Land the unit-label removal and the Drive fallback on main

src/ml4t_coursework/checks.py

@@ -57,7 +57,6 @@ class Conformance:
     delta: str = ""
     stamped_at: str = ""
     helper_version: str = ""
-    unit: str = ""
 
     def __str__(self) -> str:
         head = f"{self.component}: {'conformant' if self.conformant else 'NOT conformant'}"
@@ -68,7 +67,6 @@ def __str__(self) -> str:
     def to_dict(self) -> dict:
         return {
             "component": self.component,
-            "unit": self.unit,
             "conformant": self.conformant,
             "checks": [{"name": c.name, "passed": c.passed, "detail": c.detail} for c in self.checks],
             "reference_delta": self.delta,
@@ -181,7 +179,7 @@ def run_invariants(contract, obj) -> list[CheckResult]:
 
 def evaluate(contract, obj) -> Conformance:
     """Run all five checks, stopping the gating ones at the first failure."""
-    result = Conformance(component=contract.name, unit=contract.units[0], conformant=True)
+    result = Conformance(component=contract.name, conformant=True)
     stages: list[Callable[[], Any]] = [
         lambda: [run_interface(contract, obj)],
         lambda: [run_leakage(contract, obj)],

src/ml4t_coursework/components.py

@@ -196,7 +196,7 @@ def status() -> str:
         else:
             failed = [c["name"] for c in meta.get("checks", []) if not c["passed"]]
             state = f"NOT conformant ({', '.join(failed) or 'unknown'})"
-        lines.append(f"  {name:<20} unit {contract.units[0]:<5} {state}")
+        lines.append(f"  {name:<20} {state}")
     return "components in your project folder:\n" + "\n".join(lines)
 
 

src/ml4t_coursework/contracts.py

@@ -1,4 +1,11 @@
-"""What a component is, and the registry of the twenty the course asks for.
+"""What a component is, and the registry of the twenty the courses ask for.
+
+A contract says what a component must do. It deliberately does not say which unit writes it: a
+unit number belongs to one course's outline, and more than one course installs this package. A
+Research to Production student is handed all twenty and never sat the Foundations unit that
+writes the baseline, so a number here would appear in their own submission report naming a
+lesson they never took. Each course keeps that mapping beside its own units, where it cannot
+drift out of step with them - and it did drift, in both directions, while it lived here.
 
 One `Contract` per component, declared beside its reference implementation in `reference/`. The
 contract is authored *from* the reference, which is what guarantees it is passable, and every
@@ -23,7 +30,6 @@
 class Contract:
     name: str
     kind: str
-    units: tuple[str, ...]
     summary: str
     probe: Callable[[Any], Any]
     interface: Callable[[Any], None]
@@ -39,7 +45,7 @@ def __post_init__(self) -> None:
             raise ValueError(f"{self.name}: kind must be 'callable' or 'config', got {self.kind!r}")
 
     def describe(self) -> str:
-        lines = [f"{self.name} ({self.kind}, written in unit {' and '.join(self.units)})",
+        lines = [f"{self.name} ({self.kind})",
                  f"  {self.summary}",
                  f"  interface: {self.interface_detail}",
                  f"  leakage probe: {self.leakage_note}"]

src/ml4t_coursework/project.py

@@ -24,14 +24,26 @@ def on_colab() -> bool:
 
 
 def mount_drive(quiet: bool = True) -> bool:
-    """Mount Google Drive when running on Colab. A no-op anywhere else."""
+    """Mount Google Drive when running on Colab. A no-op anywhere else.
+
+    `google.colab` being importable does not mean a Drive can be mounted. The
+    published Colab runtime image has the package but no backend to mount
+    through, so `drive.mount` raises there; a headless or automated session can
+    also reach a mount it cannot complete. Returning False sends `home` to the
+    environment override or the home directory, which is the fallback it already
+    implements. Raising instead would fail before that fallback is ever consulted.
+    """
     try:
         from google.colab import drive  # type: ignore
     except ImportError:
         return False
-    if not (DRIVE_MOUNT / "MyDrive").is_dir():
+    if (DRIVE_MOUNT / "MyDrive").is_dir():
+        return True
+    try:
         drive.mount(str(DRIVE_MOUNT))
-    return True
+    except Exception:
+        return False
+    return (DRIVE_MOUNT / "MyDrive").is_dir()
 
 
 def home(create: bool = True) -> Path:

src/ml4t_coursework/reference/allocator.py

@@ -1,6 +1,7 @@
-"""`allocator` - units 8.1 and 8.2. From a position to a weight.
+"""`allocator`. From a position to a weight.
 
-8.1 maps the signal to weights. 8.2 tightens the same component with the constraint set, which is
+The first unit maps the signal to weights. The second tightens the same component with the
+constraint set, which is
 where the cap and the gross budget stop being implicit.
 """
 
@@ -129,7 +130,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="allocator",
     kind="callable",
-    units=("7.1", "7.2"),
     summary="Turns positions into weights inside a stated gross budget and per-name cap.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/availability_lag.py

@@ -1,4 +1,4 @@
-"""`availability_lag` - unit 2.2. The lag before a datum may be used.
+"""`availability_lag`. The lag before a datum may be used.
 
 This is the decision the rest of the pipeline silently depends on, and its leakage probe is the
 one check `certification.md` calls the most valuable in the course.
@@ -87,7 +87,6 @@ def _leading_gap(obj) -> str:
 register(Contract(
     name="availability_lag",
     kind="callable",
-    units=("2.2",),
     summary="Delays every observation by the time it takes to become usable.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/backtest_config.py

@@ -1,4 +1,4 @@
-"""`backtest_config` - unit 7.2. The assumptions the engine makes, said out loud."""
+"""`backtest_config`. The assumptions the engine makes, said out loud."""
 
 from __future__ import annotations
 
@@ -40,7 +40,6 @@ def _rebalance_is_a_period(obj) -> str:
 register(Contract(
     name="backtest_config",
     kind="config",
-    units=("6.2",),
     summary="Engine, fill assumption and rebalance frequency, with what the engine cannot answer.",
     probe=probe,
     interface=interface_for(FIELDS),

src/ml4t_coursework/reference/baseline_strategy.py

@@ -1,4 +1,4 @@
-"""`baseline_strategy` - unit 2.5. The auditable non-ML rule everything else must beat."""
+"""`baseline_strategy`. The auditable non-ML rule everything else must beat."""
 
 from __future__ import annotations
 
@@ -81,8 +81,8 @@ def _invested(obj) -> str:
     require(len(active) > 100, "the baseline is invested",
             "a rule that holds something over most of the sample",
             f"positions on only {len(active)} of {len(out)} sessions",
-            "A baseline that is mostly in cash is a comparison against cash, which 7.3 already "
-            "makes separately.")
+            "A baseline that is mostly in cash is a comparison against cash, which the cost "
+            "model already prices separately.")
     worst = float((active - 1.0).abs().max())
     require(worst < 1e-6, "the baseline is invested",
             "a fully invested book on every active session",
@@ -114,7 +114,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="baseline_strategy",
     kind="callable",
-    units=("2.5",),
     summary="An auditable non-ML rule, fixed before any result is seen.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/cost_model.py

@@ -1,6 +1,6 @@
-"""`cost_model` - unit 8.3. What trading takes out, before you decide anything survived.
+"""`cost_model`. What trading takes out, before you decide anything survived.
 
-The two decisions in 8.3 - the form, and where its parameters come from - are taught rather than
+The two decisions here - the form, and where its parameters come from - are taught rather than
 built, so the shipped form is the one every student uses and what they choose is its parameters.
 The contract is on the shape any cost model must have, so a student who changes the form still
 gets checked.
@@ -103,7 +103,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="cost_model",
     kind="callable",
-    units=("7.3",),
     summary="Charges the strategy for what it traded, in the units the return is measured in.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/data_panel.py

@@ -1,4 +1,4 @@
-"""`data_panel` - unit 2.1. The stored price panel, loaded with its close convention stated.
+"""`data_panel`. The stored price panel, loaded with its close convention stated.
 
