then
+if [ -z "${dontUsePipBuild-}" ] && [ -z "${buildPhase-}" ]; then
    echo "Using pipBuildPhase"
    buildPhase=pipBuildPhase
 fi
@@ -18,7 +18,7 @@ pipInstallPhase() {
    echo "Finished executing pipInstallPhase"
 }

-if [ -z "$dontUsePipInstall" ] && [ -z "$installPhase" ]; then
+if [ -z "${dontUsePipInstall-}" ] && [ -z "${installPhase-}" ]; then
    echo "Using pipInstallPhase"
    installPhase=pipInstallPhase
 fi
@@ -43,7 +43,7 @@ function pytestCheckPhase() {
    echo "Finished executing pytestCheckPhase"
 }

-if [ -z "$dontUsePytestCheck" ] && [ -z "$installCheckPhase" ]; then
+if [ -z "${dontUsePytestCheck-}" ] && [ -z "${installCheckPhase-}" ]; then
    echo "Using pytestCheckPhase"
    preDistPhases+=" pytestCheckPhase"
 fi
@@ -5,6 +5,6 @@ pythonCatchConflictsPhase() {
    @pythonInterpreter@ @catchConflicts@
 }

-if [ -z "$dontUsePythonCatchConflicts" ]; then
+if [ -z "${dontUsePythonCatchConflicts-}" ]; then
    preDistPhases+=" pythonCatchConflictsPhase"
 fi
@@ -10,7 +10,7 @@ pythonImportsCheckPhase () {
    fi
 }

-if [ -z "$dontUsePythonImportsCheck" ]; then
+if [ -z "${dontUsePythonImportsCheck-}" ]; then
    echo "Using pythonImportsCheckPhase"
    preDistPhases+=" pythonImportsCheckPhase"
 fi
@@ -12,6 +12,6 @@ pythonRemoveBinBytecodePhase () {
    fi
 }

-if [ -z "$dontUsePythonRemoveBinBytecode" ]; then
+if [ -z "${dontUsePythonRemoveBinBytecode-}" ]; then
    preDistPhases+=" pythonRemoveBinBytecodePhase"
 fi
@@ -36,12 +36,12 @@ setuptoolsShellHook() {
    echo "Finished executing setuptoolsShellHook"
 }

-if [ -z "$dontUseSetuptoolsBuild" ] && [ -z "$buildPhase" ]; then
+if [ -z "${dontUseSetuptoolsBuild-}" ] && [ -z "${buildPhase-}" ]; then
    echo "Using setuptoolsBuildPhase"
    buildPhase=setuptoolsBuildPhase
 fi

-if [ -z "$dontUseSetuptoolsShellHook" ] && [ -z "$shellHook" ]; then
+if [ -z "${dontUseSetuptoolsShellHook-}" ] && [ -z "${shellHook-}" ]; then
    echo "Using setuptoolsShellHook"
    shellHook=setuptoolsShellHook
 fi
@@ -12,7 +12,7 @@ setuptoolsCheckPhase() {
    echo "Finished executing setuptoolsCheckPhase"
 }

-if [ -z "$dontUseSetuptoolsCheck" ] && [ -z "$installCheckPhase" ]; then
+if [ -z "${dontUseSetuptoolsCheck-}" ] && [ -z "${installCheckPhase-}" ]; then
    echo "Using setuptoolsCheckPhase"
    preDistPhases+=" setuptoolsCheckPhase"
 fi
@@ -12,7 +12,7 @@ wheelUnpackPhase(){
    echo "Finished executing wheelUnpackPhase"
 }

-if [ -z "$dontUseWheelUnpack" ] && [ -z "$unpackPhase" ]; then
+if [ -z "${dontUseWheelUnpack-}" ] && [ -z "${unpackPhase-}" ]; then
    echo "Using wheelUnpackPhase"
    unpackPhase=wheelUnpackPhase
 fi
@@ -10,7 +10,7 @@ addEnvHooks "$hostOffset" gettextDataDirsHook

 # libintl must be listed in load flags on non-Glibc
 # it doesn't hurt to have it in Glibc either though
-if [ -n "@gettextNeedsLdflags@" -a -z "$dontAddExtraLibs" ]; then
+if [ -n "@gettextNeedsLdflags@" -a -z "${dontAddExtraLibs-}" ]; then
    # See pkgs/build-support/setup-hooks/role.bash
    getHostRole
    export NIX_${role_pre}LDFLAGS+=" -lintl"
@@ -16,4 +16,4 @@ dropIconThemeCache() {
    fi
 }

