fix: line end information for CPython < 3.11

[P403n1x87]

Description of the Change

We fix the value of the line end exported in binary MOJO files for samples extracted from CPython < 3.11 and make sure that it is set to 0 to indicate that the information is not available.

Regressions

Because no issues have been reported that relate to this fix, we assume that nobody was relying on the previous behaviour.

Verification Process

Added a test case to validate that no incorrect location information is emitted from CPython versions prior to 3.11.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.87%. Comparing base (ebfd9fd) to head (250d858).

Additional details and impacted files

@@            Coverage Diff             @@
##            devel     #214      +/-   ##
==========================================
+ Coverage   68.67%   68.87%   +0.19%     
==========================================
  Files          27       27              
  Lines        2519     2519              
  Branches      774      774              
==========================================
+ Hits         1730     1735       +5     
+ Misses        457      453       -4     
+ Partials      332      331       -1     

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[github-actions]

Austin Benchmarks

Running Austin benchmarks with Python 3.10.13

Benchmark Summary

Comparison of dev against 3.6.0.

The following scenarios show a statistically significant difference in performance between the two versions.

	Sample Rate	Saturation	Error Rate	Sampling Speed
Wall time [sampling interval: 1]	🟢	🟢	🟡	🟡
RSA keygen [sampling interval: 100]	🔴	🟡	🟡	🟡
Multiprocess wall time [sampling interval: 10]	🟡	🟡	🔴	🟡
Multiprocess wall time [sampling interval: 1000]	🟡	🟡	🟡	🟢

Benchmark Results

Wall time [sampling interval: 1]

Wall time [sampling interval: 1]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	193000 ± 2000	0.99996 ± 2e-05	4e-06 ± 3e-06	7.9 ± 0.3
dev	197000 ± 2000	0.99985 ± 8e-05	4e-06 ± 4e-06	7.7 ± 0.5

Wall time [sampling interval: 10]

Wall time [sampling interval: 10]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	63000 ± 8000	0.36 ± 0.05	1e-05 ± 1e-05	9.6 ± 0.5
dev	63000 ± 8000	0.35 ± 0.06	1.5e-05 ± 1e-05	9.2 ± 0.4

Wall time [sampling interval: 100]

Wall time [sampling interval: 100]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	12400 ± 200	0.0005 ± 0.0001	1e-05 ± 2e-05	9.0 ± 0.5
dev	12300 ± 200	0.0005 ± 0.0002	1e-05 ± 2e-05	8.7 ± 0.5

Wall time [sampling interval: 1000]

Wall time [sampling interval: 1000]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	1850 ± 30	0 ± 0	0 ± 0	10 ± 1
dev	1860 ± 20	0 ± 0	0 ± 0	10.6 ± 1.0

CPU time [sampling interval: 1]

CPU time [sampling interval: 1]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	62000 ± 2000	1 ± 0	9e-06 ± 6e-06	12.8 ± 0.6
dev	62000 ± 3000	1 ± 0	2e-05 ± 1e-05	12.7 ± 0.5

CPU time [sampling interval: 10]

CPU time [sampling interval: 10]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	58000 ± 3000	0.63 ± 0.04	1.8e-05 ± 1e-05	13.1 ± 0.3
dev	60000 ± 3000	0.67 ± 0.06	2e-05 ± 1e-05	13.0 ± 0.5

CPU time [sampling interval: 100]

CPU time [sampling interval: 100]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	6360 ± 10	0.0006 ± 0.0002	2e-05 ± 4e-05	16 ± 1
dev	6360 ± 10	0.0006 ± 0.0002	6e-05 ± 9e-05	17 ± 1

CPU time [sampling interval: 1000]

CPU time [sampling interval: 1000]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	947 ± 1	0 ± 0	0.0001 ± 0.0004	20 ± 2
dev	947 ± 1	0 ± 0	0.0001 ± 0.0002	20 ± 1

RSA keygen [sampling interval: 1]

RSA keygen [sampling interval: 1]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	64000 ± 2000	1 ± 0	0.0001 ± 6e-05	15.1 ± 0.6
dev	60000 ± 7000	1 ± 0	0.00011 ± 0.0001	16 ± 2

RSA keygen [sampling interval: 10]

RSA keygen [sampling interval: 10]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	60000 ± 5000	0.996 ± 0.003	0.0001 ± 0.0001	16 ± 1
dev	61000 ± 6000	0.993 ± 0.007	0.0003 ± 0.0004	16 ± 2

RSA keygen [sampling interval: 100]

RSA keygen [sampling interval: 100]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	6359 ± 6	0.0003 ± 0.0006	0.0001 ± 0.0002	18 ± 2
dev	6340 ± 20	0.002 ± 0.003	0.0005 ± 0.0005	21 ± 3

RSA keygen [sampling interval: 1000]

RSA keygen [sampling interval: 1000]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	944.8 ± 0.7	0 ± 0	0.0002 ± 0.0005	22 ± 2
dev	945 ± 1	0 ± 0	0.001 ± 0.001	23 ± 5

Full metrics [sampling interval: 1]

Full metrics [sampling interval: 1]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	78000 ± 2000	1 ± 0	1.3e-05 ± 9e-06	19.4 ± 0.5
dev	77000 ± 3000	1 ± 0	1.4e-05 ± 1e-05	19.4 ± 0.8

Full metrics [sampling interval: 10]

Full metrics [sampling interval: 10]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	75000 ± 1000	0.89 ± 0.04	1e-05 ± 6e-06	19.8 ± 0.6
dev	77000 ± 2000	0.86 ± 0.03	1.2e-05 ± 7e-06	19.5 ± 0.5

Full metrics [sampling interval: 100]

Full metrics [sampling interval: 100]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	12500 ± 200	0.001 ± 0.0002	2e-05 ± 3e-05	24.3 ± 0.8
dev	12400 ± 200	0.001 ± 0.0002	5e-05 ± 4e-05	24 ± 1

Full metrics [sampling interval: 1000]

Full metrics [sampling interval: 1000]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	1870 ± 20	0 ± 0	0 ± 0	28 ± 1
dev	1850 ± 20	0 ± 0	0 ± 0	27 ± 2

Multiprocess wall time [sampling interval: 1]

Multiprocess wall time [sampling interval: 1]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	7100 ± 800	1 ± 0	8e-05 ± 4e-05	134 ± 5
dev	7300 ± 200	1 ± 0	0.0001 ± 3e-05	132 ± 3

Multiprocess wall time [sampling interval: 10]

Multiprocess wall time [sampling interval: 10]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	6800 ± 1000	0.999 ± 0.001	6e-05 ± 4e-05	135 ± 6
dev	7340 ± 100	0.998 ± 0.002	0.0001 ± 3e-05	132 ± 2

Multiprocess wall time [sampling interval: 100]

Multiprocess wall time [sampling interval: 100]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	6800 ± 600	0.02 ± 0.004	4e-05 ± 2e-05	130 ± 10
dev	7500 ± 800	0.019 ± 0.002	5e-05 ± 1e-05	130 ± 10

Multiprocess wall time [sampling interval: 1000]

Multiprocess wall time [sampling interval: 1000]

	Sample Rate	Saturation	Error Rate	Sampling Speed
3.6.0	6720 ± 90	0.0011 ± 0.0002	6e-06 ± 8e-06	39.2 ± 0.9
dev	6800 ± 100	0.001 ± 0.0002	7e-06 ± 8e-06	38.2 ± 0.8