Merge bitcoin/bitcoin#28579: refactor: Remove redundant checks in compat/assumptions.h

fa1a384 Move compat.h include from system.h to system.cpp (MarcoFalke)
8888753 Move compat/assumptions.h include to one place that actually needs it (MarcoFalke)
7777411 Remove __cplusplus from compat/assumptions.h (MarcoFalke)
faa3d4f Remove duplicate NDEBUG check from compat/assumptions.h (MarcoFalke)

Pull request description:

  Generally, compile-time checks should be close to the code that use them. Especially, since `compat/assumptions.h` is only included in one place, where iwyu suggests to remove it.

  Fix all issues:
  * The `NDEBUG` check is used in `util/check`, so it is redundant in `compat/assumptions.h`.
  * The `__cplusplus` check is redundant with `doc/dependencies.md` (see commit message).
  * Add missing `// IWYU pragma: keep` to avoid removing the include by accident.

ACKs for top commit:
  achow101:
    ACK fa1a384
  TheCharlatan:
    re-ACK fa1a384
  theuni:
    ACK fa1a384

Tree-SHA512: f8b6db84be5d8844a2267345c0b1405fcbc39b8b5eeaa24db5b8412a74145fe44cf188b6b0c39cc2b062690ed37ca5b4662473484afe28dbec6469e79961389b

Author: achow101

src/common/system.cpp

@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2022 The Bitcoin Core developers
+// Copyright (c) 2009-present The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -12,6 +12,7 @@
 #ifndef WIN32
 #include <sys/stat.h>
 #else
+#include <compat/compat.h>
 #include <codecvt>
 #endif
 

src/common/system.h

@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2022 The Bitcoin Core developers
+// Copyright (c) 2009-present The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -10,11 +10,7 @@
 #include <config/bitcoin-config.h>
 #endif
 
-#include <compat/assumptions.h>
-#include <compat/compat.h>
-
-#include <set>
-#include <stdint.h>
+#include <cstdint>
 #include <string>
 
 // Application startup time (used for uptime calculation)

src/compat/assumptions.h

@@ -11,20 +11,6 @@
 #include <cstddef>
 #include <limits>
 
-// Assumption: We assume that the macro NDEBUG is not defined.
-// Example(s): We use assert(...) extensively with the assumption of it never
-//             being a noop at runtime.
-#if defined(NDEBUG)
-# error "Bitcoin cannot be compiled without assertions."
-#endif
-
-// Assumption: We assume a C++17 (ISO/IEC 14882:2017) compiler (minimum requirement).
-// Example(s): We assume the presence of C++17 features everywhere :-)
-// ISO Standard C++17 [cpp.predefined]p1:
-// "The name __cplusplus is defined to the value 201703L when compiling a C++
-//  translation unit."
-static_assert(__cplusplus >= 201703L, "C++17 standard assumed");
-
 // Assumption: We assume the floating-point types to fulfill the requirements of
 //             IEC 559 (IEEE 754) standard.
 // Example(s): Floating-point division by zero in ConnectBlock, CreateTransaction

src/net_processing.cpp

@@ -16,9 +16,9 @@
 #include <hash.h>
 #include <headerssync.h>
 #include <index/blockfilterindex.h>
+#include <kernel/chain.h>
 #include <kernel/mempool_entry.h>
 #include <logging.h>
-#include <kernel/chain.h>
 #include <merkleblock.h>
 #include <netbase.h>
 #include <netmessagemaker.h>
@@ -39,7 +39,7 @@
 #include <txmempool.h>
 #include <txorphanage.h>
 #include <txrequest.h>
-#include <util/check.h> // For NDEBUG compile time check
+#include <util/check.h>
 #include <util/strencodings.h>
 #include <util/trace.h>
 #include <validation.h>

src/serialize.h

@@ -7,7 +7,10 @@
 #define BITCOIN_SERIALIZE_H
 
 #include <attributes.h>
+#include <compat/assumptions.h> // IWYU pragma: keep
 #include <compat/endian.h>
+#include <prevector.h>
+#include <span.h>
 
 #include <algorithm>
 #include <cstdint>
@@ -18,13 +21,9 @@
 #include <memory>
 #include <set>
 #include <string>
-#include <string.h>
 #include <utility>
 #include <vector>
 
-#include <prevector.h>
-#include <span.h>
-
 /**
  * The maximum size of a serialized object in bytes or number of elements
  * (for eg vectors) when the size is encoded as CompactSize.

src/validation.cpp

@@ -45,7 +45,7 @@
 #include <txmempool.h>
 #include <uint256.h>
 #include <undo.h>
-#include <util/check.h> // For NDEBUG compile time check
+#include <util/check.h>
 #include <util/fs.h>
 #include <util/fs_helpers.h>
 #include <util/hasher.h>