#26022 Add util::ResultPtr class

Introduces `util::ResultPtr`, a wrapper around `util::Result` tailored for pointer types like `std::unique_ptr`. It enables single dereferencing (`*res` and `res->member`) and adjusts boolean evaluation to check that the result succeeded and the underlying pointer is non-null. Call sites returning unique pointers in `LoadAddrman` and the wallet loader interfaces are converted to use the new type.

Problem: Wrapping pointers in `util::Result` requires awkward double-dereferencing (`**res` or `(*res)->member`) to access pointed-to members. Moreover, evaluating a `util::Result` in a boolean context returns true whenever an error is absent, even if the wrapped pointer is null, which risks misleading checks and null-pointer bugs (#26004).

Evidence of importance:

• Addresses issue #26004 ('util::Result has confusing interface for std::*_ptr T')
• Author description: 'Instead of needing to be deferenced twice with **result or (*result)->member, it only needs to be dereferenced once with *result or result->member. Also when it is used in a boolean context, instead of evaluating to true when there is no error and the pointer is null, it evaluates to false so it is straightforward to determine whether the result points to something.'

Scope: The branch includes the commit stack of base PR #25665 (+842/-199 across 19 files); only the top two commits specifically introduce and apply `util::ResultPtr`.

Risk of a mistake: low (wallet, other). A bug in pointer validity checks or dereferencing logic could cause wallet load or addrman initialization failures during startup.

Changed since the previous assessment: Rebased on top of updated base PR #25665, incorporating CI compiler flag adjustments (`-Wno-error=maybe-uninitialized`) and memory usage tests from the underlying stack.

Ready · Review #25665 first

Stacked on #25665; the base PR's changes are included in this diff.

Waiting on (from the thread read):

• author: response to l0rinc's question regarding whether boolean check is inverted 2026-07-23

Mild

objection that needs an answer has none yet (l0rinc)

Thread notes: Added rebase announcements by the author; l0rinc's objection regarding the boolean check remains open.

Objections, suggestions, and questions:

Participants:

• l0rinc (member, objection, 1 statements 2026-07-23 to 2026-07-23): asked whether a boolean check in src/wallet/interfaces.cpp was inverted

Depends on: #25665

Based on (shares commits with): #25665

Base for: #25722

263 lines under test/bench/ci.

• src/util/result.h +398/-63
• src/test/result_tests.cpp +239/-11
• src/node/chainstate.cpp +56/-39
• src/util/messages.h +52/-0
• src/init.cpp +24/-21
• src/util/messages.cpp +32/-0
• src/wallet/interfaces.cpp +9/-20
• src/node/chainstate.h +6/-22
• src/kernel/bitcoinkernel.cpp +7/-7
• src/test/util/setup_common.cpp +4/-4
• src/interfaces/wallet.h +3/-3
• src/qt/walletcontroller.cpp +3/-3
• src/wallet/wallet.cpp +2/-2
• ci/test/00_setup_env_win64.sh +2/-1
• ci/test/00_setup_env_native_previous_releases.sh +1/-1
• src/addrdb.cpp +1/-1
• src/addrdb.h +1/-1
• src/kernel/CMakeLists.txt +1/-0
• src/util/CMakeLists.txt +1/-0

The short text the ranking pass compares across PRs.

Introduces `util::ResultPtr`, a wrapper around `util::Result` for pointer-like types such as `std::unique_ptr`. It enables single dereference syntax (`*res`, `res->member`) and ensures contextual boolean checks evaluate to false if an error occurred or if the pointer is null. This addresses the confusing interface and null-pointer risks reported in #26004, updating call sites in `LoadAddrman` and wallet loader interfaces. Depends on base PR #25665.

P3 · cleanup (ranking pass: Moved down: pure error-handling ergonomics rank below correctness and performance work here, but kept ahead of its dependent #25722.)

Provides a safer, cleaner error-and-result pattern for pointer types across the codebase. It addresses issue #26004 where `util::Result` wrapping pointers required awkward double-dereferencing (`**res`) and avoided misleading boolean checks where null pointers evaluated to true.

Membership: Adds `util::ResultPtr` in src/util/result.h to improve result types handling pointers.

Factors: security/stability 1, bug 0, performance 0, user value 0, leverage 1