 The file on disk is wide, one column per asset, because that is how a price download arrives and
 how it stores compactly. What the rest of the pipeline works in is long: one row per (date,
@@ -129,7 +129,6 @@ def _unbalanced(obj) -> str:
 register(Contract(
     name="data_panel",
     kind="callable",
-    units=("2.1",),
     summary="Loads the stored price file and returns it long, one row per (date, asset).",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/exit_rule.py

@@ -1,4 +1,4 @@
-"""`exit_rule` - unit 8.4. Position controls, and the one threshold worth calibrating."""
+"""`exit_rule`. Position controls, and the one threshold worth calibrating."""
 
 from __future__ import annotations
 
@@ -135,7 +135,7 @@ def _fires(obj) -> str:
     require(closed > 0, "the rule does something",
             "a position closed somewhere in a 35% fall held throughout",
             "a rule that never fires even then",
-            "A threshold so wide it never triggers is not a control; 8.4's own result is that a "
+            "A threshold so wide it never triggers is not a control; this unit's own result is that a "
             "stop grid need not identify a stable threshold, which is a different finding from "
             "never testing one.")
     return f"{closed} position-days closed by the rule"
@@ -144,7 +144,6 @@ def _fires(obj) -> str:
 register(Contract(
     name="exit_rule",
     kind="callable",
-    units=("7.4",),
     summary="Closes a position that has breached its control, and leaves it closed.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/features.py

@@ -1,6 +1,6 @@
-"""`features` - units 5.1 and 5.2. A feature is a hypothesis about a driver.
+"""`features`. A feature is a hypothesis about a driver.
 
-5.1 builds one feature that encodes a named driver. 5.2 tightens the same component so the
+The first unit builds one feature that encodes a named driver. The second tightens it so the
 lookback is read against the label horizon and the values are normalized inside each date's
 cross-section rather than against pooled history.
 """
@@ -104,7 +104,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="features",
     kind="callable",
-    units=("4.1", "4.2"),
     summary="Turns prices into the predictors the model sees, normalized within each date.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/fold_splitter.py

@@ -1,4 +1,4 @@
-"""`fold_splitter` - unit 3.1. Walk-forward folds with a label buffer."""
+"""`fold_splitter`. Walk-forward folds with a label buffer."""
 
 from __future__ import annotations
 
@@ -102,7 +102,6 @@ def _buffered(obj) -> str:
 register(Contract(
     name="fold_splitter",
     kind="callable",
-    units=("3.1",),
     summary="Splits a date index into walk-forward train/validation folds with a label buffer.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/holdout_split.py

@@ -1,4 +1,4 @@
-"""`holdout_split` - unit 3.2. A dated cutoff, written down and not opened."""
+"""`holdout_split`. A dated cutoff, written down and not opened."""
 
 from __future__ import annotations
 
@@ -72,7 +72,6 @@ def _covers(obj) -> str:
 register(Contract(
     name="holdout_split",
     kind="callable",
-    units=("3.2",),
     summary="Seals the last stretch of the sample behind a dated cutoff.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/labeler.py

@@ -1,6 +1,7 @@
-"""`labeler` - units 3.3 and 3.4. The outcome the model is asked to predict.
+"""`labeler`. The outcome the model is asked to predict.
 
-3.3 fixes the horizon and what overlap costs. 3.4 tightens the same component so entry and exit
+The first unit fixes the horizon and what overlap costs. The second tightens the same component
+so entry and exit
 are prices actually reachable after the decision, rather than the close of the bar the decision
 was made on.
 """
@@ -93,7 +94,7 @@ def _stamped_on_the_decision(obj) -> str:
 
 
 def _executable(obj) -> str:
-    """3.4's tightening: the entry price is one a decision at t could actually have transacted."""
+    """The executable-price tightening: the entry is a price a decision at t could have transacted."""
     panel = fixtures.panel()
     out = obj(panel)
     close = panel["close"].unstack("asset")
@@ -122,7 +123,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="labeler",
     kind="callable",
-    units=("3.3", "3.4"),
     summary="Turns prices into the outcome a decision at t is judged on, stamped at t.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/model_gbm.py

