{"record":{"id":"55ecdf89606ca1c6","repo":"Lightning-AI/pytorch-lightning","slug":"f-trainer-barebones-true-num-sanity-val-steps-n","errorCode":null,"errorMessage":"f\"`Trainer(barebones=True, num_sanity_val_steps={num_sanity_val_steps!r})` was passed.\" \" Sanity checking can impact raw speed so it is disabled in barebones mode.\"","messagePattern":"f\"`Trainer\\(barebones=True, num_sanity_val_steps=(.+?)\\)` was passed\\.\" \" Sanity checking 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":368,"sourceCode":"                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:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, fast_dev_run={fast_dev_run!r})` was passed.\"\n                    \" Development run is not meant for raw speed evaluation so it is disabled in barebones mode.\"\n                )\n            if detect_anomaly:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, detect_anomaly={detect_anomaly!r})` was passed.\"\n                    \" Anomaly detection can impact raw speed so it is disabled in barebones mode.\"\n                )\n            if profiler is not None:\n                raise ValueError(\n                    f\"`Trainer(barebones=True, profiler={profiler!r})` was passed.\"","sourceCodeStart":350,"sourceCodeEnd":386,"githubUrl":"https://github.com/Lightning-AI/pytorch-lightning/blob/9fed5c27d2a62ff0efd6c3573599921d6ff67c14/src/lightning/pytorch/trainer/trainer.py#L350-L386","documentation":"Trainer was created with barebones=True while num_sanity_val_steps was set to a non-zero value. The sanity check runs validation batches before training and can affect raw speed, so barebones mode rejects it.","triggerScenarios":"Trainer(barebones=True, num_sanity_val_steps=2) (anything other than None or 0).","commonSituations":"Standard configs that set num_sanity_val_steps=2 being reused with barebones=True for speed runs.","solutions":["Remove num_sanity_val_steps when using barebones=True","Set num_sanity_val_steps=0 or None","Drop barebones=True if sanity checking is needed"],"exampleFix":"// before\ntrainer = Trainer(barebones=True, num_sanity_val_steps=2)\n// after\ntrainer = Trainer(barebones=True)","handlingStrategy":"validation","validationCode":"if cfg.get(\"barebones\"):\n    cfg[\"num_sanity_val_steps\"] = 0\ntrainer = Trainer(**cfg)","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Treat barebones=True as 'strip everything' — audit every Trainer kwarg against the barebones blocklist"],"tags":["trainer","barebones","sanity-check","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"}