treewide: use optionalString

21 files changed, 39 insertions, 44 deletions

diff --git a/pkgs/build-support/alternatives/blas/default.nix b/pkgs/build-support/alternatives/blas/default.nix
index 7186675a5c6..fec2d0526bb 100644
--- a/pkgs/build-support/alternatives/blas/default.nix
+++ b/pkgs/build-support/alternatives/blas/default.nix
@@ -83,12 +83,12 @@ stdenv.mkDerivation {
 '' + (if stdenv.hostPlatform.parsed.kernel.execFormat.name == "elf" then ''
   patchelf --set-soname libblas${canonicalExtension} $out/lib/libblas${canonicalExtension}
   patchelf --set-rpath "$(patchelf --print-rpath $out/lib/libblas${canonicalExtension}):${lib.getLib blasProvider'}/lib" $out/lib/libblas${canonicalExtension}
-'' else if stdenv.hostPlatform.isDarwin then ''
+'' else lib.optionalString (stdenv.hostPlatform.isDarwin) ''
   install_name_tool \
     -id $out/lib/libblas${canonicalExtension} \
     -add_rpath ${lib.getLib blasProvider'}/lib \
     $out/lib/libblas${canonicalExtension}
-'' else "") + ''
+'') + ''
 
   if [ "$out/lib/libblas${canonicalExtension}" != "$out/lib/libblas${stdenv.hostPlatform.extensions.sharedLibrary}" ]; then
     ln -s $out/lib/libblas${canonicalExtension} "$out/lib/libblas${stdenv.hostPlatform.extensions.sharedLibrary}"
@@ -115,12 +115,12 @@ EOF
 '' + (if stdenv.hostPlatform.parsed.kernel.execFormat.name == "elf" then ''
   patchelf --set-soname libcblas${canonicalExtension} $out/lib/libcblas${canonicalExtension}
   patchelf --set-rpath "$(patchelf --print-rpath $out/lib/libcblas${canonicalExtension}):${lib.getLib blasProvider'}/lib" $out/lib/libcblas${canonicalExtension}
-'' else if stdenv.hostPlatform.isDarwin then ''
+'' else lib.optionalString stdenv.hostPlatform.isDarwin ''
   install_name_tool \
     -id $out/lib/libcblas${canonicalExtension} \
     -add_rpath ${lib.getLib blasProvider'}/lib \
     $out/lib/libcblas${canonicalExtension}
-'' else "") + ''
+'') + ''
   if [ "$out/lib/libcblas${canonicalExtension}" != "$out/lib/libcblas${stdenv.hostPlatform.extensions.sharedLibrary}" ]; then
     ln -s $out/lib/libcblas${canonicalExtension} "$out/lib/libcblas${stdenv.hostPlatform.extensions.sharedLibrary}"
   fi
diff --git a/pkgs/build-support/alternatives/lapack/default.nix b/pkgs/build-support/alternatives/lapack/default.nix
index 80fb7be8c1e..9886a035e4e 100644
--- a/pkgs/build-support/alternatives/lapack/default.nix
+++ b/pkgs/build-support/alternatives/lapack/default.nix
@@ -54,10 +54,10 @@ stdenv.mkDerivation {
   cp -L "$liblapack" $out/lib/liblapack${canonicalExtension}
   chmod +w $out/lib/liblapack${canonicalExtension}
 
-'' + (if stdenv.hostPlatform.parsed.kernel.execFormat.name == "elf" then ''
+'' + (lib.optionalString (stdenv.hostPlatform.parsed.kernel.execFormat.name == "elf") ''
   patchelf --set-soname liblapack${canonicalExtension} $out/lib/liblapack${canonicalExtension}
   patchelf --set-rpath "$(patchelf --print-rpath $out/lib/liblapack${canonicalExtension}):${lapackProvider'}/lib" $out/lib/liblapack${canonicalExtension}
-'' else "") + ''
+'') + ''
 
   if [ "$out/lib/liblapack${canonicalExtension}" != "$out/lib/liblapack${stdenv.hostPlatform.extensions.sharedLibrary}" ]; then
     ln -s $out/lib/liblapack${canonicalExtension} "$out/lib/liblapack${stdenv.hostPlatform.extensions.sharedLibrary}"
@@ -83,10 +83,10 @@ EOF
   cp -L "$liblapacke" $out/lib/liblapacke${canonicalExtension}
   chmod +w $out/lib/liblapacke${canonicalExtension}
 
