Invert project.nix dependency, simplify installation script

cachix · Oct 1, 2019 · 669b2f3 · 669b2f3
1 parent 2739673
commit 669b2f3
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Showing 5 changed files with 72 additions and 78 deletions.
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
@@ -1,5 +1,5 @@
 # DO NOT MODIFY
-# This file was generated by project.nix
+# This file was generated by nix-pre-commit-hooks
 {
   "repos": [
     {

diff --git a/modules/pre-commit.nix b/modules/pre-commit.nix
@@ -175,8 +175,6 @@ let
       [ $? -eq 0 ] && exit $exitcode
     '';
 
-  srcStr = toString ( config.root.origSrc or config.root );
-
   # TODO: provide a default pin that the user may override
   inherit (import (import ../nix/sources.nix).gitignore { inherit lib; })
     gitignoreSource
@@ -255,6 +253,16 @@ in {
           default = run;
         };
 
+      installationScript =
+        mkOption {
+          type = types.str;
+          description =
+            ''
+              A bash snippet that installs nix-pre-commit in the current directory
+            '';
+          readOnly = true;
+        };
+
       rootSrc =
         mkOption {
           type = types.package;
@@ -269,51 +277,39 @@ in {
     };
 
   config =
-    mkIf cfg.enable {
-
-      shell.packages = [ cfg.package ];
+    {
 
-      activation.hooks =
-        mkIf cfg.enableAutoInstall [
-          ''
-            export PATH=$PATH:${cfg.package}/bin
-            if ! type -t git >/dev/null; then
-              # This happens in pure shells, including lorri
-              echo 1>&2 "WARNING: nix-pre-commit-hooks: git command not found; skipping installation."
+      pre-commit.installationScript =
+        ''
+          export PATH=$PATH:${cfg.package}/bin
+          if ! type -t git >/dev/null; then
+            # This happens in pure shells, including lorri
+            echo 1>&2 "WARNING: nix-pre-commit-hooks: git command not found; skipping installation."
+          else
+            # Avoid filesystem churn. We may be watched!
+            # This prevents lorri from looping after every interactive shell command.
+            if readlink .pre-commit-hooks >/dev/null \
+              && [[ $(readlink .pre-commit-hooks) == ${hooks} ]]; then
+              echo 1>&2 "nix-pre-commit-hooks: hooks up to date"
             else
-              (
-                # We use srcStr to protect against installing pre-commit hooks
-                # in the wrong places such as for example ./. when invoking
-                #   nix-shell ../../other-project/shell.nix
-                cd ${lib.escapeShellArg srcStr} && {
-                  # Avoid filesystem churn. We may be watched!
-                  # This prevents lorri from looping after every interactive shell command.
-                  if readlink .pre-commit-hooks >/dev/null \
-                    && [[ $(readlink .pre-commit-hooks) == ${hooks} ]]; then
-                    echo 1>&2 "nix-pre-commit-hooks: hooks up to date"
-                  else
-                    echo 1>&2 "nix-pre-commit-hooks: updating" ${lib.escapeShellArg srcStr}
+              echo 1>&2 "nix-pre-commit-hooks: updating $PWD"
 
-                    [ -L .pre-commit-hooks ] && unlink .pre-commit-hooks
-                    ln -s ${hooks} .pre-commit-hooks
+              [ -L .pre-commit-hooks ] && unlink .pre-commit-hooks
+              ln -s ${hooks} .pre-commit-hooks
 
-                    # This can't be a symlink because its path is not constant,
-                    # thus can not be committed and is invisible to pre-commit.
-                    unlink .pre-commit-config.yaml
-                    { echo '# DO NOT MODIFY';
-                      echo '# This file was generated by project.nix';
-                      ${pkgs.jq}/bin/jq . <${configFile}
-                    } >.pre-commit-config.yaml
+              # This can't be a symlink because its path is not constant,
+              # thus can not be committed and is invisible to pre-commit.
+              unlink .pre-commit-config.yaml
+              { echo '# DO NOT MODIFY';
+                echo '# This file was generated by nix-pre-commit-hooks';
+                ${pkgs.jq}/bin/jq . <${configFile}
+              } >.pre-commit-config.yaml
 
-                    pre-commit install
-                    # this is needed as the hook repo configuration is cached
-                    pre-commit clean
-                  fi
-                }
-              )
+              pre-commit install
+              # this is needed as the hook repo configuration is cached
+              pre-commit clean
             fi
-          ''
-        ];
-
+          fi
+        '';
     };
 }
diff --git a/nix/project-module.nix b/nix/project-module.nix
@@ -0,0 +1,11 @@
+/*
+  This module is picked up by project.nix but is also used internally
+  to find these imported modules.
+ */
+{
+  imports =
+    [
+      ../modules/pre-commit.nix
+      ../modules/hooks.nix
+    ];
+}
diff --git a/nix/run.nix b/nix/run.nix
@@ -7,36 +7,35 @@
 let
   sources = import ./sources.nix;
 
-  # TODO upstream this and add tests to support this use case
-  project-nix-core =
-    map ( f: sources."project.nix" + ("/" + f) ) [
-      "modules/root.nix"
-      "modules/activation.nix"
-      "modules/shell.nix"
-      "modules/nixpkgs.nix"
-    ];
-
   project =
     lib.evalModules {
       modules =
-        project-nix-core ++ [
+        [
+          ./project-module.nix
           {
-            root = src;
-            nixpkgs.pkgs = pkgs;
-            pre-commit.tools = lib.mkDefault tools;
-            pre-commit.enable = true;
-            pre-commit.hooks = hooks;
+            options =
+              {
+                root =
+                  lib.mkOption {
+                    description = "Internal option";
+                    default = src;
+                    internal = true;
+                    readOnly = true;
+                    type = lib.types.unspecified;
+                  };
+              };
+            config =
+              {
+                _module.args.pkgs = pkgs;
+                pre-commit.hooks = hooks;
+                pre-commit.tools = lib.mkDefault tools;
+              };
           }
-          ../modules/pre-commit.nix
-          ../modules/hooks.nix
-      ];
+        ];
     };
-  inherit (project.config.shell.shell) shellHook activationHook;
+  inherit (project.config.pre-commit) installationScript;
 
 in
   project.config.pre-commit.run // {
-    shellHook = ''
-      activationHook=${lib.escapeShellArg activationHook}
-      ${shellHook}
-    '';
+    shellHook = installationScript;
   }
diff --git a/nix/sources.json b/nix/sources.json
@@ -118,17 +118,5 @@
         "type": "tarball",
         "url": "https://github.com/tweag/ormolu/archive/a7076c0f83e5c06ea9067b71171859fa2ba8afd9.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "project.nix": {
-        "branch": "pre-commit",
-        "description": "A configuration manager for your projects",
-        "homepage": null,
-        "owner": "hercules-ci",
-        "repo": "project.nix",
-        "rev": "ec17ac79904a296f358961ffcff7a13948c2b92e",
-        "sha256": "1gkb9k995ly53d5sxn5hr4lyzh57sq25j3i2cw8zva92g8x69gb5",
-        "type": "tarball",
-        "url": "https://github.com/hercules-ci/project.nix/archive/ec17ac79904a296f358961ffcff7a13948c2b92e.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }