From f87776bd7c3cc67de6155ed8c9fd32ebda4bfdb0 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 11:49:53 -0700
Subject: [PATCH 01/16] pkgs/top-level/metrics.nix: use stdenvNoCC.mkDerivation
 instead of runCommand

---
 pkgs/top-level/metrics.nix | 43 +++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 15 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index c6ff0f349313..5670dda5383c 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -1,25 +1,35 @@
 { nixpkgs, pkgs }:
 
-with pkgs;
+let
+  inherit (pkgs) lib stdenvNoCC;
+in
+
+stdenvNoCC.mkDerivation {
+  name = "nixpkgs-metrics";
+
+  nativeBuildInputs = map lib.getBin [
+    pkgs.nix
+    pkgs.time
+    pkgs.jq
+  ];
+
+  # see https://github.com/NixOS/nixpkgs/issues/52436
+  #requiredSystemFeatures = [ "benchmark" ]; # dedicated `t2a` machine, by @vcunat
+
+  unpackPhase = ''
+    runHook preUnpack
 
-runCommand "nixpkgs-metrics"
-  {
-    nativeBuildInputs =
-      with pkgs.lib;
-      map getBin [
-        nix
-        time
-        jq
-      ];
-    # see https://github.com/NixOS/nixpkgs/issues/52436
-    #requiredSystemFeatures = [ "benchmark" ]; # dedicated `t2a` machine, by @vcunat
-  }
-  ''
     export NIX_STORE_DIR=$TMPDIR/store
     export NIX_STATE_DIR=$TMPDIR/state
     export NIX_PAGER=
     nix-store --init
 
+    runHook postUnpack
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
     mkdir -p $out/nix-support
     touch $out/nix-support/hydra-build-products
 
@@ -83,4 +93,7 @@ runCommand "nixpkgs-metrics"
 
     lines=$(find ${nixpkgs} -name "*.nix" -type f | xargs cat | wc -l)
     echo "loc $lines" >> $out/nix-support/hydra-metrics
-  ''
+
+    runHook postInstall
+  '';
+}

From c3f0ef37ebf21bfea5c17a7ef7d53afc39f711bc Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 12:00:32 -0700
Subject: [PATCH 02/16] pkgs/top-level/metrics.nix: add meta explaining this
 file

---
 pkgs/top-level/metrics.nix | 81 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 5670dda5383c..d2a755043aec 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -96,4 +96,85 @@ stdenvNoCC.mkDerivation {
 
     runHook postInstall
   '';
+
+  meta = {
+    description = "Metrics tracked by Hydra about Nixpkgs";
+    homepage = "https://hydra.nixos.org/job/nixpkgs/trunk/metrics";
+    longDescription = ''
+      View the metrics for Nixpkgs evaluation over time at these URLs.
+
+      These are all produced from running `nix` with `NIX_SHOW_STATS=1`.
+      See `EvalState::printStatistics` in the Nix source code for the implementation.
+      None of these metrics are inherently meaningful on their own.
+      Exercise caution in interpreting them as "bad" or "good".
+
+      # Total repository statistics
+
+      - [Lines of code in Nixpkgs](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/loc)
+      - [Count of broken packages using `nix-env -qa`](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaCountBroken)
+      - [Count of packages using `nix-env -qa`](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaCount)
+
+      # Statistics about representative commands
+
+      These are statistics gathered by running commands against Nixpkgs.
+
+      | Name | Command |
+      |------|---------|
+      | `nix-env.qaAggressive` | `nix-env -f ${nixpkgs} -qa` |
+      | `nix-env.qaDrvAggressive` | `nix-env -f ${nixpkgs} -qa --drv-path --meta --xml` |
+      | `nix-env.qaDrv` | `nix-env -f ${nixpkgs} -qa --drv-path --meta --xml` |
+      | `nix-env.qa` | `nix-env -f ${nixpkgs} -qa` |
+      | `nixos.kde` | `nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.kde.x86_64-linux --show-trace` |
+      | `nixos.lapp` | `nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.lapp.x86_64-linux --show-trace` |
+      | `nixos.smallContainer` | `nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.smallContainer.x86_64-linux --show-trace`|
+
+      ## Allocations performed (in bytes)
+
+      This counts `envs.bytes`, `list.bytes`, `values.bytes`, and `sets.bytes` from the Nix statistics.
+
+      - [nix-env.qa.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.allocations)
+      - [nix-env.qaAggressive.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.allocations)
+      - [nix-env.qaDrv.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.allocations)
+      - [nix-env.qaDrvAggressive.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.allocations)
+      - [nixos.kde.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.allocations)
+      - [nixos.lapp.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.allocations)
+      - [nixos.smallContainer.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.allocations)
+
+      ## Maximum resident size (in number of KiB)
+
+      This counts `maxresident` KiB (`%M`) from the `time` command on Linux.
+
+      - [nix-env.qa.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.maxresident)
+      - [nix-env.qaAggressive.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.maxresident)
+      - [nix-env.qaDrv.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.maxresident)
+      - [nix-env.qaDrvAggressive.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.maxresident)
+      - [nixos.kde.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.maxresident)
+      - [nixos.lapp.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.maxresident)
+      - [nixos.smallContainer.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.maxresident)
+
+      ## Time taken (in seconds)
+
+      This counts `cpuTime` as reported in the Nix statistics. On Linux, this resolves to [`getrusage(RUSAGE_SELF)`](https://man7.org/linux/man-pages/man2/getrusage.2.html).
+
+      - [nix-env.qa.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.time)
+      - [nix-env.qaAggressive.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.time)
+      - [nix-env.qaDrv.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.time)
+      - [nix-env.qaDrvAggressive.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.time)
+      - [nixos.kde.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.time)
+      - [nixos.lapp.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.time)
+      - [nixos.smallContainer.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.time)
+
+      ## Number of values
+
+      This counts the total number of values allocated in Nix (see `EvalState::allocValue` in the Nix source code).
+
+      - [nix-env.qa.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.values)
+      - [nix-env.qaAggressive.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.values)
+      - [nix-env.qaDrv.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.values)
+      - [nix-env.qaDrvAggressive.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.values)
+      - [nixos.kde.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.values)
+      - [nixos.lapp.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.values)
+      - [nixos.smallContainer.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.values)
+    '';
+  };
 }

