fix: show the save_to_* deprecation to users, attributed to their code

[davidberenstein1957]

Description

The save_to_* deprecation is now a FutureWarning (shown by default per PEP 565), and its stacklevel is computed by a new _caller_stacklevel() helper, which walks the stack to the first frame outside the codecarbon package (skipping the contextlib frame added by @suppress). The warning now points at the user's EmissionsTracker(...) / OfflineEmissionsTracker(...) line instead of emissions_tracker.py. In codecarbon/cli/main.py, monitor now passes output_methods= built from configuration, with OutputMethod.API added for --api and removed for --no-api, preserving save_to_api=api's add/remove behaviour and making --api work even when output_methods is set in the config; detect passes output_methods=[]. codecarbon/cli/monitor.py drops the save_to_logger=False argument, which was the default anyway.

Related Issue

Fixes #1323

Motivation and Context

The deprecation warning was raised inside _resolve_output_methods, so it was attributed to emissions_tracker.py, and Python's default filter only shows DeprecationWarning from __main__, which dropped the warning for every user. FutureWarning is the correct category for deprecations aimed at end users that must always be shown, and it also makes stacklevel accuracy matter for pointing at the right line.

How Has This Been Tested?

• test_deprecation_warning_survives_the_default_filter now also asserts w.filename == __file__ for both tracker classes.
• CLI tests assert on output_methods instead of save_to_api; a new parametrised test_monitor_api_flag_adds_to_configured_output_methods pins the add/remove behaviour against configured outputs.

Screenshots (if appropriate):

N/A

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

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Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the docs/how-to/contributing.md document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov]

Codecov Report

❌ Patch coverage is 96.42857% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 91.72%. Comparing base (e5e46ab) to head (db90765).

Files with missing lines	Patch %	Lines
codecarbon/emissions_tracker.py	92.85%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1346      +/-   ##
==========================================
+ Coverage   91.70%   91.72%   +0.02%     
==========================================
  Files          49       49              
  Lines        5157     5183      +26     
==========================================
+ Hits         4729     4754      +25     
- Misses        428      429       +1     

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[benoit-cty]

🤖 This review comment was written and posted by Claude Opus 5.5 (AI assistant), at the request of @benoit-cty. Findings were checked by reading the code and running tests locally (merged with current master where relevant), but please double-check before acting on them.

Verdict: 🔧 Request changes

The title and description mention a dynamic stacklevel and moving the CLI to output_methods=. The single commit in this PR only changes DeprecationWarning to FutureWarning and keeps stacklevel=2.

Must fix:

1. The CLI now shows users a warning they can't act on. FutureWarning is shown by default, but the CLI itself still passes the deprecated arguments:

   • codecarbon/cli/main.py:425 passes save_to_api= on every online monitor run
   • codecarbon/cli/main.py:476 (detect) passes save_to_file=False
   • codecarbon/cli/monitor.py:75 passes save_to_logger=False for monitor -- cmd

   I verified that codecarbon detect now prints emissions_tracker.py:572: FutureWarning: The save_to_* parameters are deprecated... on every run. Please migrate these call sites to output_methods= in this same PR.

2. The warning still points at the library, not the caller, so save_to_* DeprecationWarning has the wrong stacklevel and never reaches users #1323 isn't fixed (emissions_tracker.py ~L223-230).

   • Both EmissionsTracker(...) and OfflineEmissionsTracker(...) report emissions_tracker.py:572.
   • Options:
     • compute the stacklevel by walking frames until you leave the codecarbon package
     • on Python 3.12+, use warnings.warn(..., skip_file_prefixes=(os.path.dirname(codecarbon.__file__),)), with the frame-walk as a fallback for older versions
   • The test only checks that a FutureWarning is raised. Please also assert w[0].filename == __file__, so the attribution is locked in.

3. Update the title and description to match what the code does.

Switching to FutureWarning for a user-facing deprecation is reasonable (PEP 565). It just needs points 1 and 2 to go with it.

[davidberenstein1957]

Made the changes in 99b6c55: CLI moved to output_methods=, warning now points at the caller (filename asserted in the test), title and description updated.

[davidberenstein1957]

Merged master to resolve conflicts in db90765.