Unverified Commit 2d64877f authored by Wolfgang Walther's avatar Wolfgang Walther
Browse files

replaceVars: allow exemptions 

replaceVars has a checkPhase to confirm that no left-over @...@ patterns
remain. Since it's not possible to use "placeholder" with replaceVars,
the substitution of some patterns must be delayed to a later step.

By passing "null" for those keys explicitly, replaceVars can make an
exemption *just for this case*, but keep checking all other references.
parent c4c7cbaf

pkgs/build-support/replace-vars/default.nix

+20 −11
Original line number Diff line number Diff line
@@ -11,8 +11,8 @@ 


  Any unmatched variable names in the file at the provided path will cause a build failure.



  Any remaining text that matches `@[A-Za-z_][0-9A-Za-z_'-]@` in the output after replacement

  has occurred will cause a build failure.

  By default, any remaining text that matches `@[A-Za-z_][0-9A-Za-z_'-]@` in the output after replacement

  has occurred will cause a build failure. Variables can be excluded from this check by passing "null" for them.



  # Inputs
@@ -20,7 +20,8 @@ 
  : The file in which to replace variables.



  `attrs` (AttrsOf String)

  : Each entry in this set corresponds to a `--subst-var-by` entry in [`substitute`](https://nixos.org/manual/nixpkgs/stable/#fun-substitute).

  : Each entry in this set corresponds to a `--subst-var-by` entry in [`substitute`](https://nixos.org/manual/nixpkgs/stable/#fun-substitute) or

    null to keep it unchanged.



  # Example
@@ -36,13 +37,19 @@ path: attrs: 


let

  # We use `--replace-fail` instead of `--subst-var-by` so that if the thing isn't there, we fail.

  subst-var-by = name: value: [

  subst-var-by =

    name: value:

    lib.optionals (value != null) [

      "--replace-fail"

      (lib.escapeShellArg "@${name}@")

      (lib.escapeShellArg value)

    ];



  replacements = lib.concatLists (lib.mapAttrsToList subst-var-by attrs);



  left-overs = map ({ name, ... }: name) (

    builtins.filter ({ value, ... }: value == null) (lib.attrsToList attrs)

  );

in



stdenvNoCC.mkDerivation {
@@ -62,13 +69,15 @@ stdenvNoCC.mkDerivation { 
  # Look for Nix identifiers surrounded by `@` that aren't substituted.

  checkPhase =

    let

      regex = lib.escapeShellArg "@[a-zA-Z_][0-9A-Za-z_'-]*@";

      lookahead =

        if builtins.length left-overs == 0 then "" else "(?!${builtins.concatStringsSep "|" left-overs}@)";

      regex = lib.escapeShellArg "@${lookahead}[a-zA-Z_][0-9A-Za-z_'-]*@";

    in

    ''

      runHook preCheck

      if grep -qe ${regex} "$out"; then

      if grep -Pqe ${regex} "$out"; then

        echo The following look like unsubstituted Nix identifiers that remain in "$out":

        grep -oe ${regex} "$out"

        grep -Poe ${regex} "$out"

        echo Use the more precise '`substitute`' function if this check is in error.

        exit 1

      fi

pkgs/test/replace-vars/default.nix

+43 −0
Original line number Diff line number Diff line
@@ -69,6 +69,49 @@ in 
        # Shouldn't see the "cannot detect" version.

        ! grep -q -F "cannot detect due to space" $failed/testBuildFailure.log



        touch $out

      '';



  replaceVars-succeeds-with-exemption = testEqualContents {

    assertion = "replaceVars-succeeds-with-exemption";

    actual = replaceVars ./source.txt {

      free = "free";

      "equal in" = "are the same in";

      brotherhood = null;

    };



    expected = builtins.toFile "expected" ''

      All human beings are born free and are the same in dignity and rights.

      They are endowed with reason and conscience and should act towards

      one another in a spirit of @brotherhood@.



        -- eroosevelt@humanrights.un.org

    '';

  };



  replaceVars-fails-in-check-phase-with-exemption =

    runCommand "replaceVars-fails-with-exemption"

      {

        failed =

          let

            src = builtins.toFile "source.txt" ''

              @a@

              @b@

              @c@

            '';

          in

          testBuildFailure (

            replaceVars src {

              a = "a";

              b = null;

            }

          );

      }

      ''

        grep -e "unsubstituted Nix identifiers.*source.txt" $failed/testBuildFailure.log

        grep -F "@c@" $failed/testBuildFailure.log

        ! grep -F "@b@" $failed/testBuildFailure.log



        touch $out

      '';

}

pkgs/tools/virtualization/mkosi/default.nix

+2 −2
Original line number Diff line number Diff line
@@ -68,7 +68,7 @@ buildPythonApplication rec { 
      (replaceVars ./0001-Use-wrapped-binaries-instead-of-Python-interpreter.patch {

        UKIFY = "${systemdForMkosi}/lib/systemd/ukify";

        PYTHON_PEFILE = "${python3pefile}/bin/python3.12";

        MKOSI_SANDBOX = "~MKOSI_SANDBOX~"; # to satisfy replaceVars, will be replaced in postPatch

        MKOSI_SANDBOX = null; # will be replaced in postPatch

      })

      (replaceVars ./0002-Fix-library-resolving.patch {

        LIBC = "${stdenv.cc.libc}/lib/libc.so.6";
@@ -84,7 +84,7 @@ buildPythonApplication rec { 
  postPatch = ''

    # As we need the $out reference, we can't use `replaceVars` here.

    substituteInPlace mkosi/run.py \

      --replace-fail '~MKOSI_SANDBOX~' "\"$out/bin/mkosi-sandbox\""

      --replace-fail '@MKOSI_SANDBOX@' "\"$out/bin/mkosi-sandbox\""

  '';



  nativeBuildInputs = [