From a34bbb6b9cd5f511fb5d5cff7d2ceb12d927cffb Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 12:14:54 -0700
Subject: [PATCH 03/16] pkgs/top-level/metrics.nix: tidy up variables and
 quoting

We also allow the lines to be unbroken.
---
 pkgs/top-level/metrics.nix | 53 +++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index d2a755043aec..9b80d3d300e4 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -40,49 +40,48 @@ stdenvNoCC.mkDerivation {
       echo "running $@"
 
       case "$name" in
-        # Redirect stdout to /dev/null to avoid hitting "Output Limit
-        # Exceeded" on Hydra.
+        # Redirect stdout to /dev/null to avoid hitting "Output Limit Exceeded" on Hydra.
         nix-env.qaDrv|nix-env.qaDrvAggressive)
           NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH=stats-nix time -o stats-time "$@" >/dev/null ;;
         *)
           NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH=stats-nix time -o stats-time "$@" ;;
       esac
 
-      cat stats-nix; echo; cat stats-time; echo
+      # Show the Nix statistics and the `time` statistics.
+      cat stats-nix
+      echo
+      cat stats-time
+      echo
 
-      x=$(jq '.cpuTime' < stats-nix)
-      [[ -n $x ]] || exit 1
-      echo "$name.time $x s" >> $out/nix-support/hydra-metrics
+      cpuTime="$(jq '.cpuTime' < stats-nix)"
+      [[ -n $cpuTime ]] || exit 1
+      echo "$name.time $cpuTime s" >> $out/nix-support/hydra-metrics
 
-      x=$(sed -e 's/.* \([0-9]\+\)maxresident.*/\1/ ; t ; d' < stats-time)
-      [[ -n $x ]] || exit 1
-      echo "$name.maxresident $x KiB" >> $out/nix-support/hydra-metrics
+      maxresident="$(sed -e 's/.* \([0-9]\+\)maxresident.*/\1/ ; t ; d' < stats-time)"
+      [[ -n $maxresident ]] || exit 1
+      echo "$name.maxresident $maxresident KiB" >> $out/nix-support/hydra-metrics
 
-      # nix-2.2 also outputs .symbols.bytes but that wasn't summed originally
-      # https://github.com/NixOS/nix/pull/2392/files#diff-8e6ba8c21672fc1a5f6f606e1e101c74L1762
-      x=$(jq '[.envs,.list,.values,.sets] | map(.bytes) | add' < stats-nix)
-      [[ -n $x ]] || exit 1
-      echo "$name.allocations $x B" >> $out/nix-support/hydra-metrics
+      # Nix also outputs `.symbols.bytes` but since that wasn't summed originally, we don't count it here.
+      allocations="$(jq '[.envs,.list,.values,.sets] | map(.bytes) | add' < stats-nix)"
+      [[ -n $allocations ]] || exit 1
+      echo "$name.allocations $allocations B" >> $out/nix-support/hydra-metrics
 
-      x=$(jq '.values.number' < stats-nix)
-      [[ -n $x ]] || exit 1
-      echo "$name.values $x" >> $out/nix-support/hydra-metrics
+      values="$(jq '.values.number' < stats-nix)"
+      [[ -n $values ]] || exit 1
+      echo "$name.values $values" >> $out/nix-support/hydra-metrics
     }
 
-    run nixos.smallContainer nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix \
-      -A closures.smallContainer.x86_64-linux --show-trace
-    run nixos.kde nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix \
-      -A closures.kde.x86_64-linux --show-trace
-    run nixos.lapp nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix \
-      -A closures.lapp.x86_64-linux --show-trace
+    run nixos.smallContainer nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.smallContainer.x86_64-linux --show-trace
+    run nixos.kde nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.kde.x86_64-linux --show-trace
+    run nixos.lapp nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.lapp.x86_64-linux --show-trace
     run nix-env.qa nix-env -f ${nixpkgs} -qa
     run nix-env.qaDrv nix-env -f ${nixpkgs} -qa --drv-path --meta --xml
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
-    num=$(nix-env -f ${nixpkgs} -qa | wc -l)
+    num="$(nix-env -f ${nixpkgs} -qa | wc -l)"
     echo "nix-env.qaCount $num" >> $out/nix-support/hydra-metrics
-    qaCountDrv=$(nix-env -f ${nixpkgs} -qa --drv-path | wc -l)
-    num=$((num - $qaCountDrv))
+    qaCountDrv="$(nix-env -f ${nixpkgs} -qa --drv-path | wc -l)"
+    num="$((num - $qaCountDrv))"
     echo "nix-env.qaCountBroken $num" >> $out/nix-support/hydra-metrics
 