-preFixupPhases="$preFixupPhases dropIconThemeCache"
+preFixupPhases="${preFixupPhases-} dropIconThemeCache"
@@ -2,7 +2,7 @@
 # it doesn't hurt to have it in Glibc either though

 # See pkgs/build-support/setup-hooks/role.bash
-if [ -z "$dontAddExtraLibs" ]; then
+if [ -z "${dontAddExtraLibs-}" ]; then
    getHostRole
    export NIX_${role_pre}LDFLAGS+=" -liconv"
 fi
@@ -31,6 +31,6 @@ qmakeConfigurePhase() {
    runHook postConfigure
 }

-if [ -z "$dontUseQmakeConfigure" -a -z "$configurePhase" ]; then
+if [ -z "${dontUseQmakeConfigure-}" -a -z "${configurePhase-}" ]; then
    configurePhase=qmakeConfigurePhase
 fi
@@ -61,6 +61,6 @@ postPatchMkspecs() {
        fixQtBuiltinPaths "$dev/mkspecs" '*.pr?'
    fi
 }
-if [ -z "$dontPatchMkspecs" ]; then
-    postPhases="${postPhases}${postPhases:+ }postPatchMkspecs"
+if [ -z "${dontPatchMkspecs-}" ]; then
+    postPhases="${postPhases-}${postPhases:+ }postPatchMkspecs"
 fi
@@ -64,10 +64,10 @@ qtOwnPathsHook() {

 preFixupPhases+=" qtOwnPathsHook"

-# Note: $qtWrapperArgs still gets defined even if $dontWrapQtApps is set.
+# Note: $qtWrapperArgs still gets defined even if ${dontWrapQtApps-} is set.
 wrapQtAppsHook() {
    # skip this hook when requested
-    [ -z "$dontWrapQtApps" ] || return 0
+    [ -z "${dontWrapQtApps-}" ] || return 0

    # guard against running multiple times (e.g. due to propagation)
    [ -z "$wrapQtAppsHookHasRun" ] || return 0
@@ -363,7 +363,7 @@ let

        npm ${forceOfflineFlag} --nodedir=${nodeSources} ${npmFlags} ${stdenv.lib.optionalString production "--production"} rebuild

-        if [ "$dontNpmInstall" != "1" ]
+        if [ "''${dontNpmInstall-}" != "1" ]
        then
            # NPM tries to download packages even when they already exist if npm-shrinkwrap is used.
            rm -f npm-shrinkwrap.json
@@ -43,8 +43,8 @@ buildPythonPackage rec {
  '';

  preConfigure = ''
-    [ -z "$dontPlacateNuget" ] && placate-nuget.sh
-    [ -z "$dontPlacatePaket" ] && placate-paket.sh
+    [ -z "''${dontPlacateNuget-}" ] && placate-nuget.sh
+    [ -z "''${dontPlacatePaket-}" ] && placate-paket.sh
  '';

  nativeBuildInputs = [
@@ -99,7 +99,7 @@ stdenv.mkDerivation ((builtins.removeAttrs attrs ["source"]) // {
    runHook preUnpack

    if [[ -f $src && $src == *.gem ]]; then
-      if [[ -z "$dontBuild" ]]; then
+      if [[ -z "''${dontBuild-}" ]]; then
        # we won't know the name of the directory that RubyGems creates,
        # so we'll just use a glob to find it and move it over.
        gempkg="$src"
@@ -46,14 +46,14 @@ stdenv.mkDerivation {
      # JRE by looking for java.  The latter allows just the JRE to be
      # used with (say) ECJ as the compiler.  Finally, allow the GNU
      # JVM.
-      if [ -z "\$JAVA_HOME" ]; then
+      if [ -z "\''${JAVA_HOME-}" ]; then
          for i in javac java gij; do
              if p="\$(type -p \$i)"; then
                  export JAVA_HOME="\$(${coreutils}/bin/dirname \$(${coreutils}/bin/dirname \$(${coreutils}/bin/readlink -f \$p)))"
                  break
              fi
          done
-          if [ -z "\$JAVA_HOME" ]; then
+          if [ -z "\''${JAVA_HOME-}" ]; then
              echo "\$0: cannot find the JDK or JRE" >&2
              exit 1
          fi
@@ -46,14 +46,14 @@ stdenv.mkDerivation {
      # JRE by looking for java.  The latter allows just the JRE to be
      # used with (say) ECJ as the compiler.  Finally, allow the GNU
      # JVM.
-      if [ -z "\$JAVA_HOME" ]; then
+      if [ -z "\''${JAVA_HOME-}" ]; then
          for i in javac java gij; do
              if p="\$(type -p \$i)"; then
                  export JAVA_HOME="\$(${coreutils}/bin/dirname \$(${coreutils}/bin/dirname \$(${coreutils}/bin/readlink -f \$p)))"
                  break
              fi
          done
-          if [ -z "\$JAVA_HOME" ]; then
+          if [ -z "\''${JAVA_HOME-}" ]; then
              echo "\$0: cannot find the JDK or JRE" >&2
              exit 1
          fi
@@ -20,17 +20,17 @@ cmakeConfigurePhase() {
        export CTEST_PARALLEL_LEVEL=$NIX_BUILD_CORES
    fi

