Update to NixOS 26.05

.flake/pkgs/bencher-cli.nix

@@ -1,7 +1,7 @@
 { stdenv
 , lib
 , fetchurl
-, alsaLib
+, alsa-lib
 , openssl
 , zlib
 , pulseaudio

.flake/pkgs/cudnn.nix

@@ -0,0 +1,13 @@
+{ cudaPackages
+, fetchurl
+}:
+
+# Pin the latest cuDNN version with support for NVIDIA Pascal GPUs.
+cudaPackages.cudnn.overrideAttrs (finalAttrs: _: {
+  version = "9.10.2.21";
+
+  src = fetchurl {
+    url = "https://developer.download.nvidia.com/compute/cudnn/redist/cudnn/linux-x86_64/cudnn-linux-x86_64-${finalAttrs.version}_cuda12-archive.tar.xz";
+    hash = "sha256-0N78vExtrXEf9Mtm0lQDajAMkHGwfHtkGZqsq1NDE8E=";
+  };
+})

.flake/pkgs/fccf/default.nix

@@ -39,6 +39,7 @@ stdenv.mkDerivation rec {
   patches = [
     ./json-package-name.patch
     ./fix-argparse-include.patch
+    ./fix-cstdint-include.patch
   ];
 
   cmakeFlags = [

.flake/pkgs/fccf/fix-cstdint-include.patch

@@ -0,0 +1,10 @@
+diff --git a/source/sse2_strstr.cpp b/source/sse2_strstr.cpp
+index 44441ea..347cafd 100644
+--- a/source/sse2_strstr.cpp
++++ b/source/sse2_strstr.cpp
+@@ -1,4 +1,5 @@
+ #include <cassert>
++#include <cstdint>
+ #include <cstring>
+
+ #include <ctype.h>

.flake/pkgs/hpp2plantuml.nix

@@ -1,4 +1,9 @@
-{buildPythonPackage, fetchPypi}:
+{ buildPythonPackage
+, fetchPypi
+, jinja2
+, robotpy-cppheaderparser
+, sphinx
+}:
 
 buildPythonPackage rec {
   pname = "hpp2plantuml";
@@ -8,4 +13,16 @@ buildPythonPackage rec {
     inherit pname version format;
     sha256 = "sha256-PfTJmBypI21AAK3sMojygQfrhnRqcMmVCW4dxGfDfQg=";
   };
+
+  # argparse is part of the python 3 standard library, so there is no
+  # corresponding nixpkgs package to depend on.
+  pythonRemoveDeps = [ "argparse" ];
+
+  dependencies = [
+    jinja2
+    robotpy-cppheaderparser
+    sphinx
+  ];
+
+  pythonImportsCheck = [ "hpp2plantuml" ];
 }

.flake/pkgs/nixgl/default.nix

@@ -0,0 +1,18 @@
+{ applyPatches
+, pkgs
+, src
+}:
+
+# Need a not-yet-merged PR for nixGL compatibility with NixOS 26.05.
+#
+# This evaluates to nixGL's package set, not a derivation, so it belongs in a
+# let binding rather than in the flake's `packages` output.
+import
+  (applyPatches {
+    name = "nixGL-patched-source";
+    inherit src;
+    patches = [ ./drop-kernel-override.patch ];
+  })
+  {
+    inherit pkgs;
+  }

.flake/pkgs/nixgl/drop-kernel-override.patch

@@ -0,0 +1,16 @@
+`kernel` parameter is gone as of https://github.com/NixOS/nixpkgs/pull/498612
+
+Matching PR for nixGL in https://github.com/nix-community/nixGL/pull/223
+(among other things, not relevant to our use case)
+and has not been merged as of 2026-07-27.
+
+--- a/nixGL.nix
++++ b/nixGL.nix
+@@ -86,7 +86,6 @@
+
+       nvidiaLibsOnly = nvidiaDrivers.override {
+         libsOnly = true;
+-        kernel = null;
+       };
+
+       nixGLNvidiaBumblebee = writeExecutable {

