[PATCH v3 18/19] rv/rvgen: fix unbound loop variable warning

[Wander Lairson Costa <wander@redhat.com>]

Pyright static analysis reports a "possibly unbound variable" warning
for the loop variable `i` in the `abbreviate_atoms` function. The
variable is accessed after the inner loop terminates to slice the atom
string. While the loop logic currently ensures execution, the analyzer
flags the reliance on the loop variable persisting outside its scope.

Refactor the prefix length calculation into a nested `find_share_length`
helper function. This encapsulates the search logic and uses explicit
return statements, ensuring the length value is strictly defined. This
satisfies the type checker and improves code readability without
altering the runtime behavior.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
---
 tools/verification/rvgen/rvgen/ltl2k.py | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/tools/verification/rvgen/rvgen/ltl2k.py b/tools/verification/rvgen/rvgen/ltl2k.py
index b6300c38154dc..b8ac584fe2504 100644
--- a/tools/verification/rvgen/rvgen/ltl2k.py
+++ b/tools/verification/rvgen/rvgen/ltl2k.py
@@ -44,13 +44,17 @@ def abbreviate_atoms(atoms: list[str]) -> list[str]:
         skip = ["is", "by", "or", "and"]
         return '_'.join([x[:2] for x in s.lower().split('_') if x not in skip])
 
-    abbrs = []
-    for atom in atoms:
+    def find_share_length(atom: str) -> int:
         for i in range(len(atom), -1, -1):
             if sum(a.startswith(atom[:i]) for a in atoms) > 1:
-                break
-        share = atom[:i]
-        unique = atom[i:]
+                return i
+        return 0
+
+    abbrs = []
+    for atom in atoms:
+        share_len = find_share_length(atom)
+        share = atom[:share_len]
+        unique = atom[share_len:]
         abbrs.append((shorten(share) + shorten(unique)))
     return abbrs
 
-- 
2.53.0