fix(tokens): fail closed when the vetted token source is missing

The firmware token table is generated by this repository: lib/firmware/
CMakeLists.txt runs ethereum_tokens.py to produce ethereum_tokens.def, and
unittests/firmware/coins.cpp reads the result.

build() checked neither that the vetted ethereum-lists source was present nor
that the scan produced anything. On an ordinary non-recursive checkout every
add_tokens() call returns early, the table serializes zero rows, "0 of 0 kept"
goes to stderr, and the firmware builds green with an empty token table -- the
device would then show raw addresses and unknown decimals for every ERC-20 it
should have recognized. Measured directly: the old path yields 0 tokens and
raises nothing; the guard now raises.

add_tokens() also returned out of the whole scan on the first entry that was
not a regular file, where os.listdir order is arbitrary. That one is latent,
not live: the currently pinned ethereum-lists has no non-file entries in any
scanned directory, and the table is 1378 tokens with or without the change.
It is corrected to `continue` so the hazard cannot arrive with a source bump.

Restores the fail-closed form that already exists on the fork develop line.
Adds the guarding regression test, which fails without this change.

Author: BitHighlander

keepkeylib/eth/ethereum_tokens.py

@@ -29,20 +29,30 @@ def add_tokens(self, network):
             fullpath = os.path.join(dirname, filename)
 
             if not os.path.isfile(fullpath):
-                return
+                continue
 
             with open(fullpath, 'r') as f:
                 token = json.load(f)
 
                 self.tokens.append(ETHToken(token, network))
 
     def build(self):
+        source = HERE + '/ethereum-lists/src/tokens'
+        if not os.path.isdir(source):
+            raise RuntimeError(
+                'vetted ethereum-lists token source is missing; initialize '
+                'submodules recursively before generating firmware tables')
+
         with open(HERE + '/ethereum_networks.json', 'r') as f:
             networks = json.load(f)
 
             for network in networks:
                 self.add_tokens(network)
 
+        if not self.tokens:
+            raise RuntimeError(
+                'vetted ethereum-lists token source produced zero candidates')
+
     def serialize_c(self, outf):
         # Flash budget: this table is the largest read-only symbol in the ARM
         # image. See token_policy for why it is capped rather than complete.

tests/test_token_table_generators.py

@@ -23,6 +23,7 @@
 """
 
 import ast
+import importlib
 import os
 import re
 import subprocess
@@ -58,6 +59,19 @@ def _vetted_source_present():
 
 class TestTokenTableGenerators(unittest.TestCase):
 
+    def test_ethereum_tokens_missing_source_fails_closed(self):
+        """A non-recursive checkout must stop the firmware build, not emit 0 rows."""
+        module = importlib.import_module('keepkeylib.eth.ethereum_tokens')
+        original_here = module.HERE
+        with tempfile.TemporaryDirectory() as tmp:
+            module.HERE = tmp
+            try:
+                with self.assertRaisesRegex(
+                        RuntimeError, 'ethereum-lists token source is missing'):
+                    module.ETHTokenTable().build()
+            finally:
+                module.HERE = original_here
+
     def _run(self, script):
         """Run one generator into a temp file and return its rows."""
         with tempfile.TemporaryDirectory() as tmp: