Don't make "in" parameters look like "out"/"in-out" parameters: pass by ref to const instead of ref to non-const #20581

practicalswift · 2020-12-06T00:30:51Z

Don't make "in" parameters look like "out"/"in-out" parameters: pass by ref to const instead of ref to non-const.

…by ref to const instead of ref to non-const

DrahtBot · 2020-12-06T03:36:56Z

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Conflicts

Reviewers, this pull request conflicts with the following ones:

RPC: Show fee in results for signrawtransaction* for segwit inputs #18479 (RPC: Show fee in results for signrawtransaction* for segwit inputs by luke-jr)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

DrahtBot · 2020-12-06T10:14:40Z

🕵️ @sipa @fjahr have been requested to review this pull request as specified in the REVIEWERS file.

maflcko · 2020-12-06T10:30:29Z

cr ACK 12dcdaa

hebasto

ACK 12dcdaa, I have reviewed the code and it looks OK, I agree it can be merged.

All findings are made by a cool static analyzer, aren't they?

practicalswift · 2020-12-06T11:56:23Z

All findings are made by a cool static analyzer, aren't they?

Yes, cppcheck should have the credit for these findings :)

To reproduce:

$ CPPCHECK_VERSION=2.3
$ curl -s https://codeload.github.com/danmar/cppcheck/tar.gz/${CPPCHECK_VERSION} | tar -zxf - --directory /tmp/
$ (cd /tmp/cppcheck-${CPPCHECK_VERSION}/ && make CFGDIR=/tmp/cppcheck-${CPPCHECK_VERSION}/cfg/ > /dev/null)
$ /tmp/cppcheck-${CPPCHECK_VERSION}/cppcheck \
    --enable=all \
    --language=c++ \
    --std=c++17 \
    -D__cplusplus \
    -DCLIENT_VERSION_BUILD \
    -DCLIENT_VERSION_IS_RELEASE \
    -DCLIENT_VERSION_MAJOR \
    -DCLIENT_VERSION_MINOR \
    -DCLIENT_VERSION_REVISION \
    -DCOPYRIGHT_YEAR \
    -DDEBUG \
    -DHAVE_WORKING_BOOST_SLEEP_FOR \
    -I src/ \
    -q \
    $(git ls-files -- "*.cpp" "*.h" ":(exclude)src/leveldb/" ":(exclude)src/secp256k1/" ":(exclude)src/univalue/") 2>&1 | \
    grep constParameter
src/init.cpp:917:37: style: Parameter 'args' can be declared with const [constParameter]
src/node/coinstats.cpp:115:55: style: Parameter 'stats' can be declared with const [constParameter]
src/pubkey.cpp:253:55: style: Parameter 'ccChild' can be declared with const [constParameter]
src/rpc/rawtransaction_util.cpp:289:143: style: Parameter 'input_errors' can be declared with const [constParameter]
src/script/sigcache.cpp:49:32: style: Parameter 'entry' can be declared with const [constParameter]
src/script/sigcache.cpp:56:34: style: Parameter 'entry' can be declared with const [constParameter]
src/script/sigcache.cpp:69:23: style: Parameter 'entry' can be declared with const [constParameter]
src/test/addrman_tests.cpp:74:32: style: Parameter 'addr' can be declared with const [constParameter]
src/test/net_tests.cpp:78:63: style: Parameter '_addrman' can be declared with const [constParameter]
src/test/util_tests.cpp:1863:48: style: Parameter 'span' can be declared with const [constParameter]
src/validation.cpp:924:67: style: Parameter 'ws' can be declared with const [constParameter]
src/validation.cpp:951:70: style: Parameter 'ws' can be declared with const [constParameter]
src/wallet/feebumper.cpp:114:115: style: Parameter 'coin_control' can be declared with const [constParameter]
src/wallet/interfaces.cpp:80:44: style: Parameter 'wallet' can be declared with const [constParameter]
src/wallet/interfaces.cpp:97:38: style: Parameter 'wallet' can be declared with const [constParameter]

fjahr · 2020-12-06T13:03:47Z

Code review ACK 12dcdaa

luke-jr

utACK

…ut" par…

…ions as const 31b136e Don't declare de facto const reference variables as non-const (practicalswift) 1c65c07 Don't declare de facto const member functions as non-const (practicalswift) Pull request description: _Meta: This is the second and final part of the `const` refactoring series (part one: #20581). **I promise: no more refactoring PRs from me in a while! :)** I'll now go back to focusing on fuzzing/hardening!_ Changes in this PR: * Don't declare de facto const member functions as non-const * Don't declare de facto const reference variables as non-const Awards for finding candidates for the above changes go to: * `clang-tidy`'s [`readability-make-member-function-const`](https://clang.llvm.org/extra/clang-tidy/checks/readability-make-member-function-const.html) check ([list of `clang-tidy` checks](https://clang.llvm.org/extra/clang-tidy/checks/list.html)) * `cppcheck`'s `constVariable` check ([list of `cppcheck` checks](https://sourceforge.net/p/cppcheck/wiki/ListOfChecks/)) See #18920 for instructions on how to analyse Bitcoin Core using Clang Static Analysis, `clang-tidy` and `cppcheck`. ACKs for top commit: ajtowns: ACK 31b136e jonatack: ACK 31b136e theStack: ACK 31b136e ❄️ Tree-SHA512: f58f8f00744219426874379e9f3e9331132b9b48e954d24f3a85cbb858fdcc98009ed42ef7e7b4619ae8af9fc240a6d8bfc1c438db2e97b0ecd722a80dcfeffe

glozow · 2021-01-18T23:22:45Z

src/validation.cpp

@@ -505,13 +505,13 @@ class MemPoolAccept

    // Run the script checks using our policy flags. As this can be slow, we should
    // only invoke this on transactions that have otherwise passed policy checks.
-    bool PolicyScriptChecks(ATMPArgs& args, Workspace& ws, PrecomputedTransactionData& txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
+    bool PolicyScriptChecks(ATMPArgs& args, const Workspace& ws, PrecomputedTransactionData& txdata) EXCLUSIVE_LOCKS_REQUIRED(cs_main);


Er, would it be alright if I changed the Workspace here back to non-const? I'd interpret Workspace as an "in-out" parameter used throughout MemPoolAccept::AcceptSingleTransaction. As I understand it, this PR makes it const for 2 of the intermediate steps based on some code analysis, but I think it might just be coincidentally unmodified inside those functions 😅 I'd like to be able to update the workspace inside PolicyScriptChecks/ConsensusScriptChecks.

Sure, just remove the const again. While the changes here are correct (as in adding a const will still compile), they probably don't make sense conceptually.

@glozow Absolutely! What is const is not necessarily const over time :)

The C++ const correctness FAQ (isocpp.org) is great reading on the topic!

Coolio, thanks 🤗

…by ref to const instead of ref to non-const Summary: This is a backport of [[bitcoin/bitcoin#20581 | core#20581]] Test Plan: `ninja all check-all` Reviewers: #bitcoin_abc, Fabien Reviewed By: #bitcoin_abc, Fabien Differential Revision: https://reviews.bitcoinabc.org/D11094

…ut" parameters: pass by ref to const instead of ref to non-const

Don't make "in" parameters look like "out"/"in-out" parameters: pass …

12dcdaa

…by ref to const instead of ref to non-const

fanquake added the Refactoring label Dec 6, 2020

DrahtBot mentioned this pull request Dec 6, 2020

RPC: Show fee in results for signrawtransaction* for segwit inputs #18479

Closed

hebasto approved these changes Dec 6, 2020

View reviewed changes

luke-jr approved these changes Dec 6, 2020

View reviewed changes

maflcko merged commit 9385549 into bitcoin:master Dec 6, 2020

practicalswift mentioned this pull request Dec 6, 2020

Declare de facto const reference variables/member functions as const #20584

Merged

sidhujag pushed a commit to syscoin/syscoin that referenced this pull request Dec 6, 2020

Merge bitcoin#20581: Don't make "in" parameters look like "out"/"in-o…

7aaed70

…ut" par…

glozow reviewed Jan 18, 2021

View reviewed changes

practicalswift deleted the const-ref-parameters branch April 10, 2021 19:43

kwvg added a commit to kwvg/dash that referenced this pull request Jul 18, 2022

merge bitcoin#20581: Don't make "in" parameters look like "out"/"in-o…

7daf402

…ut" parameters: pass by ref to const instead of ref to non-const

kwvg added a commit to kwvg/dash that referenced this pull request Aug 9, 2022

merge bitcoin#20581: Don't make "in" parameters look like "out"/"in-o…

979a7ec

…ut" parameters: pass by ref to const instead of ref to non-const

bitcoin locked as resolved and limited conversation to collaborators Aug 16, 2022

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Don't make "in" parameters look like "out"/"in-out" parameters: pass by ref to const instead of ref to non-const #20581

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Don't make "in" parameters look like "out"/"in-out" parameters: pass by ref to const instead of ref to non-const #20581

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