chore(iast): reduce telemetry error messages

[avara1986]

This PR changes how IAST reports errors when an exception occurs, especially in cases where execution happens outside of context. This was originally implemented to analyze which services were triggering this issue, and we used that insight to refactor how IAST creates and destroys context.

However, after that refactor, this information no longer provides value and only adds noise. So now, those telemetry metrics are only emitted if IAST is in debug mode.

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions]

CODEOWNERS have been resolved as:

ddtrace/appsec/_iast/_langchain.py                                      @DataDog/asm-python
ddtrace/appsec/_iast/_logs.py                                           @DataDog/asm-python
ddtrace/appsec/_iast/_metrics.py                                        @DataDog/asm-python
ddtrace/appsec/_iast/_taint_tracking/taint_tracking/taint_range.cpp     @DataDog/asm-python
tests/appsec/iast/aspects/test_fstrings.py                              @DataDog/asm-python
tests/appsec/iast/test_overhead_control_engine.py                       @DataDog/asm-python
tests/appsec/iast/test_telemetry.py                                     @DataDog/asm-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 272 ± 2 ms.

The average import time from base is: 273 ± 2 ms.

The import time difference between this PR and base is: -0.75 ± 0.09 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 1.843 ms (0.68%)

ddtrace.bootstrap.sitecustomize 1.180 ms (0.43%)

ddtrace.bootstrap.preload 1.180 ms (0.43%)

ddtrace.internal.remoteconfig.client 0.629 ms (0.23%)

ddtrace 0.664 ms (0.24%)

ddtrace.internal._unpatched 0.021 ms (0.01%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-06-05 14:17:33

Comparing candidate commit e8ec2d9 in PR branch avara1986/APPSEC-57578-iast_telemetry_logs with baseline commit 0e5abc9 in branch main.

Found 4 performance improvements and 2 performance regressions! Performance is the same for 551 metrics, 7 unstable metrics.

scenario:iastaspects-ljust_aspect

• 🟩 execution_time [-2.716µs; -2.568µs] or [-20.877%; -19.737%]

scenario:iastaspects-lstrip_aspect

• 🟩 execution_time [-2.551µs; -2.408µs] or [-19.685%; -18.579%]

scenario:iastaspects-rstrip_aspect

• 🟩 execution_time [-2.566µs; -2.413µs] or [-19.946%; -18.759%]

scenario:iastaspects-strip_aspect

• 🟩 execution_time [-2.623µs; -2.542µs] or [-20.165%; -19.543%]

scenario:iastaspectsospath-ospathbasename_aspect

• 🟥 execution_time [+653.359ns; +800.890ns] or [+15.446%; +18.934%]

scenario:iastaspectsospath-ospathsplitdrive_aspect

• 🟥 execution_time [+401.969ns; +454.032ns] or [+11.104%; +12.542%]