-'' + (if stdenv.hostPlatform.parsed.kernel.execFormat.name == "elf" then ''
+'' + (lib.optionalString (stdenv.hostPlatform.parsed.kernel.execFormat.name == "elf") ''
   patchelf --set-soname liblapacke${canonicalExtension} $out/lib/liblapacke${canonicalExtension}
   patchelf --set-rpath "$(patchelf --print-rpath $out/lib/liblapacke${canonicalExtension}):${lib.getLib lapackProvider'}/lib" $out/lib/liblapacke${canonicalExtension}
-'' else "") + ''
+'') + ''
 
   if [ -f "$out/lib/liblapacke.so.3" ]; then
     ln -s $out/lib/liblapacke.so.3 $out/lib/liblapacke.so
diff --git a/pkgs/build-support/bintools-wrapper/default.nix b/pkgs/build-support/bintools-wrapper/default.nix
index 45ae3eba9b4..6e33f6189a4 100644
--- a/pkgs/build-support/bintools-wrapper/default.nix
+++ b/pkgs/build-support/bintools-wrapper/default.nix
@@ -92,9 +92,8 @@ let
     else "";
 
   expand-response-params =
-    if buildPackages ? stdenv && buildPackages.stdenv.hasCC && buildPackages.stdenv.cc != "/dev/null"
-    then import ../expand-response-params { inherit (buildPackages) stdenv; }
-    else "";
+    lib.optionalString (buildPackages ? stdenv && buildPackages.stdenv.hasCC && buildPackages.stdenv.cc != "/dev/null")
+    (import ../expand-response-params { inherit (buildPackages) stdenv; });
 
 in
 
diff --git a/pkgs/build-support/build-bazel-package/default.nix b/pkgs/build-support/build-bazel-package/default.nix
index d1cd502e7e4..a3f331b23cb 100644
--- a/pkgs/build-support/build-bazel-package/default.nix
+++ b/pkgs/build-support/build-bazel-package/default.nix
@@ -118,10 +118,10 @@ stdenv.mkDerivation (fBuildAttrs // {
 
       # Remove all built in external workspaces, Bazel will recreate them when building
       rm -rf $bazelOut/external/{bazel_tools,\@bazel_tools.marker}
-      ${if removeRulesCC then "rm -rf $bazelOut/external/{rules_cc,\\@rules_cc.marker}" else ""}
+      ${lib.optionalString removeRulesCC "rm -rf $bazelOut/external/{rules_cc,\\@rules_cc.marker}"}
       rm -rf $bazelOut/external/{embedded_jdk,\@embedded_jdk.marker}
-      ${if removeLocalConfigCc then "rm -rf $bazelOut/external/{local_config_cc,\\@local_config_cc.marker}" else ""}
-      ${if removeLocal then "rm -rf $bazelOut/external/{local_*,\\@local_*.marker}" else ""}
+      ${lib.optionalString removeLocalConfigCc "rm -rf $bazelOut/external/{local_config_cc,\\@local_config_cc.marker}"}
+      ${lib.optionalString removeLocal "rm -rf $bazelOut/external/{local_*,\\@local_*.marker}"}
 
       # Clear markers
       find $bazelOut/external -name '@*\.marker' -exec sh -c 'echo > {}' \;
diff --git a/pkgs/build-support/build-fhs-userenv-bubblewrap/env.nix b/pkgs/build-support/build-fhs-userenv-bubblewrap/env.nix
index 7ebcba73708..c4d967a11c6 100644
--- a/pkgs/build-support/build-fhs-userenv-bubblewrap/env.nix
+++ b/pkgs/build-support/build-fhs-userenv-bubblewrap/env.nix
@@ -212,7 +212,7 @@ in stdenv.mkDerivation {
     cd $out
     ${extraBuildCommands}
     cd $out
-    ${if isMultiBuild then extraBuildCommandsMulti else ""}
+    ${lib.optionalString isMultiBuild extraBuildCommandsMulti}
   '';
   preferLocalBuild = true;
   allowSubstitutes = false;
diff --git a/pkgs/build-support/build-fhs-userenv/env.nix b/pkgs/build-support/build-fhs-userenv/env.nix
index 09457caecb8..fbc50c2dc25 100644
--- a/pkgs/build-support/build-fhs-userenv/env.nix
+++ b/pkgs/build-support/build-fhs-userenv/env.nix
@@ -1,4 +1,4 @@
-{ stdenv, buildEnv, writeText, pkgs, pkgsi686Linux }:
+{ stdenv, lib, buildEnv, writeText, pkgs, pkgsi686Linux }:
 
