91 lines
3.1 KiB
Markdown
91 lines
3.1 KiB
Markdown
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# Bisecting
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NOTE: THIS IS WORK IN PROGRESS
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`bisect.sh` is a script to bisect issues.
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## Command
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```
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./bisect.sh <hash-good> <hash-bad> "<cppcheck-options>"
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```
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`hash-good` - the last known good commit hash - in case of daca it is the last tagged minor release (not patch release - i.e. 2.x)
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`hash-bad` - the known bad commit hash - in case of daca the one from the `head-info:` line
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`cppcheck-options` - the options for the Cppcheck invokation - in case of daca the ones from the `cppcheck-options:` line and the path to the folder/file to scan
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If possible use `main` as the function to test stuff with since it won't emit an `unusedFunction` warning.
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## Bisecting scan time regressions
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We use daca to track differences in scan time. An overview of regressions in scan time can be found at http://cppcheck1.osuosl.org:8000/time_gt.html.
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You need to download the archive as specified by the second line in the output and extract it.
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If the overall scan time regressed you need to specify the whole folder.
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If a timeout (potential hang) was introduced you can simply specify the file from `error: Internal error: Child process crashed with signal 15 [cppcheckError]`.
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## Bisecting result regressions
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Results regressions are being bisected based on the `--error-exitcode=` result.
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If nothing is found the result will be `0` and it is treated as a _good_ commit.
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If a finding occurs the result will be `1` which is treated as a _bad_ commit.
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### False positive
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Provide a code sample which will trigger the false postive.
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```cpp
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// cppcheck-suppress unusedFunction
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static void f()
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{
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<code triggering FP>
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}
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```
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### False negative
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Provide a code sample which will trigger a `unmatchedSuppression`.
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```cpp
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// cppcheck-suppress unusedFunction
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static void f()
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{
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// cppcheck-suppress unreadVariable
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int i;
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}
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```
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## Notes
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### Compilation issues:
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- 2.5 and before can only be built with GCC<=10 because of missing includes caused by cleanups within the standard headers. You need to specify `CXX=g++-10`.
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- 1.88 and 1.89 cannot be compiled:
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```
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make: python: No such file or directory
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```
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- 1.39 to 1.49 (possibly more versions - 1.54 and up work) cannot be compiled:
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```
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lib/mathlib.cpp:70:42: error: invalid conversion from ‘char’ to ‘char**’ [-fpermissive]
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70 | return std::strtoul(str.c_str(), '\0', 16);
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| ^~~~
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| char
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```
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- some commits between 2.0 and 2.2 cannot be compiled:
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```
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cli/cppcheckexecutor.cpp:333:22: error: size of array ‘mytstack’ is not an integral constant-expression
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333 | static char mytstack[MYSTACKSIZE]= {0}; // alternative stack for signal handler
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| ^~~~~~~~~~~
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```
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RESOLVED: a hot-patch is applied before compilation.
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- some commits between 1.54 and 1.55 cannot be compiled:
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```
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lib/preprocessor.cpp:2103:5: error: ‘errorLogger’ was not declared in this scope; did you mean ‘_errorLogger’?
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2103 | errorLogger->reportInfo(errmsg);
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| ^~~~~~~~~~~
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| _errorLogger
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```
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