fetch and build grammars with nix in flake

This commit replaces the out-of-date builder in the flake which relied on submodules for fetching and the compiler for building. Now we disable fetching and building explicitly with the environment variable and then use builtins.fetchGit and a derivation mostly derived from upstream to compile the grammars. Anecdotally, this is still quite slow as builtins.fetchGit does not seem to do shallow clones. I'm not sure I see a way around it though without recording sha256s, which seems cumbersome.
rbino · Mar 10, 2022 · 37520f4 · 37520f4
1 parent b157c5a
commit 37520f4
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diff --git a/flake.nix b/flake.nix
@@ -33,26 +33,32 @@
         package = "helix";
       };
       overrides = {
-        crateOverrides = common: _: rec {
-          helix-term = prev: {
-            # disable fetching and building of tree-sitter grammars in the helix-term build.rs
-            HELIX_DISABLE_AUTO_GRAMMAR_BUILD = "1";
-            buildInputs = (prev.buildInputs or [ ]) ++ [ common.cCompiler.cc.lib ];
-            nativeBuildInputs = (prev.nativeBuildInputs or [ ]) ++ [ common.pkgs.makeWrapper ];
-            preConfigure = ''
-              ${prev.preConfigure}
-              rm -r helix-syntax/languages
-              ln -s ${helix}/helix-syntax/languages helix-syntax/languages
-              ln -s "$PWD/helix-syntax/languages" languages
-              mkdir -p runtime/grammars
-            '';
-            postInstall = ''
-              ${prev.postInstall or ""}
-              mkdir -p $out/lib
-              cp -r runtime $out/lib
-              wrapProgram "$out/bin/hx" --set HELIX_RUNTIME "$out/lib/runtime"
-            '';
-          };
+        crateOverrides = common: _: {
+          helix-term = prev:
+            let
+              inherit (common) pkgs;
+              grammars = pkgs.callPackage ./grammars.nix { };
+              runtimeDir = pkgs.runCommand "helix-runtime" { } ''
+                mkdir -p $out
+                ln -s ${common.root}/runtime/* $out
+                rm -r $out/grammars
+                ln -s ${grammars} $out/grammars
+              '';
+            in
+            {
+              # disable fetching and building of tree-sitter grammars in the helix-term build.rs
+              HELIX_DISABLE_AUTO_GRAMMAR_BUILD = "1";
+              # link languages and theme toml files since helix-term expects them (for tests)
+              preConfigure = "ln -s ${common.root}/{languages.toml,theme.toml,base16_theme.toml} ..";
+              buildInputs = (prev.buildInputs or [ ]) ++ [ common.cCompiler.cc.lib ];
+              nativeBuildInputs = [ pkgs.makeWrapper ];
+
+              postFixup = ''
+                if [ -f "$out/bin/hx" ]; then
+                  wrapProgram "$out/bin/hx" --set HELIX_RUNTIME "${runtimeDir}"
+                fi
+              '';
+            };
         };
         shell = common: prev: {
           packages = prev.packages ++ (with common.pkgs; [ lld_13 lldb cargo-tarpaulin cargo-flamegraph ]);

diff --git a/grammars.nix b/grammars.nix
@@ -0,0 +1,87 @@
+{ stdenv, lib, runCommand, yj }:
+let
+  # HACK: nix < 2.6 has a bug in the toml parser, so we convert to JSON
+  # before parsing
+  languages-json = runCommand "languages-toml-to-json" { } ''
+    ${yj}/bin/yj -t < ${./languages.toml} > $out
+  '';
+  languagesConfig =
+    builtins.fromJSON (builtins.readFile (builtins.toPath languages-json));
+  isGitGrammar = (grammar:
+    builtins.hasAttr "source" grammar && builtins.hasAttr "git" grammar.source
+    && builtins.hasAttr "rev" grammar.source);
+  gitGrammars = builtins.filter isGitGrammar languagesConfig.grammar;
+  buildGrammar = grammar:
+    let
+      source = builtins.fetchGit {
+        url = grammar.source.git;
+        rev = grammar.source.rev;
+        allRefs = true;
+      };
+    in stdenv.mkDerivation rec {
+      # see https://github.com/NixOS/nixpkgs/blob/fbdd1a7c0bc29af5325e0d7dd70e804a972eb465/pkgs/development/tools/parsing/tree-sitter/grammar.nix
+
+      pname = "helix-tree-sitter-${grammar.name}";
+      version = grammar.source.rev;
+
+      src = if builtins.hasAttr "subpath" grammar.source then
+        "${source}/${grammar.source.subpath}"
+      else
+        source;
+
+      dontUnpack = true;
+      dontConfigure = true;
+
+      FLAGS = [
+        "-I${src}/src"
+        "-g"
+        "-O3"
+        "-fPIC"
+        "-fno-exceptions"
+        "-Wl,-z,relro,-z,now"
+      ];
+
+      NAME = grammar.name;
+
+      buildPhase = ''
+        runHook preBuild
+
+        if [[ -e "$src/src/scanner.cc" ]]; then
+          $CXX -c "$src/src/scanner.cc" -o scanner.o $FLAGS
+        elif [[ -e "$src/src/scanner.c" ]]; then
+          $CC -c "$src/src/scanner.c" -o scanner.o $FLAGS
+        fi
+
+        $CC -c "$src/src/parser.c" -o parser.o $FLAGS
+        $CXX -shared -o $NAME.so *.o
+
+        ls -al
+
+        runHook postBuild
+      '';
+
+      installPhase = ''
+        runHook preInstall
+        mkdir $out
+        mv $NAME.so $out/
+        runHook postInstall
+      '';
+
+      # Strip failed on darwin: strip: error: symbols referenced by indirect symbol table entries that can't be stripped
+      fixupPhase = lib.optionalString stdenv.isLinux ''
+        runHook preFixup
+        $STRIP $out/$NAME.so
+        runHook postFixup
+      '';
+    };
+  builtGrammars = builtins.map (grammar: {
+    inherit (grammar) name;
+    artifact = buildGrammar grammar;
+  }) gitGrammars;
+  grammarLinks = builtins.map (grammar:
+    "ln -s ${grammar.artifact}/${grammar.name}.so $out/${grammar.name}.so")
+    builtGrammars;
+in runCommand "consolidated-helix-grammars" { } ''
+  mkdir -p $out
+  ${builtins.concatStringsSep "\n" grammarLinks}
+''