clang-tidy: Fix modernize-use-nullptr in headers #26708

1. 
   hebasto commented at 9:08 pm on December 15, 2022: member

   Split from bitcoin/bitcoin#26705 as was requested in #26705 (comment).

   To test this PR, consider applying a diff as follows:

    0--- a/src/.clang-tidy
    1+++ b/src/.clang-tidy
    2@@ -12,17 +12,9 @@ readability-redundant-declaration,
    3 readability-redundant-string-init,
    4 '
    5 WarningsAsErrors: '
    6-bugprone-argument-comment,
    7-bugprone-use-after-move,
    8-misc-unused-using-decls,
    9-modernize-use-default-member-init,
   10 modernize-use-nullptr,
   11-performance-for-range-copy,
   12-performance-move-const-arg,
   13-performance-unnecessary-copy-initialization,
   14-readability-redundant-declaration,
   15-readability-redundant-string-init,
   16 '
   17 CheckOptions:
   18  - key: performance-move-const-arg.CheckTriviallyCopyableMove
   19    value: false
   20+HeaderFilterRegex: '.'
   

2. clang-tidy: Fix `modernize-use-nullptr` in headers

   https://clang.llvm.org/extra/clang-tidy/checks/modernize/use-nullptr.html

   adb7dba9de
3. 
   DrahtBot commented at 9:08 pm on December 15, 2022: contributor

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

   Reviews

   See the guideline for information on the review process.

   Type	Reviewers
   ACK	john-moffett
   Concept ACK	kevkevinpal

   If your review is incorrectly listed, please react with 👎 to this comment and the bot will ignore it on the next update.

   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #26705 (clang-tidy: Check headers and fixes them by hebasto)

   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.

4. kevkevinpal approved
5. 
   kevkevinpal commented at 7:16 am on December 16, 2022: contributor

   ACK but I’m going to try and run clang-tidy myself, first time doing so it might take me a bit
6. 
   kevkevinpal commented at 7:33 am on December 16, 2022: contributor

   was able to run clang-tidy but I only saw a message for this part of the code FormatListN() : FormatList(nullptr, 0) {} not sure how to get clang-tidy to complain about the 3 NULL values changed to nullptr
7. 
   hebasto commented at 10:32 am on December 16, 2022: member

   @kevkevinpal

   not sure how to get clang-tidy to complain about the 3 NULL values changed to nullptr

   To observe clang-tidy’s errors, one could apply to the master branch a diff as follows:

    0--- a/src/.clang-tidy
    1+++ b/src/.clang-tidy
    2@@ -12,17 +12,9 @@ readability-redundant-declaration,
    3 readability-redundant-string-init,
    4 '
    5 WarningsAsErrors: '
    6-bugprone-argument-comment,
    7-bugprone-use-after-move,
    8-misc-unused-using-decls,
    9-modernize-use-default-member-init,
   10 modernize-use-nullptr,
   11-performance-for-range-copy,
   12-performance-move-const-arg,
   13-performance-unnecessary-copy-initialization,
   14-readability-redundant-declaration,
   15-readability-redundant-string-init,
   16 '
   17 CheckOptions:
   18  - key: performance-move-const-arg.CheckTriviallyCopyableMove
   19    value: false
   20+HeaderFilterRegex: '.'
   

   and, for example, run a CI task locally:

   0$ MAKEJOBS="-j16" FILE_ENV="./ci/test/00_setup_env_native_tidy.sh" ./ci/test_run_all.sh
   

   or in a personal Cirrus account: https://cirrus-ci.com/task/4659814702252032.

   My local run has in output:

    0/home/hebasto/git/bitcoin/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/./tinyformat.h:511:23: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
    1            : m_value(NULL),
    2                      ^~~~
    3                      nullptr
    4/home/hebasto/git/bitcoin/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/./tinyformat.h:512:26: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
    5            m_formatImpl(NULL),
    6                         ^~~~
    7                         nullptr
    8/home/hebasto/git/bitcoin/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/./tinyformat.h:513:25: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
    9            m_toIntImpl(NULL)
   10                        ^~~~
   11                        nullptr
   12/home/hebasto/git/bitcoin/ci/scratch/build/bitcoin-x86_64-pc-linux-gnu/src/./tinyformat.h:1008:40: error: use nullptr [modernize-use-nullptr,-warnings-as-errors]
   13    public: FormatListN() : FormatList(0, 0) {}
   14                                       ^
   15                                       nullptr
   

8. john-moffett approved
9. 
   john-moffett commented at 6:45 pm on December 16, 2022: contributor

   ACK adb7dba9de95c166103ac7eaf97d5bd83dc19605
10. maflcko merged this on Dec 17, 2022
11. maflcko closed this on Dec 17, 2022

    ---

12. hebasto deleted the branch on Dec 17, 2022
13. sidhujag referenced this in commit fd665e9f18 on Dec 17, 2022
14. 
    kevkevinpal commented at 10:07 pm on December 17, 2022: contributor

    @hebasto thanks I think I was able to figure it out, I ran the CI task locally and then did docker exec -it <containerid> /bin/bash then ran clang-tidy ./src/tinyformat.h and was able to get the correct warning message
15. bitcoin locked this on Dec 17, 2023

Contributors
hebasto DrahtBot kevkevinpal john-moffett