     # TODO: this has been ignored for some time
@@ -91,7 +90,7 @@ stdenvNoCC.mkDerivation {
     run nix-env.qaAggressive nix-env -f ${nixpkgs} -qa
     run nix-env.qaDrvAggressive nix-env -f ${nixpkgs} -qa --drv-path --meta --xml
 
-    lines=$(find ${nixpkgs} -name "*.nix" -type f | xargs cat | wc -l)
+    lines="$(find ${nixpkgs} -name "*.nix" -type f | xargs cat | wc -l)"
     echo "loc $lines" >> $out/nix-support/hydra-metrics
 
     runHook postInstall

From 29db1d32be1964eefd223a974f733f261f32ec55 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 12:21:52 -0700
Subject: [PATCH 04/16] pkgs/top-level/metrics.nix: use __structuredAttrs

---
 pkgs/top-level/metrics.nix | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 9b80d3d300e4..f1eff8e4c9ab 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -7,6 +7,10 @@ in
 stdenvNoCC.mkDerivation {
   name = "nixpkgs-metrics";
 
+  # Use structured attrs to pass in relevant information.
+  __structuredAttrs = true;
+  inherit nixpkgs;
+
   nativeBuildInputs = map lib.getBin [
     pkgs.nix
     pkgs.time
@@ -30,6 +34,8 @@ stdenvNoCC.mkDerivation {
   installPhase = ''
     runHook preInstall
 
+    release="$nixpkgs/nixos/release.nix"
+
     mkdir -p $out/nix-support
     touch $out/nix-support/hydra-build-products
 
@@ -71,26 +77,26 @@ stdenvNoCC.mkDerivation {
       echo "$name.values $values" >> $out/nix-support/hydra-metrics
     }
 
-    run nixos.smallContainer nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.smallContainer.x86_64-linux --show-trace
-    run nixos.kde nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.kde.x86_64-linux --show-trace
-    run nixos.lapp nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.lapp.x86_64-linux --show-trace
-    run nix-env.qa nix-env -f ${nixpkgs} -qa
-    run nix-env.qaDrv nix-env -f ${nixpkgs} -qa --drv-path --meta --xml
+    run nixos.smallContainer nix-instantiate --dry-run "$release" -A closures.smallContainer.x86_64-linux --show-trace
+    run nixos.kde nix-instantiate --dry-run "$release" -A closures.kde.x86_64-linux --show-trace
+    run nixos.lapp nix-instantiate --dry-run "$release" -A closures.lapp.x86_64-linux --show-trace
+    run nix-env.qa nix-env -f "$nixpkgs" -qa
+    run nix-env.qaDrv nix-env -f "$nixpkgs" -qa --drv-path --meta --xml
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
-    num="$(nix-env -f ${nixpkgs} -qa | wc -l)"
+    num="$(nix-env -f "$nixpkgs" -qa | wc -l)"
     echo "nix-env.qaCount $num" >> $out/nix-support/hydra-metrics
-    qaCountDrv="$(nix-env -f ${nixpkgs} -qa --drv-path | wc -l)"
+    qaCountDrv="$(nix-env -f "$nixpkgs" -qa --drv-path | wc -l)"
     num="$((num - $qaCountDrv))"
     echo "nix-env.qaCountBroken $num" >> $out/nix-support/hydra-metrics
 
     # TODO: this has been ignored for some time
     # GC Warning: Bad initial heap size 128k - ignoring it.
     #export GC_INITIAL_HEAP_SIZE=128k
-    run nix-env.qaAggressive nix-env -f ${nixpkgs} -qa
-    run nix-env.qaDrvAggressive nix-env -f ${nixpkgs} -qa --drv-path --meta --xml
+    run nix-env.qaAggressive nix-env -f "$nixpkgs" -qa
+    run nix-env.qaDrvAggressive nix-env -f "$nixpkgs" -qa --drv-path --meta --xml
 
-    lines="$(find ${nixpkgs} -name "*.nix" -type f | xargs cat | wc -l)"
+    lines="$(find "$nixpkgs" -name "*.nix" -type f | xargs cat | wc -l)"
     echo "loc $lines" >> $out/nix-support/hydra-metrics
 
     runHook postInstall

From b2331161b3aeb84a9a0be008cb1547cb3d34cb56 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 12:28:15 -0700
Subject: [PATCH 05/16] pkgs/top-level/metrics.nix: remove the aggressive
 variants

