this derivation will be built:
  /nix/store/fdaz9qxiyw2jfp4dshqz1nry3r436948-treefmt-check.drv
building '/nix/store/fdaz9qxiyw2jfp4dshqz1nry3r436948-treefmt-check.drv'
treefmt-check> treefmt v2.4.0traversed 916 files
treefmt-check> emitted 230 files for processing
treefmt-check> formatted 230 files (1 changed) in 795ms
treefmt-check>  M nix/packages/postgres.nix
treefmt-check> diff --git a/nix/packages/postgres.nix b/nix/packages/postgres.nix
treefmt-check> index d95acbc..90ff1ab 100644
treefmt-check> --- a/nix/packages/postgres.nix
treefmt-check> +++ b/nix/packages/postgres.nix
treefmt-check> @@ -253,13 +253,17 @@
treefmt-check>      in
treefmt-check>      {
treefmt-check>        packages = binPackages;
treefmt-check> -      legacyPackages = basePackages // slimPackages // cliPackages // {
treefmt-check> -        # DO NOT MERGE, TESTING: dummy package to exercise the version-diff CI job.
treefmt-check> -        version-diff-test-dummy = pkgs.writeTextFile {
treefmt-check> -          name = "version-diff-test-dummy-1.0.0";
treefmt-check> -          text = "testing drvpath-scoped version-diff workflow\n";
treefmt-check> -          destination = "/share/version-diff-test-dummy";
treefmt-check> +      legacyPackages =
treefmt-check> +        basePackages
treefmt-check> +        // slimPackages
treefmt-check> +        // cliPackages
treefmt-check> +        // {
treefmt-check> +          # DO NOT MERGE, TESTING: dummy package to exercise the version-diff CI job.
treefmt-check> +          version-diff-test-dummy = pkgs.writeTextFile {
treefmt-check> +            name = "version-diff-test-dummy-1.0.0";
treefmt-check> +            text = "testing drvpath-scoped version-diff workflow\n";
treefmt-check> +            destination = "/share/version-diff-test-dummy";
treefmt-check> +          };
treefmt-check>          };
treefmt-check> -      };
treefmt-check>      };
treefmt-check>  }
error: Cannot build '/nix/store/fdaz9qxiyw2jfp4dshqz1nry3r436948-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/z23ifawgi6ba40g93hrw1n36payaiq94-treefmt-check
       Last 25 log lines:
       > @@ -253,13 +253,17 @@
       >      in
       >      {
       >        packages = binPackages;
       > -      legacyPackages = basePackages // slimPackages // cliPackages // {
       > -        # DO NOT MERGE, TESTING: dummy package to exercise the version-diff CI job.
       > -        version-diff-test-dummy = pkgs.writeTextFile {
       > -          name = "version-diff-test-dummy-1.0.0";
       > -          text = "testing drvpath-scoped version-diff workflow\n";
       > -          destination = "/share/version-diff-test-dummy";
       > +      legacyPackages =
       > +        basePackages
       > +        // slimPackages
       > +        // cliPackages
       > +        // {
       > +          # DO NOT MERGE, TESTING: dummy package to exercise the version-diff CI job.
       > +          version-diff-test-dummy = pkgs.writeTextFile {
       > +            name = "version-diff-test-dummy-1.0.0";
       > +            text = "testing drvpath-scoped version-diff workflow\n";
       > +            destination = "/share/version-diff-test-dummy";
       > +          };
       >          };
       > -      };
       >      };
       >  }
       For full logs, run:
         nix log /nix/store/fdaz9qxiyw2jfp4dshqz1nry3r436948-treefmt-check.drv