Add explicit board_level = release (#11305)

Relying on board_level = <empty> was causing some inheritence footguns.
Let's be explicit about what's being released.

bin/generate_ci_matrix.py

@@ -5,8 +5,15 @@
 import argparse
 import json
 import re
+
 from platformio.project.config import ProjectConfig
 
+# Every variant env must declare one of these as its 'board_level':
+#   pr      - smallest subset, built on every PR (and in every larger matrix)
+#   release - the full release matrix, built on push / schedule / workflow_dispatch
+#   extra   - opt-in only, built when explicitly requested via '--level extra'
+BOARD_LEVELS = ("pr", "release", "extra")
+
 parser = argparse.ArgumentParser(description="Generate the CI matrix")
 parser.add_argument("platform", help="Platform to build for")
 parser.add_argument(
@@ -14,7 +21,7 @@ parser.add_argument(
   choices=["extra", "pr"],
   nargs="*",
   default=[],
-  help="Board level to build for (omit for full release boards)",
+  help="Board level to build for (omit for the 'pr' + 'release' matrix)",
 )
 args = parser.parse_args()
 
@@ -39,10 +46,20 @@ for pio_env in pio_envs:
   if not env_platform:
     print(f"Error: Could not determine platform for environment '{pio_env}'")
     exit(1)
+  board_level = cfg.get(f"env:{pio_env}", "board_level", default=None)
+  # Intentionally fail on a missing or unrecognized level: every env must opt in
+  # explicitly, so a new variant can't silently drop out of (or into) the matrix.
+  if board_level not in BOARD_LEVELS:
+    found = f"'{board_level}'" if board_level else "no value"
+    print(
+      f"Error: environment '{pio_env}' has {found} for 'board_level'; "
+      f"expected one of: {', '.join(BOARD_LEVELS)}"
+    )
+    exit(1)
   # Store env details as a dictionary, and add to 'all_envs' list
   env = {
     "ci": {"board": pio_env, "platform": env_platform},
-    "board_level": cfg.get(f"env:{pio_env}", "board_level", default=None),
+    "board_level": board_level,
     "board_check": cfg.get(f"env:{pio_env}", "board_check", default="false").strip().lower() == "true",
   }
   all_envs.append(env)
@@ -52,10 +69,8 @@ for pio_env in pio_envs:
 if "check" in args.platform:
   for env in all_envs:
     if env["board_check"]:
-      if "pr" in args.level:
-        if env["board_level"] == "pr":
-          outlist.append(env["ci"])
-      else:
+      # '--level pr' narrows to the PR subset; otherwise check every level
+      if "pr" not in args.level or env["board_level"] == "pr":
         outlist.append(env["ci"])
 # Filter (non-check) builds by platform
 else:
@@ -67,8 +82,8 @@ else:
       # Include board_level = 'extra' when requested
       elif "extra" in args.level and env["board_level"] == "extra":
         outlist.append(env["ci"])
-      # If no board level is specified, include in release builds (not PR)
-      elif "pr" not in args.level and not env["board_level"]:
+      # Include board_level = 'release' unless narrowed to the PR subset
+      elif "pr" not in args.level and env["board_level"] == "release":
         outlist.append(env["ci"])
 
 # Return as a JSON list