They've been the same as the non-aggressive variants since Jan 13, 2019 (61b8c03a78caa)
---
 pkgs/top-level/metrics.nix | 18 +-----------------
 1 file changed, 1 insertion(+), 17 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index f1eff8e4c9ab..702dcea29d27 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -47,7 +47,7 @@ stdenvNoCC.mkDerivation {
 
       case "$name" in
         # Redirect stdout to /dev/null to avoid hitting "Output Limit Exceeded" on Hydra.
-        nix-env.qaDrv|nix-env.qaDrvAggressive)
+        nix-env.qaDrv)
           NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH=stats-nix time -o stats-time "$@" >/dev/null ;;
         *)
           NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH=stats-nix time -o stats-time "$@" ;;
@@ -90,12 +90,6 @@ stdenvNoCC.mkDerivation {
     num="$((num - $qaCountDrv))"
     echo "nix-env.qaCountBroken $num" >> $out/nix-support/hydra-metrics
 
-    # TODO: this has been ignored for some time
-    # GC Warning: Bad initial heap size 128k - ignoring it.
-    #export GC_INITIAL_HEAP_SIZE=128k
-    run nix-env.qaAggressive nix-env -f "$nixpkgs" -qa
-    run nix-env.qaDrvAggressive nix-env -f "$nixpkgs" -qa --drv-path --meta --xml
-
     lines="$(find "$nixpkgs" -name "*.nix" -type f | xargs cat | wc -l)"
     echo "loc $lines" >> $out/nix-support/hydra-metrics
 
@@ -125,8 +119,6 @@ stdenvNoCC.mkDerivation {
 
       | Name | Command |
       |------|---------|
-      | `nix-env.qaAggressive` | `nix-env -f ${nixpkgs} -qa` |
-      | `nix-env.qaDrvAggressive` | `nix-env -f ${nixpkgs} -qa --drv-path --meta --xml` |
       | `nix-env.qaDrv` | `nix-env -f ${nixpkgs} -qa --drv-path --meta --xml` |
       | `nix-env.qa` | `nix-env -f ${nixpkgs} -qa` |
       | `nixos.kde` | `nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.kde.x86_64-linux --show-trace` |
@@ -138,9 +130,7 @@ stdenvNoCC.mkDerivation {
       This counts `envs.bytes`, `list.bytes`, `values.bytes`, and `sets.bytes` from the Nix statistics.
 
       - [nix-env.qa.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.allocations)
-      - [nix-env.qaAggressive.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.allocations)
       - [nix-env.qaDrv.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.allocations)
-      - [nix-env.qaDrvAggressive.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.allocations)
       - [nixos.kde.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.allocations)
       - [nixos.lapp.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.allocations)
       - [nixos.smallContainer.allocations](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.allocations)
@@ -150,9 +140,7 @@ stdenvNoCC.mkDerivation {
       This counts `maxresident` KiB (`%M`) from the `time` command on Linux.
 
       - [nix-env.qa.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.maxresident)
-      - [nix-env.qaAggressive.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.maxresident)
       - [nix-env.qaDrv.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.maxresident)
-      - [nix-env.qaDrvAggressive.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.maxresident)
       - [nixos.kde.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.maxresident)
       - [nixos.lapp.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.maxresident)
       - [nixos.smallContainer.maxresident](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.maxresident)
@@ -162,9 +150,7 @@ stdenvNoCC.mkDerivation {
       This counts `cpuTime` as reported in the Nix statistics. On Linux, this resolves to [`getrusage(RUSAGE_SELF)`](https://man7.org/linux/man-pages/man2/getrusage.2.html).
 
       - [nix-env.qa.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.time)
-      - [nix-env.qaAggressive.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.time)
       - [nix-env.qaDrv.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.time)
-      - [nix-env.qaDrvAggressive.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.time)
       - [nixos.kde.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.time)
       - [nixos.lapp.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.time)
       - [nixos.smallContainer.time](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.time)
@@ -174,9 +160,7 @@ stdenvNoCC.mkDerivation {
       This counts the total number of values allocated in Nix (see `EvalState::allocValue` in the Nix source code).
 
       - [nix-env.qa.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qa.values)
-      - [nix-env.qaAggressive.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaAggressive.values)
       - [nix-env.qaDrv.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrv.values)
-      - [nix-env.qaDrvAggressive.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nix-env.qaDrvAggressive.values)
       - [nixos.kde.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.kde.values)
       - [nixos.lapp.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.lapp.values)
       - [nixos.smallContainer.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.values)

From 94f1da567e4717c81fc28195a6eb301e720303b6 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 12:49:26 -0700
Subject: [PATCH 06/16] pkgs/top-level/metrics.nix: convince the time command
 to output JSON

Also, name the JSON files with the .json extension and the name of the run being produced.
---
 pkgs/top-level/metrics.nix | 43 +++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 702dcea29d27..ba5de46f40ad 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -44,35 +44,37 @@ stdenvNoCC.mkDerivation {
       shift
 
       echo "running $@"
+      local nix_stats="$name-nix-stats.json"
+      local time_stats="$name-time-stats.json"
 
       case "$name" in
         # Redirect stdout to /dev/null to avoid hitting "Output Limit Exceeded" on Hydra.
         nix-env.qaDrv)
-          NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH=stats-nix time -o stats-time "$@" >/dev/null ;;
+          NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" time -o "$time_stats" "$@" >/dev/null ;;
         *)
-          NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH=stats-nix time -o stats-time "$@" ;;
+          NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" time -o "$time_stats" "$@" ;;
       esac
 
