{"record":{"id":"9da461b939da1817","repo":"Lightning-AI/pytorch-lightning","slug":"f-trainer-barebones-true-log-every-n-steps-log","errorCode":null,"errorMessage":"f\"`Trainer(barebones=True, log_every_n_steps={log_every_n_steps!r})` was passed.\" \" Logging can impact raw speed so it is disabled in barebones mode.\"","messagePattern":"f\"`Trainer\\(barebones=True, log_every_n_steps=(.+?)\\)` was passed\\.\" \" Logging can impact raw speed so it is disabled in barebones mode\\.\"","errorType":"validation","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"src/lightning/pytorch/trainer/trainer.py","lineNumber":356,"sourceCode":"                raise ValueError(\n                    f\"`Trainer(barebones=True, enable_checkpointing={enable_checkpointing!r})` was passed.\"\n                    \" Checkpointing can impact raw speed so it is disabled in barebones mode.\"\n                )\n            enable_checkpointing = False\n            if logger is not None and logger is not False:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, logger={logger!r})` was passed.\"\n                    \" Logging can impact raw speed so it is disabled in barebones mode.\"\n                )\n            logger = False\n            if enable_progress_bar:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, enable_progress_bar={enable_progress_bar!r})` was passed.\"\n                    \" The progress bar can impact raw speed so it is disabled in barebones mode.\"\n                )\n            enable_progress_bar = False\n            if log_every_n_steps is not None and log_every_n_steps != 0:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, log_every_n_steps={log_every_n_steps!r})` was passed.\"\n                    \" Logging can impact raw speed so it is disabled in barebones mode.\"\n                )\n            log_every_n_steps = 0\n            if enable_model_summary:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, enable_model_summary={enable_model_summary!r})` was passed.\"\n                    \" Model summary can impact raw speed so it is disabled in barebones mode.\"\n                )\n            enable_model_summary = False\n            if num_sanity_val_steps is not None and num_sanity_val_steps != 0:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, num_sanity_val_steps={num_sanity_val_steps!r})` was passed.\"\n                    \" Sanity checking can impact raw speed so it is disabled in barebones mode.\"\n                )\n            num_sanity_val_steps = 0\n            # opt-ins\n            if fast_dev_run is not False and fast_dev_run != 0:","sourceCodeStart":338,"sourceCodeEnd":374,"githubUrl":"https://github.com/Lightning-AI/pytorch-lightning/blob/9fed5c27d2a62ff0efd6c3573599921d6ff67c14/src/lightning/pytorch/trainer/trainer.py#L338-L374","documentation":"Trainer was instantiated with barebones=True (speed benchmarking mode) while log_every_n_steps was set to a non-zero value. Barebones mode disables anything that can impact raw speed, including logging, so the constructor rejects incompatible settings immediately instead of silently skewing benchmarks.","triggerScenarios":"Trainer(barebones=True, log_every_n_steps=50) (any value other than None or 0).","commonSituations":"Copying a production Trainer config (which usually sets log_every_n_steps=50) and just adding barebones=True for a speed benchmark run.","solutions":["Remove log_every_n_steps from the Trainer call when using barebones=True","Set log_every_n_steps=0 or None explicitly","Drop barebones=True if you need logging"],"exampleFix":"// before\ntrainer = Trainer(barebones=True, log_every_n_steps=50)\n// after\ntrainer = Trainer(barebones=True)","handlingStrategy":"validation","validationCode":"log_every = cfg.get(\"log_every_n_steps\", 0)\nif cfg.get(\"barebones\") and (log_every is not None and log_every != 0):\n    del cfg[\"log_every_n_steps\"]\ntrainer = Trainer(**cfg)","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Keep a separate minimal benchmark Trainer config instead of toggling barebones on the production one","Remember barebones=True force-disables progress bar, logging, model summary, sanity check and rejects fast_dev_run/detect_anomaly/profiler"],"tags":["trainer","barebones","logging","misconfiguration","pytorch-lightning"],"backgroundTag":"invalid-argument-combination","analyzedSha":"9fed5c27d2a62ff0efd6c3573599921d6ff67c14","analyzedAt":"2026-08-28T11:52:41.083Z","schemaVersion":2},"datasetVersion":"2026-08-28T16:17:29.566Z"}