fix(hooks): exported vars judged only by inherited value

Raw assignment can hide a short resolved secret or read as a
reference when the exported value is the real literal.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

hooks/secret-guard.py

@@ -70,23 +70,22 @@ def env_secrets():
             val = val[1:-1]
         if name in ALLOW_NAMES:
             continue
-        # The inherited environment resolves $-expansions; the raw literal
-        # is the fallback for values the shell never exported. A literal
-        # that is nothing but a $-reference matches the referencing style
-        # itself, so it is never a candidate.
-        resolved = os.environ.get(name) or val
-        candidates = {os.environ.get(name, ""), val} - {
-            v for v in (val,)
-            if re.fullmatch(r"\$\{?[A-Za-z_][A-Za-z0-9_]*\}?", v)
-        }
-        guarded = False
-        for v in candidates:
-            if (len(v) < MIN_LEN or v in ALLOWLIST or plain_url(v)
-                    or v.startswith(("/", "~"))):
-                continue
-            out.setdefault(name, []).append(v)
-            guarded = True
-        if not guarded and 0 < len(resolved) < MIN_LEN:
+        # An exported variable is judged only by its inherited value — the
+        # raw assignment may expand to something else entirely. The raw
+        # literal counts only for never-exported lines, and one that is
+        # nothing but a $-reference matches the referencing style itself,
+        # so it is skipped.
+        if name in os.environ:
+            resolved = os.environ[name]
+        elif re.fullmatch(r"\$\{?[A-Za-z_][A-Za-z0-9_]*\}?", val):
+            continue
+        else:
+            resolved = val
+        if (len(resolved) >= MIN_LEN and resolved not in ALLOWLIST
+                and not plain_url(resolved)
+                and not resolved.startswith(("/", "~"))):
+            out.setdefault(name, []).append(resolved)
+        elif 0 < len(resolved) < MIN_LEN:
             unguardable.append(name)
     return out, unguardable