build(nix): refactor, dont pass git hash and tag

flake.nix

@@ -31,30 +31,6 @@
           pkgs = common.pkgs;
           lib = pkgs.lib;
 
-          gitLfsCheckFile = ./assets/voxygen/background/bg_main.jpg;
-          utils = import ./nix/utils.nix {inherit pkgs;};
-
-          sourceInfo =
-            if inputs.self.sourceInfo ? rev
-            then
-              inputs.self.sourceInfo
-              // {
-                # Tag would have to be set manually for stable releases flake
-                # because there's currently no way to get the tag via the interface.
-                # tag = v0.9.0;
-              }
-            else (throw "Can't get revision because the git tree is dirty");
-
-          prettyRev = with sourceInfo;
-            builtins.substring 0 8 rev
-            + "/"
-            + utils.dateTimeFormat lastModified;
-
-          tag =
-            if sourceInfo ? tag
-            then sourceInfo.tag
-            else "";
-
           configMoldLinker = ''
             cat >>$CARGO_HOME/config.toml <<EOF
               [target.x86_64-unknown-linux-gnu]
@@ -90,10 +66,12 @@
           veloren-common = oldAttrs: {
             # Disable `git-lfs` check here since we check it ourselves
             # We have to include the command output here, otherwise Nix won't run it
-            DISABLE_GIT_LFS_CHECK = utils.isGitLfsSetup gitLfsCheckFile;
+            DISABLE_GIT_LFS_CHECK = true;
-            # Declare env values here so that `common/build.rs` sees them
+            # We don't add in any information here because otherwise anything
-            NIX_GIT_HASH = prettyRev;
+            # that depends on common will be recompiled. Ideally we should have
-            NIX_GIT_TAG = tag;
+            # a way to pass these in a wrapper, at runtime, rather than build time.
+            NIX_GIT_HASH = "";
+            NIX_GIT_TAG = "";
           };
           veloren-voxygen-deps = oldAttrs: {
             doCheck = false;
@@ -181,6 +159,24 @@
       assets = pkgs.runCommand "veloren-assets" {} ''
         mkdir $out
         ln -sf ${./assets} $out/assets
+        # check if LFS was setup properly
+        checkFile="$out/assets/voxygen/background/bg_main.jpg"
+        result="$(${pkgs.file}/bin/file --mime-type $checkFile)"
+        if [ "$result" = "$checkFile: image/jpeg" ]; then
+          echo "Git LFS seems to be setup properly."
+        else
+          echo "
+            Git Large File Storage (git-lfs) has not been set up correctly.
+            Most common reasons:
+              - git-lfs was not installed before cloning this repository.
+              - This repository was not cloned from the primary GitLab mirror.
+              - The GitHub mirror does not support LFS.
+            See the book at https://book.veloren.net/ for details.
+            Run 'nix-shell -p git git-lfs --run \"git lfs install --local && git lfs fetch && git lfs checkout\"'
+            or 'nix shell nixpkgs#git-lfs nixpkgs#git -c sh -c \"git lfs install --local && git lfs fetch && git lfs checkout\"'.
+          "
+          false
+        fi
       '';
       wrapped =
         pkgs.runCommand "${old.name}-wrapped"

nix/dateTimeFormat.nix

@@ -0,0 +1,21 @@
+t: let
+  rem = x: y: x - x / y * y;
+  days = t / 86400;
+  secondsInDay = rem t 86400;
+  hours = secondsInDay / 3600;
+  minutes = (rem secondsInDay 3600) / 60;
+
+  # Courtesy of https://stackoverflow.com/a/32158604.
+  z = days + 719468;
+  era = (if z >= 0 then z else z - 146096) / 146097;
+  doe = z - era * 146097;
+  yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
+  y = yoe + era * 400;
+  doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+  mp = (5 * doy + 2) / 153;
+  d = doy - (153 * mp + 2) / 5 + 1;
+  m = mp + (if mp < 10 then 3 else -9);
+  y' = y + (if m <= 2 then 1 else 0);
+
+  pad = s: if builtins.stringLength s < 2 then "0" + s else s;
+in "${toString y'}-${pad (toString m)}-${pad (toString d)}-${pad (toString hours)}:${pad (toString minutes)}"

nix/utils.nix

@@ -1,66 +0,0 @@
-{pkgs}: {
-  isGitLfsSetup = checkFile: let
-    gitLfsCheckOutput = builtins.readFile (pkgs.runCommand "gitLfsCheck" {} ''
-      result="$(${pkgs.file}/bin/file --mime-type ${checkFile})"
-      (if [ "$result" = "${checkFile}: image/jpeg" ]; then printf "0"; else printf "1"; fi) > $out
-    '');
-  in
-    if gitLfsCheckOutput == "0"
-    then true
-    else
-      throw ''
-        Git Large File Storage (`git-lfs`) has not been set up correctly.
-        Most common reasons:
-          - `git-lfs` was not installed before cloning this repository.
-          - This repository was not cloned from the primary GitLab mirror.
-          - The GitHub mirror does not support LFS.
-        See the book at https://book.veloren.net/ for details.
-        Run `nix-shell -p git git-lfs --run "git lfs install --local && git lfs fetch && git lfs checkout"`
-        or `nix shell nixpkgs#git-lfs nixpkgs#git -c sh -c "git lfs install --local && git lfs fetch && git lfs checkout"`.
-      '';
-
-  # Format number of seconds in the Unix epoch as %Y-%m-%d-%H:%M.
-  dateTimeFormat = t: let
-    rem = x: y: x - x / y * y;
-    days = t / 86400;
-    secondsInDay = rem t 86400;
-    hours = secondsInDay / 3600;
-    minutes = (rem secondsInDay 3600) / 60;
-    seconds = rem t 60;
-
-    # Courtesy of https://stackoverflow.com/a/32158604.
-    z = days + 719468;
-    era =
-      (
-        if z >= 0
-        then z
-        else z - 146096
-      )
-      / 146097;
-    doe = z - era * 146097;
-    yoe = (doe - doe / 1460 + doe / 36524 - doe / 146096) / 365;
-    y = yoe + era * 400;
-    doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
-    mp = (5 * doy + 2) / 153;
-    d = doy - (153 * mp + 2) / 5 + 1;
-    m =
-      mp
-      + (
-        if mp < 10
-        then 3
-        else -9
-      );
-    y' =
-      y
-      + (
-        if m <= 2
-        then 1
-        else 0
-      );
-
-    pad = s:
-      if builtins.stringLength s < 2
-      then "0" + s
-      else s;
-  in "${toString y'}-${pad (toString m)}-${pad (toString d)}-${pad (toString hours)}:${pad (toString minutes)}";
-}