@@ -1,4 +1,4 @@
-"""`model_gbm` - unit 6.3. Gradient boosting, on the same features and the same split as 6.1."""
+"""`model_gbm`. Gradient boosting, on the same features and the same split as the linear model."""
 
 from __future__ import annotations
 
@@ -65,7 +65,7 @@ def _interface(obj) -> None:
     require(isinstance(out, pd.Series), "interface", "predict to return a Series",
             f"a {type(out).__name__}")
     require(out.index.equals(X_va.index), "interface",
-            "one prediction per row it was asked about, on the same index as 6.1's model, because "
+            "one prediction per row it was asked about, on the same index as the linear model, because "
             "the two are compared",
             f"{len(out)} predictions against {len(X_va)} rows")
 
@@ -103,7 +103,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="model_gbm",
     kind="callable",
-    units=("5.3",),
     summary="A gradient-boosted model with capacity chosen rather than defaulted.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/model_linear.py

@@ -1,4 +1,4 @@
-"""`model_linear` - unit 6.1. The baseline every later result is read against."""
+"""`model_linear`. The baseline every later result is read against."""
 
 from __future__ import annotations
 
@@ -114,7 +114,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="model_linear",
     kind="callable",
-    units=("5.1",),
     summary="A regularized linear model: the baseline every later result is read against.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/objective.py

@@ -1,4 +1,4 @@
-"""`objective` - unit 1.2. What the strategy is judged on, fixed before any result exists."""
+"""`objective`. What the strategy is judged on, fixed before any result exists."""
 
 from __future__ import annotations
 
@@ -26,7 +26,6 @@ def reference():
 register(Contract(
     name="objective",
     kind="config",
-    units=("1.4",),
     summary="The metric the strategy is judged on and the cost tier it is judged under.",
     probe=probe,
     interface=interface_for(FIELDS),

src/ml4t_coursework/reference/preprocessor.py

@@ -1,4 +1,4 @@
-"""`preprocessor` - unit 4.4. Winsorize, scale, impute, all fitted on training rows only."""
+"""`preprocessor`. Winsorize, scale, impute, all fitted on training rows only."""
 
 from __future__ import annotations
 
@@ -136,7 +136,6 @@ def _finite(obj) -> str:
 register(Contract(
     name="preprocessor",
     kind="callable",
-    units=("3.6",),
     summary="Winsorizes, scales and imputes, with every parameter learned on training rows.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/quality_gates.py

@@ -1,4 +1,4 @@
-"""`quality_gates` - unit 2.3. What a breach does, and to which bar."""
+"""`quality_gates`. What a breach does, and to which bar."""
 
 from __future__ import annotations
 
@@ -130,7 +130,6 @@ def _keeps_good(obj) -> str:
 register(Contract(
     name="quality_gates",
     kind="callable",
-    units=("2.3",),
     summary="Voids bars that fail a stated quality gate, and reports which gate caught what.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/signal.py

@@ -1,4 +1,4 @@
-"""`signal` - unit 7.1. From a score to a position: which names, and which way."""
+"""`signal`. From a score to a position: which names, and which way."""
 
 from __future__ import annotations
 
@@ -91,7 +91,6 @@ def _two_sided(obj) -> str:
 register(Contract(
     name="signal",
     kind="callable",
-    units=("6.1",),
     summary="Turns model scores into which names to hold and which way.",
     probe=_probe,
     interface=_interface,

src/ml4t_coursework/reference/strategy_spec.py

@@ -1,4 +1,4 @@
-"""`strategy_spec` - unit 1.1. The family you are in, and the mechanism you are claiming."""
+"""`strategy_spec`. The family you are in, and the mechanism you are claiming."""
 
 from __future__ import annotations
 
@@ -26,7 +26,6 @@ def reference():
 register(Contract(
     name="strategy_spec",
     kind="config",
-    units=("1.3",),
     summary="The strategy family and the economic mechanism the return is claimed to come from.",
     probe=probe,
     interface=interface_for(FIELDS),