fix(traces): correct line number in load_traces() error messages (0.3.2)

load_traces() used len(records)+1 as the error line number, which excluded
blank lines and reported a lower-than-actual position. Fixed with
enumerate(f, start=1) so the message always points at the real file line.

Closes #57.

Author: adrida

src/tracer/__init__.py

@@ -78,7 +78,7 @@ def __getattr__(name: str):
     return obj
 
 
-__version__ = "0.3.1"
+__version__ = "0.3.2"
 
 __all__ = [
     # Core API

src/tracer/cloud/client.py

@@ -39,7 +39,7 @@ class CloudError(RuntimeError):
 
 # A real User-Agent: the default "Python-urllib/x" trips Cloudflare's bot
 # protection on app.tracerml.ai (HTTP 403, CF error 1010).
-USER_AGENT = "tracer-cli/0.3.1 (+https://tracerml.ai)"
+USER_AGENT = "tracer-cli/0.3.2 (+https://tracerml.ai)"
 
 
 def _http(

src/tracer/traces/loader.py

@@ -25,15 +25,15 @@ def load_traces(path: Union[str, Path]) -> TraceDataset:
     path = Path(path)
     records = []
     with path.open("r", encoding="utf-8") as f:
-        for line in f:
+        for lineno, line in enumerate(f, start=1):
             line = line.strip()
             if not line:
                 continue
             try:
                 row = json.loads(line)
             except json.JSONDecodeError as exc:
                 raise ValueError(
-                    f"Malformed JSON in {path} at line {len(records) + 1}: {exc}"
+                    f"Malformed JSON in {path} at line {lineno}: {exc}"
                 ) from exc
             # Accept common key aliases so middleware dumps load without
             # reshaping (mirrors the scan loader). Canonical keys are
@@ -42,7 +42,7 @@ def load_traces(path: Union[str, Path]) -> TraceDataset:
             label_key = next((k for k in _LABEL_KEYS if k in row), None)
             if input_key is None or label_key is None:
                 raise ValueError(
-                    f"Trace at line {len(records) + 1} is missing an input and/or "
+                    f"Trace at line {lineno} is missing an input and/or "
                     f"teacher field. Accepted input keys: {_INPUT_KEYS}; "
                     f"teacher keys: {_LABEL_KEYS}. Got keys: {list(row.keys())}"
                 )