       # Show the Nix statistics and the `time` statistics.
-      cat stats-nix
+      cat "$nix_stats"
       echo
-      cat stats-time
+      cat "$time_stats"
       echo
 
-      cpuTime="$(jq '.cpuTime' < stats-nix)"
+      cpuTime="$(jq '.cpuTime' < "$nix_stats")"
       [[ -n $cpuTime ]] || exit 1
       echo "$name.time $cpuTime s" >> $out/nix-support/hydra-metrics
 
-      maxresident="$(sed -e 's/.* \([0-9]\+\)maxresident.*/\1/ ; t ; d' < stats-time)"
+      maxresident="$(jq '.max_resident_set_kb' < "$time_stats")"
       [[ -n $maxresident ]] || exit 1
       echo "$name.maxresident $maxresident KiB" >> $out/nix-support/hydra-metrics
 
       # Nix also outputs `.symbols.bytes` but since that wasn't summed originally, we don't count it here.
-      allocations="$(jq '[.envs,.list,.values,.sets] | map(.bytes) | add' < stats-nix)"
+      allocations="$(jq '[.envs,.list,.values,.sets] | map(.bytes) | add' < "$nix_stats")"
       [[ -n $allocations ]] || exit 1
       echo "$name.allocations $allocations B" >> $out/nix-support/hydra-metrics
 
-      values="$(jq '.values.number' < stats-nix)"
+      values="$(jq '.values.number' < "$nix_stats")"
       [[ -n $values ]] || exit 1
       echo "$name.values $values" >> $out/nix-support/hydra-metrics
     }
@@ -166,4 +168,29 @@ stdenvNoCC.mkDerivation {
       - [nixos.smallContainer.values](https://hydra.nixos.org/job/nixpkgs/trunk/metrics/metric/nixos.smallContainer.values)
     '';
   };
+
+  # Convince `time` to output in JSON
+  env.TIME = builtins.toJSON {
+    real_time = "%e";
+    user_time = "%U";
+    sys_time = "%S";
+    cpu_percent = "%P";
+    max_resident_set_kb = "%M";
+    avg_resident_set_kb = "%t";
+    avg_total_mem_kb = "%K";
+    avg_data_kb = "%D";
+    avg_stack_kb = "%p";
+    avg_unshared_data_kb = "%X";
+    avg_shared_text_kb = "%Z";
+    page_faults_major = "%F";
+    page_faults_minor = "%R";
+    swaps = "%W";
+    context_switches_voluntary = "%c";
+    context_switches_involuntary = "%w";
+    io_reads = "%I";
+    io_writes = "%O";
+    signals_received = "%k";
+    exit_status = "%x";
+    command = "%C";
+  };
 }

From b9519e2c0af72fe953c48cfa8e941d558219cfa2 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 13:04:37 -0700
Subject: [PATCH 07/16] pkgs/top-level/metrics.nix: log out the statistics
 using jq with a header

---
 pkgs/top-level/metrics.nix | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index ba5de46f40ad..6bd2be765950 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -56,9 +56,11 @@ stdenvNoCC.mkDerivation {
       esac
 
       # Show the Nix statistics and the `time` statistics.
-      cat "$nix_stats"
+      echo "Nix statistics for $@"
+      jq . "$nix_stats"
       echo
-      cat "$time_stats"
+      echo "Time statistics for $@"
+      jq . "$time_stats"
       echo
 
       cpuTime="$(jq '.cpuTime' < "$nix_stats")"

From e35ab56228ac9027e54c3eae9267fab48aaccd95 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 13:13:24 -0700
Subject: [PATCH 08/16] pkgs/top-level/metrics.nix: use the eval-system
 parameter to target a specific system

---
 pkgs/top-level/metrics.nix | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 6bd2be765950..29d66e2c5da8 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -2,6 +2,7 @@
 
 let
   inherit (pkgs) lib stdenvNoCC;
+  evalSystem = "x86_64-linux";
 in
 
 stdenvNoCC.mkDerivation {
@@ -9,7 +10,7 @@ stdenvNoCC.mkDerivation {
 
   # Use structured attrs to pass in relevant information.
   __structuredAttrs = true;
-  inherit nixpkgs;
+  inherit evalSystem nixpkgs;
 
   nativeBuildInputs = map lib.getBin [
     pkgs.nix
@@ -81,16 +82,16 @@ stdenvNoCC.mkDerivation {
       echo "$name.values $values" >> $out/nix-support/hydra-metrics
     }
 
