fix: Improve Error Casting

[metal-messiah]

Improve detection of line and column to allow errors that throw without a stack -- such as some chrome errors -- to still get basic error location information

Overview

The primary goal of this PR was to address an issue where certain browsers (Chrome) can emit errors without a stack property under certain circumstances. These errors are emitted with a line and column, but the previous implementation of the agent blindly ignored that data if the error was an instance of the Error class. This PR:

• Checks if the error has a stack before accepting it blindly
• Centralizes the error casting behavior
• Removes the need for intercepting fn-err messages for SPA decoration by diverting that behavior to the SPA instrument class
  • This was necessary to keep in the agent because function errors can propagate through the agent faster than the event handler can, including errors thrown in the createTracer API, and if we rely solely on the errorEvent, these errors can actually throw after the SPA interaction has already closed. The agent will decorate the errors directly in the SPA feature now, so that by the time they are seen in the error feature, they already have interaction information tied to them.
• Removes the need to de-dupe in the error instrument class since fn-err and errorEvent no longer clash.

Related Issue(s)

NR-262956

Testing

New unit & wdio tests have been added

[github-actions]

Asset Size Report

Merging this pull request will result in the following asset size changes:

Agent	Asset	Previous Size	New Size	Diff
lite	loader	31.38 kB / 10.99 kB (gzip)	31.42 kB / 11 kB (gzip)	0.13% / 0.1% (gzip)
lite	async-chunk	50.99 kB / 16.59 kB (gzip)	50.99 kB / 16.59 kB (gzip)	0% / 0% (gzip)
pro	loader	52.11 kB / 17.68 kB (gzip)	51.97 kB / 17.67 kB (gzip)	-0.27% / -0.08% (gzip)
pro	async-chunk	93.54 kB / 28.48 kB (gzip)	93.72 kB / 28.52 kB (gzip)	0.19% / 0.13% (gzip)
spa	loader	60.02 kB / 20.1 kB (gzip)	60.08 kB / 20.15 kB (gzip)	0.1% / 0.26% (gzip)
spa	async-chunk	108.54 kB / 32.87 kB (gzip)	108.99 kB / 32.95 kB (gzip)	0.41% / 0.24% (gzip)
lite-polyfills	loader	125.19 kB / 40.25 kB (gzip)	125.23 kB / 40.26 kB (gzip)	0.03% / 0.02% (gzip)
lite-polyfills	async-chunk	65.79 kB / 18.97 kB (gzip)	65.79 kB / 18.97 kB (gzip)	0% / 0% (gzip)
pro-polyfills	loader	147.25 kB / 46.57 kB (gzip)	146.85 kB / 46.48 kB (gzip)	-0.28% / -0.21% (gzip)
pro-polyfills	async-chunk	127.92 kB / 33.39 kB (gzip)	128.12 kB / 33.43 kB (gzip)	0.15% / 0.11% (gzip)
spa-polyfills	loader	155.24 kB / 48.68 kB (gzip)	155.04 kB / 48.66 kB (gzip)	-0.12% / -0.04% (gzip)
spa-polyfills	async-chunk	144.64 kB / 37.99 kB (gzip)	145.12 kB / 38.08 kB (gzip)	0.33% / 0.24% (gzip)

[codecov]

Codecov Report

Attention: Patch coverage is 91.66667% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 87.06%. Comparing base (44f229e) to head (def5525).
Report is 3 commits behind head on main.

Files	Patch %	Lines
src/features/jserrors/instrument/index.js	33.33%	2 Missing ⚠️
src/features/jserrors/shared/cast-error.js	94.87%	2 Missing ⚠️
src/features/jserrors/aggregate/index.js	75.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1014      +/-   ##
==========================================
+ Coverage   86.64%   87.06%   +0.42%     
==========================================
  Files         154      155       +1     
  Lines        7126     7122       -4     
  Branches     1414     1434      +20     
==========================================
+ Hits         6174     6201      +27     
+ Misses        829      806      -23     
+ Partials      123      115       -8     

Flag	Coverage Δ
integration-tests	90.82% <80.64%> (+0.09%)	⬆️
unit-tests	74.80% <85.10%> (+0.60%)	⬆️

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[github-actions]

Last ran on May 07, 2024 11:46:07 CDT
Checking merge of (def5525) into main (44f229e)

[patrickhousley]

Looks good. I just have the one question about how our decoration of the error object could clash with multiple agents running on the same page.