Adds a DAP server with support for debugging sway unit tests

[sdankel]

Description

Related FuelLabs/sway-vscode-plugin#166

Adds a DAP server as a new forc plugin, forc-debug. This enables a UI debugging experience in IDEs such as VSCode.

For now, only debugging forc tests is supported. Users can:

• set breakpoints inside of forc tests
• step through the test, one VM instruction at a time, or continue to the next breakpoint
• debug through multiple tests sequentially
• see the VM register values in the IDE while debugging
• see the current VM opcode, its inputs, and/or immediate value when when the VM is stopped

Screenshots

Feb-01-2024.21-37-48.mp4

Feb-01-2024.21-44-37.mp4

Local testing

1. Install forc-debug
2. Copy this sample launch.json in the VSCode workspace with sway code to debug:

{
    "version": "0.2.0",
    "configurations": [
        {
        "type": "sway",
        "request": "launch",
        "name": "Debug Sway",
        "program": "${file}"
    }]
}

3. Follow the steps for testing the VSCode extension

Limitations

• Breakpoints only work inside of the project/workspace being debugged
• Stack trace support is limited
• Not every line has source maps. Once debugging, "verified" breakpoints will show red and "unverified" (no source maps) will be greyed out.
• Watch/repl expressions are not yet supported
• Step into/out of is not supported
• If you click "step over" many times in rapid succession, the server takes a while to catch up.

Closes #5394

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[github-actions]

Benchmark for 89b3e02

Click to view benchmark

Test	Base	PR	%
code_action	5.2±0.11ms	5.2±0.19ms	0.00%
code_lens	295.3±7.85ns	306.8±9.43ns	+3.89%
compile	3.1±0.04s	3.1±0.03s	0.00%
completion	4.8±0.05ms	4.9±0.27ms	+2.08%
did_change_with_caching	3.0±0.03s	3.0±0.05s	0.00%
document_symbol	1003.9±39.44µs	956.7±19.92µs	-4.70%
format	89.7±1.04ms	90.0±0.74ms	+0.33%
goto_definition	364.1±9.39µs	360.8±7.27µs	-0.91%
highlight	9.0±0.14ms	8.9±0.20ms	-1.11%
hover	544.3±5.81µs	537.7±7.16µs	-1.21%
idents_at_position	122.3±0.66µs	122.2±1.67µs	-0.08%
inlay_hints	659.9±22.44µs	650.6±19.39µs	-1.41%
on_enter	482.1±18.08ns	498.6±18.23ns	+3.42%
parent_decl_at_position	3.6±0.09ms	3.6±0.04ms	0.00%
prepare_rename	358.1±10.54µs	361.0±5.61µs	+0.81%
rename	9.6±0.17ms	9.4±0.28ms	-2.08%
semantic_tokens	1062.1±24.90µs	1031.2±20.57µs	-2.91%
token_at_position	358.3±4.78µs	354.5±4.37µs	-1.06%
tokens_at_position	3.6±0.04ms	3.6±0.06ms	0.00%
tokens_for_file	417.4±2.53µs	418.3±4.35µs	+0.22%
traverse	39.3±0.88ms	38.7±0.84ms	-1.53%

[kayagokalp]

Huge work! Very excited for this 🚀 I left some nits and comments here and there but we can merge it as it is and discuss next steps in separate issues/PRs :)

[github-actions]

Benchmark for 15ffa7f

Click to view benchmark

Test	Base	PR	%
code_action	5.1±0.14ms	5.1±0.09ms	0.00%
code_lens	286.7±7.31ns	293.4±8.73ns	+2.34%
compile	2.9±0.03s	3.1±0.13s	+6.90%
completion	4.7±0.04ms	4.8±0.01ms	+2.13%
did_change_with_caching	2.8±0.02s	2.8±0.02s	0.00%
document_symbol	1030.8±47.76µs	981.1±30.83µs	-4.82%
format	71.4±0.81ms	72.2±1.00ms	+1.12%
goto_definition	353.7±5.95µs	361.6±7.92µs	+2.23%
highlight	8.8±0.20ms	8.7±0.02ms	-1.14%
hover	524.0±9.16µs	535.8±6.76µs	+2.25%
idents_at_position	122.9±0.26µs	121.3±0.71µs	-1.30%
inlay_hints	637.4±8.39µs	658.8±21.46µs	+3.36%
on_enter	491.1±11.14ns	478.1±9.51ns	-2.65%
parent_decl_at_position	3.6±0.04ms	3.6±0.04ms	0.00%
prepare_rename	348.5±6.25µs	361.9±7.46µs	+3.85%
rename	9.1±0.15ms	9.1±0.13ms	0.00%
semantic_tokens	1020.7±10.38µs	1015.5±15.85µs	-0.51%
token_at_position	350.5±3.57µs	357.9±2.28µs	+2.11%
tokens_at_position	3.6±0.02ms	3.6±0.06ms	0.00%
tokens_for_file	408.4±4.67µs	409.6±2.29µs	+0.29%
traverse	37.5±0.89ms	37.2±0.78ms	-0.80%

[JoshuaBatty]

Great work Sophie :)

[github-actions]

Benchmark for 25eb563

Click to view benchmark

Test	Base	PR	%
code_action	5.2±0.01ms	5.4±0.14ms	+3.85%
code_lens	286.0±4.84ns	286.4±7.47ns	+0.14%
compile	2.9±0.02s	3.0±0.03s	+3.45%
completion	4.7±0.11ms	5.0±0.24ms	+6.38%
did_change_with_caching	2.8±0.02s	2.9±0.03s	+3.57%
document_symbol	1032.5±48.70µs	970.8±8.26µs	-5.98%
format	75.0±1.19ms	75.7±0.57ms	+0.93%
goto_definition	359.7±6.09µs	364.5±5.94µs	+1.33%
highlight	8.8±0.20ms	9.0±0.23ms	+2.27%
hover	532.0±7.17µs	543.7±10.61µs	+2.20%
idents_at_position	121.3±0.41µs	122.4±0.44µs	+0.91%
inlay_hints	645.5±27.78µs	658.3±21.86µs	+1.98%
on_enter	500.3±7.18ns	492.3±8.43ns	-1.60%
parent_decl_at_position	3.7±0.05ms	3.6±0.08ms	-2.70%
prepare_rename	370.0±7.78µs	361.1±7.48µs	-2.41%
rename	9.1±0.02ms	9.4±0.13ms	+3.30%
semantic_tokens	1014.9±10.38µs	1056.2±11.85µs	+4.07%
token_at_position	365.7±2.45µs	355.9±4.61µs	-2.68%
tokens_at_position	3.7±0.03ms	3.6±0.05ms	-2.70%
tokens_for_file	492.3±5.01µs	411.6±3.47µs	-16.39%
traverse	37.3±1.13ms	37.0±0.91ms	-0.80%

[tritao]

Great to see this one merged, awesome work ❤️