-    run nixos.smallContainer nix-instantiate --dry-run "$release" -A closures.smallContainer.x86_64-linux --show-trace
-    run nixos.kde nix-instantiate --dry-run "$release" -A closures.kde.x86_64-linux --show-trace
-    run nixos.lapp nix-instantiate --dry-run "$release" -A closures.lapp.x86_64-linux --show-trace
-    run nix-env.qa nix-env -f "$nixpkgs" -qa
-    run nix-env.qaDrv nix-env -f "$nixpkgs" -qa --drv-path --meta --xml
+    run nixos.smallContainer nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.smallContainer.x86_64-linux --show-trace
+    run nixos.kde nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.kde.x86_64-linux --show-trace
+    run nixos.lapp nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.lapp.x86_64-linux --show-trace
+    run nix-env.qa nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa
+    run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --xml
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
-    num="$(nix-env -f "$nixpkgs" -qa | wc -l)"
+    num="$(nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa | wc -l)"
     echo "nix-env.qaCount $num" >> $out/nix-support/hydra-metrics
-    qaCountDrv="$(nix-env -f "$nixpkgs" -qa --drv-path | wc -l)"
+    qaCountDrv="$(nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path | wc -l)"
     num="$((num - $qaCountDrv))"
     echo "nix-env.qaCountBroken $num" >> $out/nix-support/hydra-metrics
 

From 146c6b9aadc712723370be6ecee8d28fc8f60331 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 15:48:37 -0700
Subject: [PATCH 09/16] pkgs/top-level/metrics.nix: use json, not XML

It's testing the same thing, and it's useful to have the JSON output.
---
 pkgs/top-level/metrics.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 29d66e2c5da8..14ed1092e9ee 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -86,7 +86,7 @@ stdenvNoCC.mkDerivation {
     run nixos.kde nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.kde.x86_64-linux --show-trace
     run nixos.lapp nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.lapp.x86_64-linux --show-trace
     run nix-env.qa nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa
-    run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --xml
+    run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --json
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
     num="$(nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa | wc -l)"
@@ -124,7 +124,7 @@ stdenvNoCC.mkDerivation {
 
       | Name | Command |
       |------|---------|
-      | `nix-env.qaDrv` | `nix-env -f ${nixpkgs} -qa --drv-path --meta --xml` |
+      | `nix-env.qaDrv` | `nix-env -f ${nixpkgs} -qa --drv-path --meta --json` |
       | `nix-env.qa` | `nix-env -f ${nixpkgs} -qa` |
       | `nixos.kde` | `nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.kde.x86_64-linux --show-trace` |
       | `nixos.lapp` | `nix-instantiate --dry-run ${nixpkgs}/nixos/release.nix -A closures.lapp.x86_64-linux --show-trace` |

From dfd90bf4c07b6eb3d101190c2ad2369c92ea52d5 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 13:15:47 -0700
Subject: [PATCH 10/16] pkgs/top-level/metrics.nix: just run nix-env -qa once

If we save the output, we can use it later with a little `jq`.
---
 pkgs/top-level/metrics.nix | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 14ed1092e9ee..fe1ddb0304cb 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -45,16 +45,11 @@ stdenvNoCC.mkDerivation {
       shift
 
       echo "running $@"
+      local output="$name.out"
       local nix_stats="$name-nix-stats.json"
       local time_stats="$name-time-stats.json"
 
-      case "$name" in
-        # Redirect stdout to /dev/null to avoid hitting "Output Limit Exceeded" on Hydra.
-        nix-env.qaDrv)
-          NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" time -o "$time_stats" "$@" >/dev/null ;;
-        *)
-          NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" time -o "$time_stats" "$@" ;;
-      esac
+      NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" time -o "$time_stats" "$@" > "$output"
 
       # Show the Nix statistics and the `time` statistics.
       echo "Nix statistics for $@"
@@ -89,11 +84,11 @@ stdenvNoCC.mkDerivation {
     run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --json
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
-    num="$(nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa | wc -l)"
+    num="$(wc -l < nix-env.qa.out)"
     echo "nix-env.qaCount $num" >> $out/nix-support/hydra-metrics
-    qaCountDrv="$(nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path | wc -l)"
-    num="$((num - $qaCountDrv))"
-    echo "nix-env.qaCountBroken $num" >> $out/nix-support/hydra-metrics
+    qaCountDrv="$(jq -r 'reduce .[].drvPath as $d (0; .+1)' < nix-env.qaDrv.out)"
+    numBroken="$((num - $qaCountDrv))"
+    echo "nix-env.qaCountBroken $numBroken" >> $out/nix-support/hydra-metrics
 
     lines="$(find "$nixpkgs" -name "*.nix" -type f | xargs cat | wc -l)"
     echo "loc $lines" >> $out/nix-support/hydra-metrics

From 251dff3a3e2a057cb7c3f8e46e15e1d95211c012 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Fri, 12 Sep 2025 15:25:06 -0700
Subject: [PATCH 11/16] pkgs/top-level/metrics.nix: save the raw files,
 compressing the output

---
 pkgs/top-level/metrics.nix | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index fe1ddb0304cb..e8ace0e84806 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -12,6 +12,11 @@ stdenvNoCC.mkDerivation {
   __structuredAttrs = true;
   inherit evalSystem nixpkgs;
 
+  outputs = [
+    "out"
+    "raw"
+  ];
+
   nativeBuildInputs = map lib.getBin [
     pkgs.nix
     pkgs.time
@@ -45,11 +50,13 @@ stdenvNoCC.mkDerivation {
       shift
 
       echo "running $@"
-      local output="$name.out"
-      local nix_stats="$name-nix-stats.json"
-      local time_stats="$name-time-stats.json"
 