-    if [ -z "$dontFixCmake" ]; then
+    if [ -z "${dontFixCmake-}" ]; then
        fixCmakeFiles .
    fi

-    if [ -z "$dontUseCmakeBuildDir" ]; then
+    if [ -z "${dontUseCmakeBuildDir-}" ]; then
        mkdir -p build
        cd build
        cmakeDir=${cmakeDir:-..}
    fi

-    if [ -z "$dontAddPrefix" ]; then
+    if [ -z "${dontAddPrefix-}" ]; then
        cmakeFlags="-DCMAKE_INSTALL_PREFIX=$prefix $cmakeFlags"
    fi

@@ -84,7 +84,7 @@ cmakeConfigurePhase() {
    cmakeFlags="-DCMAKE_INSTALL_LOCALEDIR=${!outputLib}/share/locale $cmakeFlags"

    # Don’t build tests when doCheck = false
-    if [ -z "$doCheck" ]; then
+    if [ -z "${doCheck-}" ]; then
        cmakeFlags="-DBUILD_TESTING=OFF $cmakeFlags"
    fi

@@ -99,7 +99,7 @@ cmakeConfigurePhase() {
    cmakeFlags="-DCMAKE_FIND_PACKAGE_NO_PACKAGE_REGISTRY=ON $cmakeFlags"
    cmakeFlags="-DCMAKE_FIND_PACKAGE_NO_SYSTEM_PACKAGE_REGISTRY=ON $cmakeFlags"

-    if [ "$buildPhase" = ninjaBuildPhase ]; then
+    if [ "${buildPhase-}" = ninjaBuildPhase ]; then
        cmakeFlags="-GNinja $cmakeFlags"
    fi

@@ -115,7 +115,7 @@ cmakeConfigurePhase() {
    runHook postConfigure
 }

-if [ -z "$dontUseCmakeConfigure" -a -z "$configurePhase" ]; then
+if [ -z "${dontUseCmakeConfigure-}" -a -z "${configurePhase-}" ]; then
    setOutputFlags=
    configurePhase=cmakeConfigurePhase
 fi
@@ -9,6 +9,6 @@ gnConfigurePhase() {
    runHook postConfigure
 }

-if [ -z "$dontUseGnConfigure" -a -z "$configurePhase" ]; then
+if [ -z "${dontUseGnConfigure-}" -a -z "${configurePhase-}" ]; then
    configurePhase=gnConfigurePhase
 fi
@@ -1,7 +1,7 @@
 mesonConfigurePhase() {
    runHook preConfigure

-    if [ -z "$dontAddPrefix" ]; then
+    if [ -z "${dontAddPrefix-}" ]; then
        mesonFlags="--prefix=$prefix $mesonFlags"
    fi

@@ -36,7 +36,7 @@ mesonConfigurePhase() {
    runHook postConfigure
 }

-if [ -z "$dontUseMesonConfigure" -a -z "$configurePhase" ]; then
+if [ -z "${dontUseMesonConfigure-}" -a -z "${configurePhase-}" ]; then
    setOutputFlags=
    configurePhase=mesonConfigurePhase
 fi
@@ -19,7 +19,7 @@ ninjaBuildPhase() {
    runHook postBuild
 }

-if [ -z "$dontUseNinjaBuild" -a -z "$buildPhase" ]; then
+if [ -z "${dontUseNinjaBuild-}" -a -z "${buildPhase-}" ]; then
    buildPhase=ninjaBuildPhase
 fi

@@ -38,7 +38,7 @@ ninjaInstallPhase() {
    runHook postInstall
 }

-if [ -z "$dontUseNinjaInstall" -a -z "$installPhase" ]; then
+if [ -z "${dontUseNinjaInstall-}" -a -z "${installPhase-}" ]; then
    installPhase=ninjaInstallPhase
 fi

@@ -73,6 +73,6 @@ ninjaCheckPhase() {
    runHook postCheck
 }

-if [ -z "$dontUseNinjaCheck" -a -z "$checkPhase" ]; then
+if [ -z "${dontUseNinjaCheck-}" -a -z "${checkPhase-}" ]; then
    checkPhase=ninjaCheckPhase
 fi
@@ -71,14 +71,14 @@ sconsCheckPhase() {
    runHook postCheck
 }

