import re
from io import StringIO

field_pattern = re.compile(r'(?<=(?<!\S)\{)[^}]*(?=\}(?!\S))|(?<!\S)(?!\{)\S+(?!\S)')
file = StringIO('''\
commit file before after
{./SonarSource-sonarqube/592397657f44ebb8869159e86087fa62f2c64dd0} {QGChangeEventListenersImplTest.java} 0.2554725331856924 0.25835876057253165
{./SonarSource-sonarqube/51ae2098d531a72c7a7136a4da1063fe05a2bc0e} {SearchAction.java} 0.6027389261871576 0.5584944983323415
{./SonarSource-sonarqube/22600d84f370f18b3050e2e06eec9d9975117487} {IssueQueryTest.java} 0.2875728372794886 0.2879662721728285
''')
next(file)
for fields in map(field_pattern.findall, file):
    print(fields)