.flake/pkgs/realm.nix

@@ -13,13 +13,13 @@ in
 
 stdenv.mkDerivation rec {
   pname = "realm";
-  version = "2026-02-24";
+  version = "2026-07-01";
 
   src = fetchFromGitHub {
     owner = "StanfordLegion";
     repo = "realm";
-    rev = "42f7484a80e0bdacaf47d9a758822f5327348dd0";
-    sha256 = "sha256-IHiokPmTjEV5df3fr1Xubuyt2N1CFI2fA7Q2TsbxS3Y=";
+    rev = "dba83452d4a211e3a0c0e5d4849c26ce7b56bba3";
+    sha256 = "sha256-dLGmUgupDX0dDErZbuP5ipj2Cwf+rOhVGC/+angRyBY=";
   };
 
   nativeBuildInputs = [

.flake/pkgs/robotpy-cppheaderparser.nix

@@ -0,0 +1,22 @@
+{ buildPythonPackage
+, fetchPypi
+, setuptools
+, ply
+}:
+
+buildPythonPackage rec {
+  pname = "robotpy-cppheaderparser";
+  version = "5.1.2";
+  pyproject = true;
+
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "sha256-FdNQs5NYtFzbH+E4r578zg5jLBtYgwoboboJihdSaYs=";
+  };
+
+  build-system = [ setuptools ];
+
+  dependencies = [ ply ];
+
+  pythonImportsCheck = [ "CppHeaderParser" ];
+}

.github/workflows/tests.yml

@@ -43,11 +43,40 @@ jobs:
         run: |
           proj check cpu-ci
 
+      - name: Generate code coverage
+        run: |
+          # A toolchain mismatch between the instrumentation and libgcov makes
+          # every test abort profiling without writing anything, which would
+          # otherwise surface as a silent 0% report rather than a failure.
+          gcda_count="$(find build/coverage -name '*.gcda' | wc -l)"
+          echo "found $gcda_count .gcda files"
+          if [ "$gcda_count" -eq 0 ]; then
+            echo "::error::no coverage data was produced by the test run" >&2
+            exit 1
+          fi
+          # lcov 2.x treats several classes of gcov disagreement as hard
+          # errors; gcc emits them routinely for templates, so downgrade them.
+          lcov_opts=(
+            --rc geninfo_unexecuted_blocks=1
+            --ignore-errors "inconsistent,mismatch,unused,negative,source,empty"
+            -j "$(nproc)"
+          )
+          lcov "${lcov_opts[@]}" --capture --directory build/coverage --output-file coverage-all.info
+          # Paths recorded by geninfo are absolute, so anchor on $PWD rather
+          # than a bare 'lib/*'.
+          lcov "${lcov_opts[@]}" --extract coverage-all.info "$PWD/lib/*" --output-file coverage-lib.info
+          lcov "${lcov_opts[@]}" --remove coverage-lib.info '*.dtg.h' '*.dtg.cc' --output-file main_coverage.info
+          lcov "${lcov_opts[@]}" --list main_coverage.info
+
       - name: Upload code coverage
         uses: codecov/codecov-action@v4
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
-          file: main_coverage.info
+          files: main_coverage.info
+          # We hand codecov the one report we generated above; without these it
+          # searches the tree and runs its gcov plugin over the whole build.
+          disable_search: true
+          plugins: noop
           flags: unittests
           name: codecov-umbrella
           fail_ci_if_error: false

contributing.dox

@@ -189,7 +189,7 @@ We actively welcome your pull requests. Note that we may already be working on t
 The steps for getting changes merged into %FlexFlow are relatively standard:
 
 1. [Fork the repo](https://github.com/flexflow/flexflow-train/fork) and either create a new branch based on `master`, or just modify `master` directly.
-2. If you've added code that should be tested, add tests. The process for adding tests for code under `lib` is documented [here](./lib/README.md#tests). Adding tests for other parts of the code is currently undocumented, so you will \ref contributing-contact-us "contact us" for information on how to do it.
+2. If you've added code that should be tested, add tests. The process for adding tests is currently undocumented, so you will \ref contributing-contact-us "contact us" for information on how to do it.
 3. Ensure the code builds (i.e., run `proj build`).
 4. Ensure the test suite passes (i.e., run `proj test`).
 5. Format the code (i.e., run `proj format`).