build(nix): filter src to reduce useless rebuilds

This in particular speeds up the dev/run/debug cycle for writing more tests. Without this, the actual bcachefs-tools package will be rebuilt by Nix all the time because of changes to files that are tracked by git. Even when it's changes in parts that aren't relevant to that package build such as `checks/*`. Signed-off-by: Thomas Mühlbacher <[email protected]>
koverstreet · Jun 18, 2024 · a7ec4a9 · a7ec4a9
1 parent 34cafd2
commit a7ec4a9
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Showing 2 changed files with 29 additions and 1 deletion.
diff --git a/flake.lock b/flake.lock
diff --git a/flake.nix b/flake.nix
@@ -11,6 +11,8 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
+    nix-filter.url = "github:numtide/nix-filter";
+
     crane = {
       url = "github:ipetkov/crane";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -33,6 +35,7 @@
       nixpkgs,
       flake-parts,
       treefmt-nix,
+      nix-filter,
       fenix,
       crane,
       ...
@@ -64,6 +67,8 @@
           cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
           rustfmtToml = builtins.fromTOML (builtins.readFile ./rustfmt.toml);
 
+          filter = nix-filter.lib;
+
           craneLib = crane.mkLib pkgs;
 
           rev = self.shortRev or self.dirtyShortRev or (substring 0 8 self.lastModifiedDate);
@@ -74,7 +79,14 @@
 
           commonArgs = {
             inherit version;
-            src = self;
+            src = filter {
+              root = self;
+              exclude = [
+                "checks"
+                "doc"
+                "tests"
+              ];
+            };
 
             env = {
               PKG_CONFIG_SYSTEMD_SYSTEMDSYSTEMUNITDIR = "${placeholder "out"}/lib/systemd/system";