 { name
 , profile ? ""
@@ -237,7 +237,7 @@ in stdenv.mkDerivation {
     cd $out
     ${extraBuildCommands}
     cd $out
-    ${if isMultiBuild then extraBuildCommandsMulti else ""}
+    ${lib.optionalString isMultiBuild extraBuildCommandsMulti}
   '';
   preferLocalBuild = true;
   allowSubstitutes = false;
diff --git a/pkgs/build-support/cc-wrapper/default.nix b/pkgs/build-support/cc-wrapper/default.nix
index 2f3b2d8e378..6520c04f5e8 100644
--- a/pkgs/build-support/cc-wrapper/default.nix
+++ b/pkgs/build-support/cc-wrapper/default.nix
@@ -59,9 +59,7 @@ let
   suffixSalt = replaceStrings ["-" "."] ["_" "_"] targetPlatform.config;
 
   expand-response-params =
-    if (buildPackages.stdenv.hasCC or false) && buildPackages.stdenv.cc != "/dev/null"
-    then import ../expand-response-params { inherit (buildPackages) stdenv; }
-    else "";
+    lib.optionalString ((buildPackages.stdenv.hasCC or false) && buildPackages.stdenv.cc != "/dev/null") (import ../expand-response-params { inherit (buildPackages) stdenv; });
 
   useGccForLibs = isClang
     && libcxx == null
diff --git a/pkgs/build-support/fetchdocker/credentials.nix b/pkgs/build-support/fetchdocker/credentials.nix
index 6d084d3c77e..da198483268 100644
--- a/pkgs/build-support/fetchdocker/credentials.nix
+++ b/pkgs/build-support/fetchdocker/credentials.nix
@@ -35,4 +35,4 @@ let
     ({prefix, path}: "DOCKER_CREDENTIALS" == prefix)
     builtins.nixPath);
 in
-  if (pathParts != []) then (builtins.head pathParts).path else ""
+  lib.optionalString (pathParts != []) ((builtins.head pathParts).path)
diff --git a/pkgs/build-support/fetchfossil/default.nix b/pkgs/build-support/fetchfossil/default.nix
index 3a4876bc5de..7866c403ec4 100644
--- a/pkgs/build-support/fetchfossil/default.nix
+++ b/pkgs/build-support/fetchfossil/default.nix
@@ -1,9 +1,9 @@
-{stdenv, fossil, cacert}:
+{stdenv, lib, fossil, cacert}:
 
 {name ? null, url, rev, sha256}:
 
 stdenv.mkDerivation {
-  name = "fossil-archive" + (if name != null then "-${name}" else "");
+  name = "fossil-archive" + (lib.optionalString (name != null) "-${name}");
   builder = ./builder.sh;
   nativeBuildInputs = [fossil cacert];
 
diff --git a/pkgs/build-support/fetchgit/default.nix b/pkgs/build-support/fetchgit/default.nix
index 2d0b4b20ef8..56973f5d367 100644
--- a/pkgs/build-support/fetchgit/default.nix
+++ b/pkgs/build-support/fetchgit/default.nix
@@ -7,9 +7,7 @@
 
     short = builtins.substring 0 7 rev;
 
-    appendShort = if (builtins.match "[a-f0-9]*" rev) != null
-      then "-${short}"
-      else "";
+    appendShort = lib.optionalString ((builtins.match "[a-f0-9]*" rev) != null) "-${short}";
   in "${if matched == null then base else builtins.head matched}${appendShort}";
 in
 { url, rev ? "HEAD", md5 ? "", sha256 ? "", hash ? "", leaveDotGit ? deepClone
diff --git a/pkgs/build-support/fetchhg/default.nix b/pkgs/build-support/fetchhg/default.nix
index 15309d0a195..b3c28fb0e26 100644
--- a/pkgs/build-support/fetchhg/default.nix
+++ b/pkgs/build-support/fetchhg/default.nix
@@ -12,13 +12,13 @@ if md5 != null then
 else
 # TODO: statically check if mercurial as the https support if the url starts woth https.
 stdenvNoCC.mkDerivation {
-  name = "hg-archive" + (if name != null then "-${name}" else "");
+  name = "hg-archive" + (lib.optionalString (name != null) "-${name}");
   builder = ./builder.sh;
   nativeBuildInputs = [mercurial];
 
   impureEnvVars = lib.fetchers.proxyImpureEnvVars;
 
