test(meta): filter LoweredCodeUtils' benign JET-scan warnings

JET.test_package collects method signatures via Revise/LoweredCodeUtils
without calling anything. For keyword-argument functor methods, Julia
compiles a hidden var"#_#N" body function that LoweredCodeUtils cannot
statically attribute to its parent method, so it emits a "skipping callee
... UndefRefError()" warning before moving on and continuing the scan
unaffected (10 such warnings from HamiltonianVectorField's variable_costate
kwarg methods). It is a collector limitation, not a JET finding.

Wraps the JET testset in a logger that filters that specific message
(prefix + emitting module), so any other warning from LoweredCodeUtils
still surfaces normally. Logging added to the test target (a stdlib, but
CTBase's strict Pkg.test sandbox needs it declared explicitly, same as the
existing Markdown/Test entries).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: ocots

Project.toml

@@ -32,6 +32,7 @@ DifferentiationInterface = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 JET = "c3a54625-cd67-489e-a8e7-0a5a0ff4e31b"
+Logging = "56ddb016-857b-54e1-b83d-db4d58db5568"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 MarkdownAST = "d0879d2d-cac2-40c8-9cee-1863dc0c7391"
 Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
@@ -46,6 +47,7 @@ test = [
     "Documenter",
     "ForwardDiff",
     "JET",
+    "Logging",
     "Markdown",
     "MarkdownAST",
     "Plots",
@@ -62,6 +64,7 @@ DocStringExtensions = "0.9"
 Documenter = "1"
 ForwardDiff = "0.10, 1"
 JET = "0.11"
+Logging = "1"
 Markdown = "1"
 MarkdownAST = "0.1"
 Plots = "1"

test/suite/meta/test_code_quality.jl

@@ -4,10 +4,57 @@ using Test: Test
 using Aqua: Aqua
 using JET: JET
 using CTBase: CTBase
+using Logging: Logging
 
 const VERBOSE = isdefined(Main, :TestData) ? Main.TestData.VERBOSE : true
 const SHOWTIMING = isdefined(Main, :TestData) ? Main.TestData.SHOWTIMING : true
 
+# ==============================================================================
+# Filter LoweredCodeUtils' benign "skipping callee ... UndefRefError()" warnings
+# ==============================================================================
+#
+# JET.test_package collects method signatures via Revise/LoweredCodeUtils without
+# calling anything. For keyword-argument functor methods (a callable struct with a
+# `; kwarg=default` in its call signature), Julia compiles a hidden body function
+# named `var"#_#N"`; LoweredCodeUtils cannot statically attribute that hidden body
+# to its parent method and emits a `@warn "skipping callee ..." ` before moving on.
+# It is a collector limitation, not a JET finding — the flagged body is simply
+# excluded from the static scan; everything else (including its runtime behavior,
+# covered by the normal test suite) is unaffected.
+#
+# Filtered precisely by message prefix + emitting module, so any other, unrelated
+# warning from LoweredCodeUtils still surfaces normally.
+struct _SkipBenignLoweredCodeUtilsWarnings <: Logging.AbstractLogger
+    logger::Logging.AbstractLogger
+end
+
+Logging.min_enabled_level(l::_SkipBenignLoweredCodeUtilsWarnings) =
+    Logging.min_enabled_level(l.logger)
+
+Logging.shouldlog(l::_SkipBenignLoweredCodeUtilsWarnings, level, _module, group, id) =
+    Logging.shouldlog(l.logger, level, _module, group, id)
+
+function Logging.handle_message(
+    l::_SkipBenignLoweredCodeUtilsWarnings,
+    level,
+    message,
+    _module,
+    group,
+    id,
+    file,
+    line;
+    kwargs...,
+)
+    if level == Logging.Warn &&
+        nameof(_module) === :LoweredCodeUtils &&
+        startswith(string(message), "skipping callee")
+        return nothing
+    end
+    return Logging.handle_message(
+        l.logger, level, message, _module, group, id, file, line; kwargs...
+    )
+end
+
 function test_code_quality()
     Test.@testset verbose = VERBOSE showtiming = SHOWTIMING "Code quality" begin
         Test.@testset verbose = VERBOSE showtiming = SHOWTIMING "Aqua" begin
@@ -23,7 +70,11 @@ function test_code_quality()
         end
 
         Test.@testset "JET" begin
-            JET.test_package(CTBase; target_modules=(CTBase,))
+            Logging.with_logger(
+                _SkipBenignLoweredCodeUtilsWarnings(Logging.current_logger())
+            ) do
+                JET.test_package(CTBase; target_modules=(CTBase,))
+            end
         end
 
         # Test.@testset "JuliaFormatter" begin