Crash on iOS 7.1

在Storyboard的一个Controller里添加了FDStackView，用代码dismiss该controller时崩溃在FDStackViewDistributionLayoutArrangement.m第226行：[self.canvas removeConstraints:self.relatedDimensionConstraints.fd_allObjects];
控制台输出：
Objective: {objective 0x178839a40: <999:-18.4039, 998:-342.146, 997:25.7032, 996:-0.509864, 750:826, 251:789, 25:1248> + <750:1, 251:1>_0x1708ad740.negError{id: 1554} + <750:1, 251:1>_0x1708ad7a0.negError{id: 1558} + <750:1, 251:1>_0x1708ad800.negError{id: 1560} + <750:1, 251:1>_0x1708ad8c0.posErrorMarker{id: 1561} + <750:1, 251:1>_0x1708ad920.posErrorMarker{id: 1563} + 750:1_0x1708ad980.negError{id: 1574} + <750:-6.44498e-07, 251:1>_0x1708ad980.posErrorMarker{id: 1573} + <750:1, 25:-2>_0x1708ad9e0.negError{id: 1576} + <251:1, 25:2>_0x1708ad9e0.posErrorMarker{id: 1575} + <750:1, 251:1>_0x1708adb60.negError{id: 1632} + <750:1, 251:1>_0x1708adbc0.negError{id: 1634} + <750:1, 251:1>_0x1708adc20.negError{id: 1636} + <750:1, 251:1>_0x1708adc80.negError{id: 1638} + <750:-2, 251:4>_0x171280320.marker{id: 1262} + <750:-2, 251:4>_0x171280780.marker{id: 1274} + 251:1_0x17128c990.marker{id: 1470} + 51:2_0x17128d3e0:FDSV-spanning-fit.negError{id: 1387} + 999.5:2_0x17128d430:FDSV-spanning-boundary.posErrorMarker{id: 1389} + 999.5:1_0x17128d480:FDSV-spanning-boundary.error{id: 1394} + 999.5:1_0x17128d4d0:FDSV-spanning-boundary.negError{id: 1397} + 999.5:1_0x17128d4d0:FDSV-spanning-boundary.posErrorMarker{id: 1396} + 999.5:1_0x17128d520:FDSV-spanning-boundary.error{id: 1400} + 999.5:2_0x17128d570:FDSV-spanning-boundary.negError{id: 1402} + 999.5:1_0x17128d5c0:FDSV-spanning-boundary.error{id: 1405} + 251:1_0x17128d610.marker{id: 1316} + 999.5:2_0x17128d660:FDSV-spanning-boundary.posErrorMarker{id: 1406} + 251:1_0x17128d930.marker{id: 1318} + 750:-1_0x17128db60.marker{id: 1320} + 251:-1_0x17128dc50.marker{id: 1428} + 251:-1_0x17128dcf0.marker{id: 1434} + 251:-1_0x17128dd90.marker{id: 1439} + 251:-1_0x17128dde0.marker{id: 1441} + 750:0_0x17128de80.marker{id: 1445} + 750:0_0x17128ded0.marker{id: 1447} + 750:1_0x17128df20.marker{id: 1450} + 750:1_0x17128dfc0.marker{id: 1455} + 251:1_0x17128e1f0.marker{id: 1474} + 251:1_0x17128e240.marker{id: 1476} + <750:1, 251:-2>_0x17128e2e0.marker{id: 1478} + <750:1, 251:-2>_0x17128e330.marker{id: 1481} + 750:0_0x1712940a0:FDSV-fill-proportionally.negError{id: 1606} + 750:0_0x171294280:FDSV-fill-proportionally.negError{id: 1610} + 25:2_0x1712946e0:FDSV-ambiguity-suppression.negError{id: 1620} + 25:2_0x1712948c0:FDSV-ambiguity-suppression.negError{id: 1623} + 999.5:1_0x1712949b0:FDSV-alignment.marker{id: 1624} + 25:2_0x171294aa0:FDSV-ambiguity-suppression.negError{id: 1626} + 999.5:-1_0x171294b90:FDSV-alignment.marker{id: 1627} + 25:2_0x171294c80:FDSV-ambiguity-suppression.negError{id: 1629} + 999.5:1_0x171294d70:FDSV-alignment.marker{id: 1630} + <750:-1, 251:2>_0x178a86f90.marker{id: 