-      NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" time -o "$time_stats" "$@" > "$output"
+      mkdir -p "$raw/$name"
+      local output="$raw/$name/output"
+      local nix_stats="$raw/$name/nix-stats.json"
+      local time_stats="$raw/$name/time-stats.json"
+
+      NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" command time -o "$time_stats" -- "$@" > "$output"
 
       # Show the Nix statistics and the `time` statistics.
       echo "Nix statistics for $@"
@@ -84,15 +91,18 @@ stdenvNoCC.mkDerivation {
     run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --json
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
-    num="$(wc -l < nix-env.qa.out)"
+    num="$(wc -l < $raw/nix-env.qa/output)"
     echo "nix-env.qaCount $num" >> $out/nix-support/hydra-metrics
-    qaCountDrv="$(jq -r 'reduce .[].drvPath as $d (0; .+1)' < nix-env.qaDrv.out)"
+    qaCountDrv="$(jq -r 'reduce .[].drvPath as $d (0; .+1)' $raw/nix-env.qaDrv/output)"
     numBroken="$((num - $qaCountDrv))"
     echo "nix-env.qaCountBroken $numBroken" >> $out/nix-support/hydra-metrics
 
     lines="$(find "$nixpkgs" -name "*.nix" -type f | xargs cat | wc -l)"
     echo "loc $lines" >> $out/nix-support/hydra-metrics
 
+    # Compress the raw output
+    xz -v $raw/*/output
+
     runHook postInstall
   '';
 

From 4973d53405faece1e5394cc9616fca610641d117 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Sat, 13 Sep 2025 05:29:34 -0700
Subject: [PATCH 12/16] pkgs/top-level/metrics.nix: use the latest Nix version,
 just like CI

---
 pkgs/top-level/metrics.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index e8ace0e84806..26ef31c4a1d8 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -18,7 +18,7 @@ stdenvNoCC.mkDerivation {
   ];
 
   nativeBuildInputs = map lib.getBin [
-    pkgs.nix
+    pkgs.nixVersions.latest
     pkgs.time
     pkgs.jq
   ];

From 8ac12754cecbfffadeb97178a32584f9342df04b Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Sat, 13 Sep 2025 05:47:22 -0700
Subject: [PATCH 13/16] pkgs/top-level/metrics.nix: turn off aliases in the
 evaluation

This mirrors `ci/eval` and also prevents many warnings from being logged.
---
 pkgs/top-level/metrics.nix | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 26ef31c4a1d8..fe9437572e93 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -201,4 +201,11 @@ stdenvNoCC.mkDerivation {
     exit_status = "%x";
     command = "%C";
   };
+
+  # Don't allow aliases anywhere in Nixpkgs for the metrics.
+  env.NIXPKGS_CONFIG = builtins.toFile "nixpkgs-config.nix" ''
+    {
+      allowAliases = false;
+    }
+  '';
 }

From fda7cefcdbd5e50052dfd3bf9b97ae5cc32d8cf9 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Sat, 13 Sep 2025 05:56:26 -0700
Subject: [PATCH 14/16] pkgs/top-level/metrics.nix: pass --no-gc-warning so
 that no spew about --add-root shows up

---
 pkgs/top-level/metrics.nix | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index fe9437572e93..8073666f7bd9 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -84,9 +84,9 @@ stdenvNoCC.mkDerivation {
       echo "$name.values $values" >> $out/nix-support/hydra-metrics
     }
 
-    run nixos.smallContainer nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.smallContainer.x86_64-linux --show-trace
-    run nixos.kde nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.kde.x86_64-linux --show-trace
-    run nixos.lapp nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.lapp.x86_64-linux --show-trace
+    run nixos.smallContainer nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.smallContainer.x86_64-linux --show-trace --no-gc-warning
+    run nixos.kde nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.kde.x86_64-linux --show-trace --no-gc-warning
+    run nixos.lapp nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.lapp.x86_64-linux --show-trace --no-gc-warning
     run nix-env.qa nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa
     run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --json
 

From 32c68bb46e8d51f5833830750af8bbb078299949 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Tue, 16 Sep 2025 05:43:25 -0700
Subject: [PATCH 15/16] pkgs/top-level/metrics.nix: use the configure, build,
 and install phases

Per CR feedback, this is better than unpack and install with build jammed into install.
---
 pkgs/top-level/metrics.nix | 55 +++++++++++++++++++++++---------------
 1 file changed, 33 insertions(+), 22 deletions(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index 8073666f7bd9..ee36532d5c41 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -26,35 +26,35 @@ stdenvNoCC.mkDerivation {
   # see https://github.com/NixOS/nixpkgs/issues/52436
   #requiredSystemFeatures = [ "benchmark" ]; # dedicated `t2a` machine, by @vcunat
 
-  unpackPhase = ''
-    runHook preUnpack
+  # Required because this derivation doesn't have a `src`.
+  dontUnpack = true;
+
+  configurePhase = ''
+    runHook preConfigure
 
     export NIX_STORE_DIR=$TMPDIR/store
     export NIX_STATE_DIR=$TMPDIR/state
     export NIX_PAGER=
     nix-store --init
 
-    runHook postUnpack
+    runHook postConfigure
   '';
 
