ci: lint full C++ surface via ci-linux-tidy preset (#59)

* ci: lint full C++ surface via ci-linux-tidy preset

The clang-tidy gate used ci-linux-release-server, which (a) omits the diagram
tool + examples from compile_commands, so changes there were silently un-linted
despite the paths filter matching them, and (b) writes to build-server/, which
the gate's -path build/<preset> never finds — so the gate had no compile DB at
all.

Add a dedicated ci-linux-tidy preset (tests + server + json + yaml + diagram +
examples; fuzz stays clang-only) using the default build/<preset> dir, and point
the caller at it with apt-packages: graphviz for the diagram tool's link deps.
Re-pin clang-tidy-diff.yml to the SHA carrying the new apt-packages input.

* test: temporary clang-tidy canary in diagram-tool (revert before merge)

Deliberate bugprone-integer-division in a previously-uncovered diagram-tool file
to prove the ci-linux-tidy gate (a) configures the grpc+graphviz feature union
and (b) now lints diagram-tool C++. Reverted once the annotation is confirmed.

* ci: pin clang-tidy gate to x64-linux to reuse the warm vcpkg cache

The gate inherited the shared workflow's x64-linux-static triplet default, which
has no warm binary cache in this repo, so configure rebuilt grpc from source and
hit the 30-min job timeout. Pin to x64-linux (the repo's CI triplet) so the gate
restores the server-enabled lane's cache — identical closure, no clobber risk.

* Revert "test: temporary clang-tidy canary in diagram-tool"

Canary validated: ci-linux-tidy configured the grpc+graphviz union, built the
diagram tool, and the gate annotated tools/viz_core/format.cpp inline (advisory,
green). Removing it leaves only the preset + caller change.

Author: CameronBrooks11

.github/workflows/clang-tidy.yml

@@ -19,8 +19,18 @@ permissions:
 
 jobs:
   clang-tidy-diff:
-    # ci-linux-release-server enables server + json + yaml (the broadest single
-    # preset). The diagram-tool subdir (separate feature) is not covered here.
-    uses: anolishq/.github/.github/workflows/clang-tidy-diff.yml@36dd130dddbff472be8fc5e1c1e575e528c83e1b # clang-tidy-diff
+    # ci-linux-tidy is the max-coverage tidy preset: tests + server + json + yaml
+    # + diagram-tool + examples, so compile_commands covers every shipped Linux
+    # C++ target the paths filter matches (fuzz is clang/libFuzzer-only and stays
+    # out of this g++ gate). The diagram tool links graphviz, hence apt-packages.
+    # NB: it uses the default build/<preset> binaryDir — unlike ci-linux-release-
+    # server (build-server/), which the gate's -path build/<preset> can't find.
+    uses: anolishq/.github/.github/workflows/clang-tidy-diff.yml@bc822a0e1a1638789ecd912e3761283084fe914a # clang-tidy-diff
     with:
-      configure-preset: ci-linux-release-server
+      # x64-linux (not the gate's x64-linux-static default) so we reuse the warm
+      # vcpkg cache the server-enabled CI lane writes — its closure (grpc+protobuf
+      # +json+yaml+gtest) is exactly ci-linux-tidy's. With the static default the
+      # configure step rebuilt grpc from source cold and hit the 30-min timeout.
+      triplet: x64-linux
+      configure-preset: ci-linux-tidy
+      apt-packages: graphviz

CMakePresets.json

@@ -121,6 +121,15 @@
         "FLUXGRAPH_YAML_ENABLED": "ON"
       }
     },
+    {
+      "name": "ci-linux-tidy",
+      "inherits": "ci-linux-release-diagram",
+      "cacheVariables": {
+        "FLUXGRAPH_BUILD_SERVER": "ON",
+        "FLUXGRAPH_YAML_ENABLED": "ON",
+        "FLUXGRAPH_BUILD_EXAMPLES": "ON"
+      }
+    },
     {
       "name": "ci-tsan",
       "inherits": "ci-linux-release-server",
@@ -218,6 +227,10 @@
       "name": "ci-linux-release-server",
       "configurePreset": "ci-linux-release-server"
     },
+    {
+      "name": "ci-linux-tidy",
+      "configurePreset": "ci-linux-tidy"
+    },
     {
       "name": "ci-tsan",
       "configurePreset": "ci-tsan"