1 files changed, 41 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/tools/typesetting/tex/texlive/generate-fixed-hashes.nix b/nixpkgs/pkgs/tools/typesetting/tex/texlive/generate-fixed-hashes.nix
new file mode 100644
index 000000000000..738fef022010
--- /dev/null
+++ b/nixpkgs/pkgs/tools/typesetting/tex/texlive/generate-fixed-hashes.nix
@@ -0,0 +1,41 @@
+with import ../../../../.. { };
+
+with lib; let
+  # NOTE: the fixed naming scheme must match default.nix
+  # name for the URL
+  mkURLName = { pname, tlType, ... }: pname + lib.optionalString (tlType != "run" && tlType != "tlpkg") ".${tlType}";
+  # name + revision for the fixed output hashes
+  mkFixedName = { tlType, revision, extraRevision ? "", ... }@attrs: mkURLName attrs + (lib.optionalString (tlType == "tlpkg") ".tlpkg") + ".r${toString revision}${extraRevision}";
+
+  uniqueByName = fods: catAttrs "fod" (genericClosure {
+    startSet = map (fod: { key = fod.name; inherit fod; }) fods;
+    operator = _: [ ];
+  });
+
+  # ugly hack to extract combine from collection-latexextra, since it is masked by texlive.combine
+  combine = lib.findFirst (p: (lib.head p.pkgs).pname == "combine") { pkgs = []; } (lib.head texlive.collection-latexextra.pkgs).tlDeps;
+  all = concatLists (map (p: p.pkgs or []) (attrValues (removeAttrs texlive [ "bin" "combine" "combined" "tlpdb" ]))) ++ combine.pkgs;
+
+  # fixed hashes only for run, doc, source, tlpkg types
+  fods = sort (a: b: a.name < b.name) (uniqueByName (filter (p: isDerivation p && p.tlType != "bin") all));
+
+  computeHash = fod: runCommand "${fod.name}-fixed-hash"
+    { buildInputs = [ nix ]; inherit fod; }
+    ''echo -n "$(nix-hash --base32 --type sha256 "$fod")" >"$out"'';
+
+  hash = fod: fod.outputHash or (builtins.readFile (computeHash fod));
+  hashLine = fod: ''
+    "${mkFixedName fod}"="${hash fod}";
+  '';
+in
+{
+  # fixedHashesNix uses 'import from derivation' which does not parallelize well
+  # you should build newHashes first, before evaluating (and building) fixedHashesNix
+  newHashes = map computeHash (filter (fod: ! fod ? outputHash) fods);
+
+  fixedHashesNix = writeText "fixed-hashes.nix"
+  ''
+    {
+    ${lib.concatMapStrings hashLine fods}}
+  '';
+}