-  installPhase = ''
-    runHook preInstall
+  buildPhase = ''
+    runHook preBuild
 
     release="$nixpkgs/nixos/release.nix"
 
-    mkdir -p $out/nix-support
-    touch $out/nix-support/hydra-build-products
-
     run() {
       local name="$1"
       shift
 
       echo "running $@"
 
-      mkdir -p "$raw/$name"
-      local output="$raw/$name/output"
-      local nix_stats="$raw/$name/nix-stats.json"
-      local time_stats="$raw/$name/time-stats.json"
+      mkdir -p "metrics/$name"
+      local output="metrics/$name/output"
+      local nix_stats="metrics/$name/nix-stats.json"
+      local time_stats="metrics/$name/time-stats.json"
 
       NIX_SHOW_STATS=1 NIX_SHOW_STATS_PATH="$nix_stats" command time -o "$time_stats" -- "$@" > "$output"
 
@@ -68,20 +68,20 @@ stdenvNoCC.mkDerivation {
 
       cpuTime="$(jq '.cpuTime' < "$nix_stats")"
       [[ -n $cpuTime ]] || exit 1
-      echo "$name.time $cpuTime s" >> $out/nix-support/hydra-metrics
+      echo "$name.time $cpuTime s" >> hydra-metrics
 
       maxresident="$(jq '.max_resident_set_kb' < "$time_stats")"
       [[ -n $maxresident ]] || exit 1
-      echo "$name.maxresident $maxresident KiB" >> $out/nix-support/hydra-metrics
+      echo "$name.maxresident $maxresident KiB" >> hydra-metrics
 
       # Nix also outputs `.symbols.bytes` but since that wasn't summed originally, we don't count it here.
       allocations="$(jq '[.envs,.list,.values,.sets] | map(.bytes) | add' < "$nix_stats")"
       [[ -n $allocations ]] || exit 1
-      echo "$name.allocations $allocations B" >> $out/nix-support/hydra-metrics
+      echo "$name.allocations $allocations B" >> hydra-metrics
 
       values="$(jq '.values.number' < "$nix_stats")"
       [[ -n $values ]] || exit 1
-      echo "$name.values $values" >> $out/nix-support/hydra-metrics
+      echo "$name.values $values" >> hydra-metrics
     }
 
     run nixos.smallContainer nix-instantiate --option eval-system "$evalSystem" --dry-run "$release" -A closures.smallContainer.x86_64-linux --show-trace --no-gc-warning
@@ -91,16 +91,27 @@ stdenvNoCC.mkDerivation {
     run nix-env.qaDrv nix-env --option eval-system "$evalSystem" -f "$nixpkgs" -qa --drv-path --meta --json
 
     # It's slightly unclear which of the set to track: qaCount, qaCountDrv, qaCountBroken.
-    num="$(wc -l < $raw/nix-env.qa/output)"
-    echo "nix-env.qaCount $num" >> $out/nix-support/hydra-metrics
-    qaCountDrv="$(jq -r 'reduce .[].drvPath as $d (0; .+1)' $raw/nix-env.qaDrv/output)"
+    num="$(wc -l < metrics/nix-env.qa/output)"
+    echo "nix-env.qaCount $num" >> hydra-metrics
+    qaCountDrv="$(jq -r 'reduce .[].drvPath as $d (0; .+1)' metrics/nix-env.qaDrv/output)"
     numBroken="$((num - $qaCountDrv))"
-    echo "nix-env.qaCountBroken $numBroken" >> $out/nix-support/hydra-metrics
+    echo "nix-env.qaCountBroken $numBroken" >> hydra-metrics
 
     lines="$(find "$nixpkgs" -name "*.nix" -type f | xargs cat | wc -l)"
-    echo "loc $lines" >> $out/nix-support/hydra-metrics
+    echo "loc $lines" >> hydra-metrics
 
-    # Compress the raw output
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out/nix-support
+    touch $out/nix-support/hydra-build-products
+    mv hydra-metrics $out/nix-support/hydra-metrics
+
+    # Save and compress the raw output
+    mv metrics $raw
     xz -v $raw/*/output
 
     runHook postInstall

From 79feab6cff53917a2fd40be55547faf68ea0eee5 Mon Sep 17 00:00:00 2001
From: Philip Taron <philip.taron@gmail.com>
Date: Tue, 16 Sep 2025 05:48:31 -0700
Subject: [PATCH 16/16] pkgs/top-level/metrics.nix: use -print0 to insulate us
 from spaces in find

---
 pkgs/top-level/metrics.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/top-level/metrics.nix b/pkgs/top-level/metrics.nix
index ee36532d5c41..c6380b74a667 100644
--- a/pkgs/top-level/metrics.nix
+++ b/pkgs/top-level/metrics.nix
@@ -97,7 +97,7 @@ stdenvNoCC.mkDerivation {
     numBroken="$((num - $qaCountDrv))"
     echo "nix-env.qaCountBroken $numBroken" >> hydra-metrics
 
-    lines="$(find "$nixpkgs" -name "*.nix" -type f | xargs cat | wc -l)"
+    lines="$(find "$nixpkgs" -name "*.nix" -type f -print0 | xargs -0 cat | wc -l)"
     echo "loc $lines" >> hydra-metrics
 
     runHook postBuild