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Python tests lose every result when the solution returns inf or NaN

Abierto Apto para principiantes
  • ¿Algo no está bien?
#419 0 comentarios 0 reacciones 0 asignados Ver en GitHub

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Evaluación

Dificultad
2/5
Tiempo estimado
1-3 horas
Aptitud para principiantes
77/100
Tipo de issue
Error
Claridad
Bien especificado
Estado de actividad
Activo
Stack tecnológico
javascript, python, rust
Área
backend, testing

Línea de trabajo

Empieza con el ejecutor de Python en web/runners.js y reproduce el problema usando el código fuente de pythonDriver con la entrada coin-change de problem-bank/judges.json. Compara cómo maneja los resultados no finitos con los ejecutores de JavaScript y Java citados en el issue. Se considera terminado cuando solo fallan los casos que devuelven inf o nan y se conservan los resultados de los demás casos.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

Observed behavior

When a Python solution returns float("inf") or float("nan") for any test case, the whole run is reported as a setup error and every case result is lost, including the passing ones. The test panel shows "Couldn't run your code" and a JSON parser message instead of a per-case table. The solution below is wrong for two cases, which is expected; the problem is how the run reports it.

The JavaScript and Java runners fail only the affected case (web/runners.js:517, web/compiler-explorer.js:695). Returning inf for "impossible" is a common mistake that the pitfalls entry of coin-change lists ("returning a large sentinel instead of -1").

The other runners handle the same value per case: the JavaScript Worker's sanitize (web/runners.js:517) turns Infinity into null, and the Java harness's json(double) (web/compiler-explorer.js:695) writes null for a non-finite value, so each of those fails only the affected case.

Expected behavior

Only the cases that returned a non-finite number fail, with their got shown, and the other cases keep their results, as in the JavaScript and Java runners. For the solution below that is 3 passing cases and 2 failing ones ("impossible amount" and "large token ignored", which expect -1).

Reproduction
  1. Start an interview on coin-change (Kiosk Token Payout) and choose Python.
  2. Replace the starter with:
class Solution:
    def fewestTokens(self, tokens: list[int], amount: int) -> int:
        dp = [float("inf")] * (amount + 1)
        dp[0] = 0
        for a in range(1, amount + 1):
            for t in tokens:
                if t <= a:
                    dp[a] = min(dp[a], dp[a - t] + 1)
        return dp[amount]
  1. Click Run tests.
  2. The test results panel shows "Couldn't run your code" and the JSON.parse message below instead of the per-case results.

Without a browser, the same result can be seen by running the pythonDriver source from web/runners.js under CPython 3 with this solution and the coin-change entry of problem-bank/judges.json (with entry set to fewestTokens for the variant). Its output is:

{"results": [{"actual": 3, ...}, {"actual": Infinity, ...}, {"actual": 0, ...}, {"actual": 2, ...}, {"actual": Infinity, ...}]}

Passing that string to JSON.parse throws SyntaxError: Unexpected token 'I'.

CodeTrial version

codetrial 0.1.0 (e9851ab)

Environment

OS: Windows 11
Browser: Google Chrome 153.0.8010.54
Access: local server at http://127.0.0.1:3000/
Language: Python
Problem: coin-change (Kiosk Token Payout variant)

Sanitized evidence

Test results panel:

Couldn't run your code
Unexpected token 'I', ...""actual": Infinity, "... is not valid JSON
Public data confirmation
  • I removed credentials, session tokens, candidate recordings, and personal interview content from this public report.
Lenguaje dominante
Rust
Estrellas
177
Forks
100
Merge medio
1 d 9 h
PR fusionados (30 d)
151

Preparar el entorno

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

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