-if [ -z "$buildPhase" ]; then
+if [ -z "${buildPhase-}" ]; then
    buildPhase=sconsBuildPhase
 fi

-if [ -z "$dontUseSconsInstall" -a -z "$installPhase" ]; then
+if [ -z "${dontUseSconsInstall-}" -a -z "${installPhase-}" ]; then
    installPhase=sconsInstallPhase
 fi

-if [ -z "$checkPhase" ]; then
+if [ -z "${checkPhase-}" ]; then
    checkPhase=sconsCheckPhase
 fi
@@ -2,7 +2,7 @@
 # directories from the RPATH of every library or executable in every
 # output.

-fixupOutputHooks+=('if [ -z "$dontPatchELF" ]; then patchELF "$prefix"; fi')
+fixupOutputHooks+=('if [ -z "${dontPatchELF-}" ]; then patchELF "$prefix"; fi')

 patchELF() {
    local dir="$1"
@@ -14,6 +14,6 @@ premakeConfigurePhase() {
    runHook postConfigure
 }

-if [ -z "$configurePhase" ]; then
+if [ -z "${configurePhase-}" ]; then
    configurePhase=premakeConfigurePhase
 fi
@@ -64,7 +64,7 @@ index 00000000..3ea84e2d
 +header() { echo "$1"; }
 +stopNest() { true; }
 +
-+fixupOutputHooks+=('if [ -z "$dontPatchShebangs" -a -e "$prefix" ]; then patchShebangs "$prefix"; fi')
+fixupOutputHooks+=('if [ -z "${dontPatchShebangs-}" -a -e "$prefix" ]; then patchShebangs "$prefix"; fi')
 +
 +patchShebangs() {
 +    local dir="$1"
@@ -20,7 +20,7 @@ xcbuildInstallPhase () {
 }

 buildPhase=xcbuildBuildPhase
-if [ -z "$installPhase" ]; then
+if [ -z "${installPhase-}" ]; then
    installPhase=xcbuildInstallPhase
 fi

@@ -179,7 +179,7 @@ let
      '' else "") + (if isModular then ''
        mkdir -p $dev
        cp vmlinux $dev/
-        if [ -z "$dontStrip" ]; then
+        if [ -z "''${dontStrip-}" ]; then
          installFlagsArray+=("INSTALL_MOD_STRIP=1")
        fi
        make modules_install $makeFlags "''${makeFlagsArray[@]}" \
@@ -14,6 +14,6 @@ imakeConfigurePhase() {
    runHook postConfigure
 }

-if [ -z "$dontUseImakeConfigure" -a -z "$configurePhase" ]; then
+if [ -z "${dontUseImakeConfigure-}" -a -z "${configurePhase-}" ]; then
    configurePhase=imakeConfigurePhase
 fi
@@ -1,7 +1,7 @@
 fixupOutputHooks+=(_cygwinFixAutoImageBase)

 _cygwinFixAutoImageBase() {
-    if [ "$dontRebase" == 1 ] || [ ! -d "$prefix" ]; then
+    if [ "${dontRebase-}" == 1 ] || [ ! -d "$prefix" ]; then
        return
    fi
    find "$prefix" -name "*.dll" -type f | while read DLL; do
@@ -1,7 +1,7 @@
 fixupOutputHooks+=(_cygwinFixAutoImageBase)

 _cygwinFixAutoImageBase() {
-    if [ "$dontRebase" == 1 ] || [ ! -d "$prefix" ]; then
+    if [ "${dontRebase-}" == 1 ] || [ ! -d "$prefix" ]; then
        return
    fi
    find "$prefix" -name "*.dll" -type f | while read DLL; do
@@ -17,10 +17,6 @@ fi
 # code). The hooks for <hookName> are the shell function or variable
 # <hookName>, and the values of the shell array ‘<hookName>Hooks’.
 runHook() {
-    local oldOpts="-u"
-    shopt -qo nounset || oldOpts="+u"
-    set -u # May be called from elsewhere, so do `set -u`.
-
    local hookName="$1"
    shift
    local hooksSlice="${hookName%Hook}Hooks[@]"
@@ -30,10 +26,8 @@ runHook() {
    # undefined.
    for hook in "_callImplicitHook 0 $hookName" ${!hooksSlice+"${!hooksSlice}"}; do
        _eval "$hook" "$@"
-        set -u # To balance `_eval`
    done