-  subrepoClause = if fetchSubrepos then "S" else "";
+  subrepoClause = lib.optionalString fetchSubrepos "S";
 
   outputHashAlgo = "sha256";
   outputHashMode = "recursive";
diff --git a/pkgs/build-support/fetchpatch/default.nix b/pkgs/build-support/fetchpatch/default.nix
index 3ebe797f736..d059715cedc 100644
--- a/pkgs/build-support/fetchpatch/default.nix
+++ b/pkgs/build-support/fetchpatch/default.nix
@@ -18,7 +18,7 @@
 let
   args' = if relative != null then {
     stripLen = 1 + lib.length (lib.splitString "/" relative) + stripLen;
-    extraPrefix = if extraPrefix != null then extraPrefix else "";
+    extraPrefix = lib.optionalString (extraPrefix != null) extraPrefix;
   } else {
     inherit stripLen extraPrefix;
   };
diff --git a/pkgs/build-support/nuke-references/default.nix b/pkgs/build-support/nuke-references/default.nix
index c2dfe27b2c6..8f02c559238 100644
--- a/pkgs/build-support/nuke-references/default.nix
+++ b/pkgs/build-support/nuke-references/default.nix
@@ -36,6 +36,6 @@ stdenvNoCC.mkDerivation {
     inherit perl;
     inherit (builtins) storeDir;
     shell = lib.getBin shell + (shell.shellPath or "");
-    signingUtils = if darwinCodeSign then signingUtils else "";
+    signingUtils = lib.optionalString darwinCodeSign signingUtils;
   };
 }
diff --git a/pkgs/build-support/release/binary-tarball.nix b/pkgs/build-support/release/binary-tarball.nix
index 168343c8082..24d5b2e1caf 100644
--- a/pkgs/build-support/release/binary-tarball.nix
+++ b/pkgs/build-support/release/binary-tarball.nix
@@ -10,7 +10,7 @@
    directory, so the Makefile of the package should support DESTDIR.
 */
 
-{ src, stdenv
+{ src, lib, stdenv
 , name ? "binary-tarball"
 , ... } @ args:
 
@@ -30,7 +30,7 @@ stdenv.mkDerivation (
   // args //
 
   {
-    name = name + (if src ? version then "-" + src.version else "");
+    name = name + (lib.optionalString (src ? version) "-${src.version}");
 
     postHook = ''
       mkdir -p $out/nix-support
diff --git a/pkgs/build-support/release/debian-build.nix b/pkgs/build-support/release/debian-build.nix
index 679adad827d..6e08caf0a4e 100644
--- a/pkgs/build-support/release/debian-build.nix
+++ b/pkgs/build-support/release/debian-build.nix
@@ -24,7 +24,7 @@ vmTools.runInLinuxImage (stdenv.mkDerivation (
   // removeAttrs args ["vmTools" "lib"] //
 
   {
-    name = name + "-" + diskImage.name + (if src ? version then "-" + src.version else "");
+    name = name + "-" + diskImage.name + (lib.optionalString (src ? version) "-${src.version}");
 
     # !!! cut&paste from rpm-build.nix
     postHook = ''
diff --git a/pkgs/build-support/release/default.nix b/pkgs/build-support/release/default.nix
index da1078369a5..ee414ea3280 100644
--- a/pkgs/build-support/release/default.nix
+++ b/pkgs/build-support/release/default.nix
@@ -11,7 +11,7 @@ rec {
   makeSourceTarball = sourceTarball; # compatibility
 
   binaryTarball = args: import ./binary-tarball.nix (
-    { inherit stdenv;
+    { inherit lib stdenv;
     } // args);
 
   mvnBuild = args: import ./maven-build.nix (
@@ -38,7 +38,7 @@ rec {
     } // args);
 
   rpmBuild = args: import ./rpm-build.nix (
-    { inherit vmTools;
+    { inherit lib vmTools;
     } // args);
 
   debBuild = args: import ./debian-build.nix (
diff --git a/pkgs/build-support/release/maven-build.nix b/pkgs/build-support/release/maven-build.nix
index daee44b85ac..f618032724c 100644
--- a/pkgs/build-support/release/maven-build.nix
+++ b/pkgs/build-support/release/maven-build.nix
@@ -22,7 +22,7 @@ in
 
