Warnings in tests are errors

[eddyashton]

These changes are pristine, unseen, unsullied by human eyes. They exist beyond a quality assessment. I wrote this as a joke and then scrolled down a little and realised this include diffs from a totally different PR! Oh well, I'll deal with that tomorrow.

[Copilot]

Pull request overview

This PR aims to make warnings in CCF’s C++ unit tests fail the build (treat warnings as errors) by enabling stricter compiler warning flags for unit-test targets and then updating a broad set of tests (plus a few supporting headers) to eliminate common warning sources (unused variables, signed/unsigned mismatches, unsafe strerror, VLAs, etc).

Changes:

• Enable warning/error compile flags for unit test targets via CMake (add_warning_checks).
• Introduce and adopt a thread-safe ccf::nonstd::strerror() wrapper to replace concurrency-unsafe std::strerror.
• Refactor many tests to avoid warnings (unused variables, narrowing, shadowing, unused captures, designated init completeness, etc).

Custom instructions used:

• .github/copilot-instructions.md
• .github/instructions/reviewing.instructions.md

Reviewed changes

Copilot reviewed 46 out of 46 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/tls/test/main.cpp	Replace strerror, remove VLAs, tighten test buffer handling
src/tasks/test/fan_in_tasks.cpp	Fix signed/unsigned loop variable warnings
src/tasks/test/demo/clients.h	Fix signed/unsigned / implicit conversion warnings
src/tasks/test/basic_tasks.cpp	Remove unused WaitPoint variables
src/snapshots/snapshot_manager.h	Use thread-safe ccf::nonstd::strerror in error paths
src/pal/test/snp_attestation_validation.cpp	Fill designated initializers to silence warnings
src/node/test/snapshotter.cpp	Update aggregate init / naming to avoid warnings
src/node/test/snapshot.cpp	Rename to avoid shadowing/unused warnings
src/node/test/node_info_json.cpp	Expand initializer to match updated struct layout
src/node/test/network_identity_subsystem.cpp	Silence nodiscard/unused-result warnings in throw checks
src/node/test/historical_queries.cpp	Remove unused locals/lambdas; rename loop vars
src/node/test/encryptor.cpp	Assert commit result rather than unused variable
src/node/test/channels.cpp	Remove unused locals; adjust switches/loop vars
src/node/rpc/test/tx_status_test.cpp	Remove unused constants
src/node/rpc/test/node_frontend_test.cpp	Rename locals; adjust status expectations (test logic)
src/node/rpc/test/frontend_test.cpp	Remove unused lambda captures; rename locals
src/node/rpc/test/frontend_test_infra.h	Rename locals to avoid shadowing/unreferenced warnings
src/kv/test/kv_test.cpp	Remove unused locals; rename variables; fix switch completeness
src/kv/test/kv_snapshot.cpp	Remove unused locals; rename constants/handles; reduce unused vars
src/kv/test/kv_dynamic_tables.cpp	Remove unused handle variable
src/kv/test/kv_contention.cpp	Rename loop variables to avoid shadowing and warnings
src/indexing/test/lfs.cpp	Fix signed/unsigned loops; remove unused constant
src/indexing/test/indexing.cpp	Remove unused constants/aliases
src/host/test/ledger.cpp	Add [[maybe_unused]], fix loop index types, rename locals
src/host/tcp.h	Replace std::strerror with ccf::nonstd::strerror
src/host/ledger.h	Replace std::strerror with ccf::nonstd::strerror
src/endpoints/test/endpoint_registry.cpp	Rename locals to avoid unused/shadowing warnings
src/ds/test/work_beacon.cpp	Fix loop index types to avoid sign warnings
src/ds/test/serializer.cpp	Mark unused helper; rename locals to avoid shadowing
src/ds/test/ring_buffer.cpp	Fix loop types; remove unused captures; fix implicit conversions
src/ds/test/oversized.cpp	Rename variables to avoid shadowing/unused warnings
src/ds/test/nonstd.cpp	Rename locals to avoid shadowing/unused warnings
src/ds/test/messaging.cpp	Fix incorrect unconditional REQUIRE; remove unused lambda/vars
src/ds/test/map_test.cpp	Rename locals to avoid shadowing; fix index warnings
src/ds/test/json_schema.cpp	Avoid reference-to-temporary warnings / adjust loop var
src/ds/test/dl_list.cpp	Fully initialize aggregate to avoid missing-field warnings
src/ds/system.h	Replace strerror with ccf::nonstd::strerror
src/ds/files.h	Replace strerror with ccf::nonstd::strerror in file helpers
src/crypto/test/crypto.cpp	Rename locals, fix loop index types, avoid shadowing
src/consensus/aft/test/main.cpp	Remove redundant locals; fix loop/index conversions; simplify lambda captures
src/consensus/aft/test/logging_stub.h	Add virtual destructors; mark unused; avoid unused-result warnings
src/consensus/aft/test/committable_suffix.cpp	Fix implicit conversion warnings from rand() result
include/ccf/pal/snp_ioctl6.h	Replace strerror with nonstd::strerror
include/ccf/ds/nonstd.h	Add thread-safe strerror wrapper implementation
include/ccf/ds/contiguous_set.h	Fix narrowing/sign conversion warnings; remove unused local
cmake/common.cmake	Apply add_warning_checks() to unit-test targets