-    set "$oldOpts"
    return 0
 }

@@ -41,10 +35,6 @@ runHook() {
 # Run all hooks with the specified name, until one succeeds (returns a
 # zero exit code). If none succeed, return a non-zero exit code.
 runOneHook() {
-    local oldOpts="-u"
-    shopt -qo nounset || oldOpts="+u"
-    set -u # May be called from elsewhere, so do `set -u`.
-
    local hookName="$1"
    shift
    local hooksSlice="${hookName%Hook}Hooks[@]"
@@ -56,10 +46,8 @@ runOneHook() {
            ret=0
            break
        fi
-        set -u # To balance `_eval`
    done

-    set "$oldOpts"
    return "$ret"
 }

@@ -70,17 +58,13 @@ runOneHook() {
 # environment variables) and from shell scripts (as functions). If you
 # want to allow multiple hooks, use runHook instead.
 _callImplicitHook() {
-    set -u
    local def="$1"
    local hookName="$2"
    if declare -F "$hookName" > /dev/null; then
-        set +u
        "$hookName"
    elif type -p "$hookName" > /dev/null; then
-        set +u
        source "$hookName"
    elif [ -n "${!hookName:-}" ]; then
-        set +u
        eval "${!hookName}"
    else
        return "$def"
@@ -96,13 +80,10 @@ _callImplicitHook() {
 # command can take them
 _eval() {
    if declare -F "$1" > /dev/null 2>&1; then
-        set +u
        "$@" # including args
    else
-        set +u
        eval "$1"
    fi
-    # `run*Hook` reenables `set -u`
 }


@@ -190,12 +171,12 @@ addToSearchPath() {
 # so it is defined here but tried after the hook.
 _addRpathPrefix() {
    if [ "${NIX_NO_SELF_RPATH:-0}" != 1 ]; then
-        export NIX_LDFLAGS="-rpath $1/lib $NIX_LDFLAGS"
+        export NIX_LDFLAGS="-rpath $1/lib ${NIX_LDFLAGS-}"
        if [ -n "${NIX_LIB64_IN_SELF_RPATH:-}" ]; then
-            export NIX_LDFLAGS="-rpath $1/lib64 $NIX_LDFLAGS"
+            export NIX_LDFLAGS="-rpath $1/lib64 ${NIX_LDFLAGS-}"
        fi
        if [ -n "${NIX_LIB32_IN_SELF_RPATH:-}" ]; then
-            export NIX_LDFLAGS="-rpath $1/lib32 $NIX_LDFLAGS"
+            export NIX_LDFLAGS="-rpath $1/lib32 ${NIX_LDFLAGS-}"
        fi
    fi
 }
@@ -489,11 +470,7 @@ activatePackage() {
    (( "$hostOffset" <= "$targetOffset" )) || exit -1

    if [ -f "$pkg" ]; then
-        local oldOpts="-u"
-        shopt -qo nounset || oldOpts="+u"
-        set +u
        source "$pkg"
-        set "$oldOpts"
    fi

    # Only dependencies whose host platform is guaranteed to match the
@@ -512,11 +489,7 @@ activatePackage() {
    fi

    if [[ -f "$pkg/nix-support/setup-hook" ]]; then
-        local oldOpts="-u"
-        shopt -qo nounset || oldOpts="+u"
-        set +u
        source "$pkg/nix-support/setup-hook"
-        set "$oldOpts"
    fi
 }

@@ -1264,19 +1237,11 @@ showPhaseHeader() {

 genericBuild() {
    if [ -f "${buildCommandPath:-}" ]; then
-        local oldOpts="-u"
-        shopt -qo nounset || oldOpts="+u"
-        set +u
        source "$buildCommandPath"
-        set "$oldOpts"
        return
    fi
    if [ -n "${buildCommand:-}" ]; then
-        local oldOpts="-u"
-        shopt -qo nounset || oldOpts="+u"
-        set +u
        eval "$buildCommand"
-        set "$oldOpts"
        return
    fi

@@ -1306,11 +1271,7 @@ genericBuild() {

        # Evaluate the variable named $curPhase if it exists, otherwise the
        # function named $curPhase.
-        local oldOpts="-u"
-        shopt -qo nounset || oldOpts="+u"
-        set +u
        eval "${!curPhase:-$curPhase}"
-        set "$oldOpts"

        if [ "$curPhase" = unpackPhase ]; then
            cd "${sourceRoot:-.}"
@@ -3,4 +3,4 @@ mimeinfoPreFixupPhase() {
    rm -f $out/share/applications/mimeinfo.cache
 }

-preFixupPhases="$preFixupPhases mimeinfoPreFixupPhase"
+preFixupPhases="${preFixupPhases-} mimeinfoPreFixupPhase"