 stdenv.mkDerivation ( {
   inherit name src;
-  phases = "setupPhase unpackPhase patchPhase mvnCompile ${if doTestCompile then "mvnTestCompile mvnTestJar" else ""} ${if doTest then "mvnTest" else ""} ${if doJavadoc then "mvnJavadoc" else ""} ${if doCheckstyle then "mvnCheckstyle" else ""} mvnJar mvnAssembly mvnRelease finalPhase";
+  phases = "setupPhase unpackPhase patchPhase mvnCompile ${lib.optionalString doTestCompile "mvnTestCompile mvnTestJar"} ${lib.optionalString doTest "mvnTest"} ${lib.optionalString doJavadoc "mvnJavadoc"} ${lib.optionalString doCheckstyle "mvnCheckstyle"} mvnJar mvnAssembly mvnRelease finalPhase";
 
   setupPhase = ''
     runHook preSetupPhase
@@ -88,9 +88,9 @@ stdenv.mkDerivation ( {
 
     echo "$releaseName" > $out/nix-support/hydra-release-name
 
-    ${if doRelease then  ''
+    ${lib.optionalString doRelease ''
     echo "file zip $out/release/$releaseName.zip" >> $out/nix-support/hydra-build-products
-    '' else ""}
+    ''}
   '';
 
   finalPhase = ''
diff --git a/pkgs/build-support/release/nix-build.nix b/pkgs/build-support/release/nix-build.nix
index 9578fbf482f..0498232d4d6 100644
--- a/pkgs/build-support/release/nix-build.nix
+++ b/pkgs/build-support/release/nix-build.nix
@@ -85,7 +85,7 @@ stdenv.mkDerivation (
   // removeAttrs args [ "lib" ] # Propagating lib causes the evaluation to fail, because lib is a function that can't be converted to a string
 
   // {
-    name = name + (if src ? version then "-" + src.version else "");
+    name = name + (lib.optionalString (src ? version) "-${src.version}");
 
     postHook = ''
       . ${./functions.sh}
@@ -167,7 +167,7 @@ stdenv.mkDerivation (
 
           echo "building out of source tree, from \`$PWD'..."
 
-          ${if preConfigure != null then preConfigure else ""}
+          ${lib.optionalString (preConfigure != null) preConfigure}
        '';
    }
    else {})
diff --git a/pkgs/build-support/release/rpm-build.nix b/pkgs/build-support/release/rpm-build.nix
index 47c01f2e66b..8f471147050 100644
--- a/pkgs/build-support/release/rpm-build.nix
+++ b/pkgs/build-support/release/rpm-build.nix
@@ -3,7 +3,7 @@
 
 { name ? "rpm-build"
 , diskImage
-, src, vmTools
+, src, lib, vmTools
 , ... } @ args:
 
 vmTools.buildRPM (
@@ -11,7 +11,7 @@ vmTools.buildRPM (
   removeAttrs args ["vmTools"] //
 
   {
-    name = name + "-" + diskImage.name + (if src ? version then "-" + src.version else "");
+    name = name + "-" + diskImage.name + (lib.optionalString (src ? version) "-${src.version}");
 
     preBuild = ''
       . ${./functions.sh}
diff --git a/pkgs/build-support/rust/build-rust-crate/default.nix b/pkgs/build-support/rust/build-rust-crate/default.nix
index 98030225bcb..435a942daa2 100644
--- a/pkgs/build-support/rust/build-rust-crate/default.nix
+++ b/pkgs/build-support/rust/build-rust-crate/default.nix
@@ -299,7 +299,7 @@ crate_: lib.makeOverridable
         );
 
       libName = if crate ? libName then crate.libName else crate.crateName;
-      libPath = if crate ? libPath then crate.libPath else "";
+      libPath = lib.optionalString (crate ? libPath) crate.libPath;
 
       # Seed the symbol hashes with something unique every time.
       # https://doc.rust-lang.org/1.0.0/rustc/metadata/loader/index.html#frobbing-symbols
diff --git a/pkgs/build-support/vm/default.nix b/pkgs/build-support/vm/default.nix
index 84754e58030..d63d17e23f8 100644
--- a/pkgs/build-support/vm/default.nix
+++ b/pkgs/build-support/vm/default.nix
@@ -406,7 +406,7 @@ rec {
       eval "$origPostHook"
     '';
 
-    origPostHook = if attrs ? postHook then attrs.postHook else "";
+    origPostHook = lib.optionalString (attrs ? postHook) attrs.postHook;
 
     /* Don't run Nix-specific build steps like patchelf. */
     fixupPhase = "true";