refactor: simplify pack label, hash merge, diff exit

scripts/diff_truth.py

@@ -207,7 +207,8 @@ def main() -> None:
         json.dump(reports, sys.stdout, indent=2)
         print()
 
-    if compared < len(platforms) and (args.platform or not compared):
+    # A named platform must be compared; --all must compare at least one.
+    if compared < (len(platforms) if args.platform else 1):
         print(f"compared {compared} of {len(platforms)} platform(s)", file=sys.stderr)
         sys.exit(1)
 

scripts/exporter/baseline.py

@@ -90,16 +90,12 @@ class NativeFile:
             return platform_values
         if source == "truth":
             return truth_values
-        if truth_values and platform_values and not set(truth_values) & set(
-            platform_values
-        ):
+        if not truth_values:
+            return platform_values
+        if not set(truth_values) & set(platform_values):
             return truth_values
-        if truth_values:
-            # Keep the platform's extra accepted revisions alongside ours.
-            merged = list(truth_values)
-            merged.extend(v for v in platform_values if v not in merged)
-            return merged
-        return platform_values
+        # Keep the platform's extra accepted revisions alongside ours.
+        return truth_values + [v for v in platform_values if v not in truth_values]
 
     def hash(self, field_name: str) -> str:
         values = self.hashes(field_name)

scripts/pipeline.py

@@ -71,6 +71,14 @@ def parse_verify_counts(output: str) -> dict[str, tuple[int, int]]:
     return counts
 
 
+def _full_pack_label(label: str) -> str:
+    """The pack name, or "" for a reduced variant such as [source=platform]."""
+    meta = re.search(r"\s+\[([^\]]+)\]$", label)
+    if meta is None:
+        return label
+    return label[: meta.start()] if meta.group(1) == "source=full" else ""
+
+
 def parse_pack_counts(output: str) -> dict[str, tuple[int, int]]:
     """Extract per-pack OK/total from generate_pack output.
 
@@ -85,11 +93,7 @@ def parse_pack_counts(output: str) -> dict[str, tuple[int, int]]:
             # the full, unreduced pack is what verify describes: with
             # --all-variants the six variants shared one label and the last
             # (platform, required) was compared to the full report.
-            label = m.group(1).strip()
-            meta = re.search(r"\s+\[([^\]]+)\]$", label)
-            current_label = label[: meta.start()] if meta else label
-            if meta and meta.group(1) != "source=full":
-                current_label = ""
+            current_label = _full_pack_label(m.group(1).strip())
             continue
         if not current_label:
             continue
@@ -99,7 +103,6 @@ def parse_pack_counts(output: str) -> dict[str, tuple[int, int]]:
         base_m = re.search(r"\((\d+) baseline", line)
         ok_m = re.search(r"(\d+)/(\d+) files OK", line)
         if base_m and ok_m:
-            int(base_m.group(1))
             ok, total = int(ok_m.group(1)), int(ok_m.group(2))
             counts[current_label] = (ok, total)
         elif ok_m:

scripts/slots.py

@@ -350,6 +350,14 @@ def arbitrate(conflict: Conflict, mode: str, addressee: str = "platform") -> Dec
     return Decision(conflict, conflict.platform_claim, FRONTEND_CHECKS_CONTENT)
 
 
+def _pinned_elsewhere(claims: list[Claim], winner: str | None) -> set[str]:
+    """Emulators that pin content the served file does not carry."""
+    return {
+        c.emulator for c in claims
+        if c.emulator and c.local_path != winner and resolution_is_hash_exact(c.status)
+    }
+
+
 def format_decision(decision: Decision) -> str:
     """One line naming the contested slot, the winner and the ground for it."""
     conflict = decision.conflict
@@ -357,11 +365,7 @@ def format_decision(decision: Decision) -> str:
         winner = decision.winner.local_path
         # A claim that only matched a path is answered by whatever file sits
         # there; only one that pins content can be left wanting.
-        pinned_elsewhere = {
-            c.emulator for c in conflict.profile_claims
-            if c.emulator and c.local_path != winner
-            and resolution_is_hash_exact(c.status)
-        }
+        pinned_elsewhere = _pinned_elsewhere(conflict.profile_claims, winner)
         served = sorted({
             c.emulator for c in conflict.profile_claims if c.emulator
         } - pinned_elsewhere)