fix: compare system packs in pipeline step 5

Step 5 built emulator packs one profile at a time, where two profiles never share a path. It now also builds each system pack that gathers several profiles and compares it with verify. The first run found five standalone MSX and ColecoVision packs where verify skipped the data tree of a profile the system filter left without files, and credited msx-emu's copies the pack never wrote. verify now places those trees too: 541 system packs, all equal.

scripts/pipeline.py

@@ -22,7 +22,7 @@ Steps, numbered as the run prints them:
   4c   --manifest-targets           per-target core lists
   4d   bundled_only.py --strict     copies only an emulator install provides
   4e   generate_games_index.py      install/games/: what the games-on-card mode reads
-  5    consistency check            verify == pack: counts, paths, every emulator pack
+  5    consistency check            verify == pack: counts, paths, emulator and system packs
   6    --verify-packs               pack integrity, extraction and hashes
   7    generate_readme.py           README.md and CONTRIBUTING.md
        generate_installer_doc.py    run samples and tables of wiki/installer.md
@@ -518,7 +518,7 @@ def check_emulator_packs(
     emulators_dir: str = "emulators", platforms_dir: str = "platforms",
     db_path: str = "database.json",
 ) -> bool:
-    """Build every emulator pack in memory and compare it with verify --emulator.
+    """Build every emulator and system pack in memory and compare it with verify.
 
     Each profile in each build it has (libretro, standalone): the paths the
     pack fills with the profile's files against the ones verify credits. No
@@ -528,9 +528,11 @@ def check_emulator_packs(
     import verify  # noqa: PLC0415
     from common import (  # noqa: PLC0415
         ProfileSelectionError,
+        _norm_system_id,
         build_zip_contents_index,
         load_database,
         load_emulator_profiles,
+        profiles_for_systems,
         select_emulator_profiles,
     )
 
@@ -566,7 +568,45 @@ def check_emulator_packs(
                 print("\n".join(lines))
                 all_ok = False
     print(f"  {compared} emulator packs compared, {'all equal' if all_ok else 'differences above'}")
-    return all_ok
+    # A system pack builds every profile of the system together: a placement
+    # rule that only goes wrong when two profiles share a path (the bluemsx
+    # tree beside msx-emu's files) never meets in a one-profile pack.
+    systems = sorted({
+        _norm_system_id(str(sid))
+        for profile in profiles.values()
+        if profile.get("type") not in ("launcher", "alias", "test")
+        for sid in profile.get("systems") or []
+    })
+    systems_ok = True
+    compared = 0
+    for sid in systems:
+        for standalone in (False, True):
+            matching = profiles_for_systems(profiles, [sid], standalone)
+            if len(matching) < 2:
+                continue
+            record = generate_pack.PackRecord()
+            with contextlib.redirect_stdout(io.StringIO()), \
+                    contextlib.redirect_stderr(io.StringIO()):
+                generate_pack.generate_emulator_pack(
+                    matching, emulators_dir, db, "bios", "", standalone, zip_contents,
+                    offline=True, platforms_dir=platforms_dir, record=record,
+                    system_ids=[sid],
+                )
+                report = verify.verify_emulator(
+                    matching, emulators_dir, db, standalone, platforms_dir=platforms_dir,
+                    system_ids=[sid],
+                )
+            compared += 1
+            label = f"--system {sid}{' --standalone' if standalone else ''}"
+            lines = _set_difference_lines(
+                label, set(report["pack_destinations"]), set(record.files)
+            )
+            if lines:
+                print("\n".join(lines))
+                systems_ok = False
+    print(f"  {compared} system packs compared, "
+          f"{'all equal' if systems_ok else 'differences above'}")
+    return all_ok and systems_ok
 
 
 class _Skipped:

scripts/verify.py

@@ -2116,6 +2116,30 @@ def verify_emulator(
             return
         placed[dest.lower()] = (path, owner, dest)
         _register_path(dest, placed_files, placed_parents)
+
+    def occupy_trees(emu_name: str, profile: dict) -> None:
+        """The profile's data trees follow its files in the pack, which
+        writes them even when the system filter leaves it no file:
+        bluemsx's Machines/ tree holds msx-emu's coleco.rom path in a
+        --system colecovision pack."""
+        for dd in deliverable(profile.get("data_directories", []), standalone):
+            cache = (data_registry or {}).get(dd.get("ref", ""), {}).get("local_cache", "")
+            if not cache or not os.path.isdir(cache):
+                continue
+            dd_dest = dd.get("destination", "")
+            structure = profile.get("pack_structure")
+            prefix = (
+                structure.get("standalone" if standalone else "libretro", "")
+                if structure else ""
+            )
+            if prefix:
+                dd_dest = f"{prefix}/{dd_dest}" if dd_dest else prefix
+            for root, _dirs, names in os.walk(cache):
+                for fname in names:
+                    src = os.path.join(root, fname)
+                    rel = os.path.relpath(src, cache).replace(os.sep, "/")
+                    occupy(f"{dd_dest}/{rel}" if dd_dest else rel, src, emu_name)
+
     for emu_name, profile in sorted(selected):
         files = expand_agnostic_entries(
             expand_directory_entries(
@@ -2162,6 +2186,7 @@ def verify_emulator(
                     "ground_truth": [],
                 }
             )
+            occupy_trees(emu_name, profile)
             continue
 
         # Verify archives as units (e.g., neogeo.zip, aes.zip)
@@ -2424,24 +2449,7 @@ def verify_emulator(
                 ) > _SEVERITY_ORDER.get(prev_sev, 0):
                     file_severity[dest] = sev
 
-        # The profile's data trees follow its files in the pack.
-        for dd in deliverable(profile.get("data_directories", []), standalone):
-            cache = (data_registry or {}).get(dd.get("ref", ""), {}).get("local_cache", "")
-            if not cache or not os.path.isdir(cache):
-                continue
-            dd_dest = dd.get("destination", "")
-            structure = profile.get("pack_structure")
-            prefix = (
-                structure.get("standalone" if standalone else "libretro", "")
-                if structure else ""
-            )
-            if prefix:
-                dd_dest = f"{prefix}/{dd_dest}" if dd_dest else prefix
-            for root, _dirs, names in os.walk(cache):
-                for fname in names:
-                    src = os.path.join(root, fname)
-                    rel = os.path.relpath(src, cache).replace(os.sep, "/")
-                    occupy(f"{dd_dest}/{rel}" if dd_dest else rel, src, emu_name)
+        occupy_trees(emu_name, profile)
 
     counts = {
         Severity.OK: 0,