doc: reference fuzz coverage steps in quick-start #33536

1. 
   frankomosh commented at 3:57 pm on October 3, 2025: contributor

   Adds a single comment in the libFuzzer quick-start that links to the Developer Notes coverage section. No build flags are changed or shown.
2. frankomosh marked this as ready for review on Oct 3, 2025
3. 
   janb84 commented at 9:47 am on October 6, 2025: contributor

   NACK Developer notes already has an extensive section on generating coverage. Maintaining the same documentation in 2 places is not ideal.
4. in doc/fuzzing.md:27 in 32c0e56c0a

   20@@ -21,6 +21,15 @@ See [further](#run-without-sanitizers-for-increased-throughput) for more informa
   21 There is also a runner script to execute all fuzz targets. Refer to
   22 `./build_fuzz/test/fuzz/test_runner.py --help` for more details.
   23 
   24+If you also want source-based coverage reports, append the instrumentation flags to `cmake --preset=libfuzzer`:
   25+
   26+```sh
   27+$ cmake --preset=libfuzzer \
   

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   maflcko commented at 9:54 am on October 6, 2025:

   not sure about recommending libfuzzer here. It has issues properly counting runs, so coverage will be off. See also https://github.com/bitcoin/bitcoin/blob/a33bd767a37dccf39a094d03c2f62ea81633410f/contrib/devtools/deterministic-fuzz-coverage/src/main.rs#L111-L115

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   frankomosh commented at 10:33 am on October 6, 2025:

   thanks. wasn’t aware of the run counting issues with LibFuzzer.

   So I guess the best approach is to build without the fuzzer sanitizer ?

5. 
   frankomosh commented at 10:34 am on October 6, 2025: contributor

   NACK Developer notes already has an extensive section on generating coverage. Maintaining the same documentation in 2 places is not ideal.

   ok . Would you atleast like to see a reference to the developer notes in this section(assume for someone who lands here first)?

6. 
   janb84 commented at 12:03 pm on October 6, 2025: contributor

   NACK Developer notes already has an extensive section on generating coverage. Maintaining the same documentation in 2 places is not ideal.

   ok . Would you atleast like to see a reference to the developer notes in this section(assume for someone who lands here first)?

   That would be better, imho (although the correct way would be to first read the contributing guide as a developer), but i can understand that one interested in fuzzing would only read the fuzzing readme before the contributing.md.

7. frankomosh force-pushed on Oct 8, 2025
8. frankomosh force-pushed on Oct 8, 2025
9. 
   fanquake commented at 1:48 pm on October 30, 2025: member

   @frankomosh the PR description needs updating to reflect the current change?

   cc @dergoegge @marcofleon

10. frankomosh renamed this:
    doc: add coverage instrumentation hint to libFuzzer quickstart
    doc: reference fuzz coverage steps in quick-start
    on Oct 30, 2025
11. 
    frankomosh commented at 6:11 pm on October 30, 2025: contributor

    @frankomosh the PR description needs updating to reflect the current change?

    cc @dergoegge @marcofleon

    yeah indeed

12. in doc/fuzzing.md:24 in df1815e319

    20@@ -21,6 +21,8 @@ See [further](#run-without-sanitizers-for-increased-throughput) for more informa
    21 There is also a runner script to execute all fuzz targets. Refer to
    22 `./build_fuzz/test/fuzz/test_runner.py --help` for more details.
    23 
    24+For source-based `coverage reports`, see [Developer notes](https://github.com/bitcoin/bitcoin/blob/master/doc/developer-notes.md#compiling-for-fuzz-coverage).
    

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    dergoegge commented at 3:35 pm on November 7, 2025:

    nit:

    0For source-based `coverage reports`, see [developer notes](/doc/developer-notes.md#compiling-for-fuzz-coverage).
    

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    marcofleon commented at 6:21 pm on November 7, 2025:

    nit: Not sure if “coverage reports” needs the backticks here?

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    frankomosh commented at 3:59 am on November 10, 2025:

    done. Thanks

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    frankomosh commented at 4:01 am on November 10, 2025:

    I don’t think they are super helpful. I just removed them in the new commit.
13. 
    dergoegge commented at 3:38 pm on November 7, 2025: member

    Concept ACK - Seems reasonable to mention this in the actual fuzzing docs.
14. 
    marcofleon commented at 6:24 pm on November 7, 2025: contributor

    Concept ACK
15. doc: mention coverage build in quickstart section

    Points a reader to Developer Notes which explains to compile with llvm source based coverage instrumentation

    dee7eec643
16. frankomosh force-pushed on Nov 10, 2025
17. 
    janb84 commented at 9:49 am on November 10, 2025: contributor

    ACK dee7eec64389aa48daff6f7f3ecbd931af72050a

    The author removed the duplicate and redundant code coverage instructions which made me disagree with this PR. The author now only references that there are instructions on generating code coverage for fuzzing elsewhere in the documentation, which seems to me as a reasonable thing and good addition.

    Thank you for changing this.

18. dergoegge approved
19. 
    dergoegge commented at 10:11 am on November 10, 2025: member

    ACK dee7eec64389aa48daff6f7f3ecbd931af72050a
20. fanquake merged this on Nov 10, 2025
21. fanquake closed this on Nov 10, 2025

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22. frankomosh deleted the branch on Nov 10, 2025

Contributors
frankomosh janb84 maflcko fanquake dergoegge marcofleon

Review Requested
marcofleon

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