112} + 999:2_0x178aab760.negError{id: 1507} + 999:2_0x178aab7c0.negError{id: 1510} + <750:1, 251:1>_0x178aac6c0.negError{id: 1556} + 750:1_0x178aac720.negError{id: 1566} + 250:1_0x178aac720.posErrorMarker{id: 1565} + 750:1_0x178aac780.negError{id: 1568} + 250:1_0x178aac780.posErrorMarker{id: 1567} + 750:1_0x178aac8a0.negError{id: 1578} + 250:1_0x178aac8a0.posErrorMarker{id: 1577} + 750:1_0x178aac900.negError{id: 1580} + 250:1_0x178aac900.posErrorMarker{id: 1579} + 750:1_0x178aac960.negError{id: 1582} + 251:1_0x178aac960.posErrorMarker{id: 1581} + <750:1, 25:-2>_0x178aac9c0.negError{id: 1584} + <251:1, 25:2>_0x178aac9c0.posErrorMarker{id: 1583} + 750:1_0x178aaca20.negError{id: 1586} + <750:0, 251:1>_0x178aaca20.posErrorMarker{id: 1585} + <750:1, 25:-2>_0x178aaca80.negError{id: 1588} + <251:1, 25:2>_0x178aaca80.posErrorMarker{id: 1587} + 750:1_0x178aacae0.negError{id: 1590} + 250:1_0x178aacae0.posErrorMarker{id: 1589} + 750:1_0x178aacb40.negError{id: 1592} + 250:1_0x178aacb40.posErrorMarker{id: 1591} + 750:1_0x178aacba0.negError{id: 1594} + <750:0, 251:1>_0x178aacba0.posErrorMarker{id: 1593} + <750:1, 25:-2>_0x178aacc00.negError{id: 1596} + <251:1, 25:2>_0x178aacc00.posErrorMarker{id: 1595} + <750:-2, 251:4>_0x179283020.marker{id: 1305} + 251:1_0x179289650.marker{id: 1473} + 999.5:1_0x179289dd0:FDSV-spanning-boundary.error{id: 1410} + 999.5:2_0x179289e20:FDSV-spanning-boundary.negError{id: 1412} + 999.5:1_0x179289e70:FDSV-spanning-boundary.error{id: 1415} + 25:2_0x179289fb0:FDSV-ambiguity-suppression.negError{id: 1337} + 25:2_0x17928a050:FDSV-ambiguity-suppression.negError{id: 1340} + 25:2_0x17928a0f0:FDSV-ambiguity-suppression.negError{id: 1350} + 25:2_0x17928a190:FDSV-ambiguity-suppression.negError{id: 1353} + <750:-1, 251:2>_0x17928a5a0.marker{id: 1519} + 750:0_0x179290680:FDSV-canvas-connection.marker{id: 1597} + 750:0_0x1792906d0.marker{id: 1598} + <750:-2, 251:4>_0x1792920c0.marker{id: 1688} + 750:0_{id: 148} + 750:0_{id: 179} + 750:0_{id: 186} + 750:6.37025e-07_{id: 187} + 750:0_{id: 420} + 750:0_{id: 424} + 51:1_FDLayoutSpacer:0x178588470.Width{id: 1388} + 750:0_UIImageView:0x1703eb600.Width{id: 1334} + 750:0_UIImageView:0x1703eba00.minX{id: 1370} + 750:0_UIImageView:0x1783ecc00.minX{id: 1372} + 750:0_UIImageView:0x1783ecf00.minX{id: 1375} + 999:1__UILayoutGuide:0x178588540.Width{id: 1508} + 999:1*_UILayoutGuide:0x178588610.Width{id: 1511}}

Bắt đầu với FDStackViewDistributionLayoutArrangement.m tại dòng 226 và tái hiện trường hợp được báo cáo: một FDStackView được thêm vào trong một controller của storyboard và bị dismiss bằng code trên iOS 7.1. Kiểm tra đường đi xóa constraint và sử dụng output của console được cung cấp để xác định lý do crash xảy ra. Hoàn tất khi việc dismiss controller không còn gây crash trong cấu hình được báo cáo.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.