311156 2026-03-30 19:28:41 -0700 REGRESSION (STP 239-240): MediaStreamTrack DataCloneError: The object can not be cloned 2026-04-07 09:50:16 -0700 1 1 1 Unclassified WebKit Media Safari Technology Preview Unspecified Unspecified RESOLVED FIXED InRadar P2 Critical --- 1 bennett.chen youennf ap jer.noble webkit-bug-importer oldest_to_newest 2195395 0 478856 bennett.chen 2026-03-30 19:28:41 -0700 Created attachment 478856 Test MediaStreanTrack Clone In the current preview version(240), MediaStreamTrack does not appear to support structured cloning. When attempting to transfer or clone a track (e.g., via postMessage to a Worker), it throws the following error: DataCloneError: The object can not be cloned 2196054 1 ap 2026-04-01 16:06:31 -0700 Thank you for the report! I cannot reproduce this in STP 240. I get two mirrored videos, and no errors in console. 2196055 2 ap 2026-04-01 16:09:08 -0700 My mistake, I still had STP 239 on this machine. I can reproduce with STP 240. 2196056 3 webkit-bug-importer 2026-04-01 16:09:16 -0700 <rdar://problem/173891803> 2197573 4 youennf 2026-04-07 03:26:04 -0700 Pull request: https://github.com/WebKit/WebKit/pull/62186 2197666 5 ews-feeder 2026-04-07 09:50:14 -0700 Committed 310717@main (3bf2b90a001e): <https://commits.webkit.org/310717@main> Reviewed commits have been landed. Closing PR #62186 and removing active labels. 478856 2026-03-30 19:28:41 -0700 2026-03-30 19:28:41 -0700 Test MediaStreanTrack Clone TestMediaTrack.zip application/zip 3217 bennett.chen UEsDBBQAAAAAAGVSf1wAAAAAAAAAAAAAAAAPACAAVGVzdE1lZGlhVHJhY2svdXgLAAEE9gEAAAQU AAAAVVQNAAcfL8tpSC/LaR8vy2lQSwMEFAAIAAgA41J/XAAAAAAAAAAAAAAAABkAIABUZXN0TWVk aWFUcmFjay9pbmRleC5odG1sdXgLAAEE9gEAAAQUAAAAVVQNAAcLMMtpmjDLaQswy2mdVNuO0zAQ fd+vGIx4YtM0uwtalSQPgOAJWKmF92k8aQyJHdlOswXx7/iSpnvRgoQiOc5czpkZnzh/xlVlDz1B Y7u2PMv9C1qUu4L9bJJ3n5m3EfLyDCDvyCJUDWpDtmBfNx+SawbpySWxo4LtBY290pZBpaQl6UJH wW1TcNqLipLwcQ5CCiuwTUyFLRXZYnmEssK2VK6xRi3gE3GBa6sJu43G6seNVhUZozS8p07laQz2 acYe4g5gq/gBfoUtQO2KSGrsRHtYgUFpEkNa1G8md4d6J+QKLq7622j7HdaFVuOMwYXpW3T5dUu3 x8wd9ivIXvezwTuTUXuzX++i7QUnNcOFCazg6np5Su7wNpns2XL54mjeup53Wg2Sr+B5lmWzXWlO OtHIxWBcysX96ntNM9s9iPqVf44oPXIu5O5u/iPo65NnbISlxPRY0cpTJA/b3A7WKjkzn+Bdo/dG FTlWsHyqnzuTqQbtztsRKuHkpE98eTqdeZ5Gieb+4IMYmuzfAtqQsZOKXLjP6qN8Ng1BS7UF404N TKNGA9bZlBZOKthC5XSuEWoifg4oefA6Z/MoJZ57HzmJw/YQGJ4u6iV88ynB+pGko7FKL0Kzrjr/ nmYseMGMRW3fWsnKtd+FjvI0BsSGnAx8YKt2rHQImiIGF3uoWjSmYE7mLLbtreU087y5LL8c2w0V uSFdzt7YlkfWOAY3Axys8j8J+MUI2QpJ0A2WuGMOCRNNOvM8ZLyZ5/Q3ynma/0s8bcKlUWnRW/A3 YME6xYeWGBhdFWyRdijk4rvxg4thXmhRYa6ycF3+AVBLBwgVzi1gYAIAAD8FAABQSwMEFAAIAAgA 5lJ/XAAAAAAAAAAAAAAAABgAIABUZXN0TWVkaWFUcmFjay93b3JrZXIuanN1eAsAAQT2AQAABBQA AABVVA0ABxEwy2maMMtpETDLaZ1WS4/TMBC+91fM5uRKJQscWxUOK14SKxCs4IA4mGSSWuvaxXZb qm7+O+NHUvexEouVQzSPb95jN2tVOaEVrLR1H3XLlmgtb3EM+xGARdmUnnMbqWwPbrfCKRRSt8UE kjB049moG42CuFY9dQ7c7lQFDDeo3BjmrwJopZV1EJEm4Ayv7qEj4SBV1txxeHiAfTcbkbBogHlB uJrPobCOG1eMwaBbGxUEnNkF1IOobuAWa8G/OoN8eefxPxtdkVPawNzDrFWNjVBYF+OkSzgLo7eg cAtvjNGGFY9jCAtKO+AbLiT/JRGEgu/a3KMpKA8erBudevRN1KgDzjtUaLh7ki+XtP/Hi09NYyuD qG642nD7BA9ONf/Zet9XxQ1l0gnVwmpI5DW0fThlWXrFoBIb5CA2D448Wg/flLGJkuWo3x7yHPQv 5JD1Fs/6PKVhaPfkDNbPgqki9e00CyD5MEmqP044PwO9NyjRQZVqAGot5exAdn8GWhYOgSjbaLPE PqC7nhKTwvraxaEb5NnGB/7W8CVNG2E5o6VEc6h1PkPxRItbUbsF2Trol7WwK8l33wOHhjRjVbrG OjBmZ0gLFO3CXYR6H1kXsCIn5SAe38lXKW2kEf/K6KffD9ver8RJdj0r/o6PwoSsBJTPkxZnAW3S a86OFUORkpkW3Q3lFf84VrysqTf2wOVqwafQcGlx6Mt4ujyi62u4FX7CqPQNjZOqwXhzoyNTpeUb ZEconlpJ5OYLVo49nwB9jzvspUNDSO6wD+z5mYituET27MUEXpzxasO3H5Z+NvJ++hfDBi1NAQ7D lncG5T0g5TMaCCzmdnJSMCfocnF8uZrm/TJQJ0fCqQgFtVrFDRUmr8KZN2kuSlS/17hG1ruWxdMB 7Uku5fG0UA2/IU2QWK60cVy5Kd1PVBoblqL3LRPOu1xqe1TVLv0NO6SRa7tgedMO23QY7yhUDDBJ eYhv0Pjq786wf8UKJe37fsMSLd++fMtFtn2pfLz2Gz7hl179jq6Hdbtg2VIaH/E1O6y/rRHOA5x5 9Ll3BOkGqmMIHQ2Vqxb0ZjDDijp/hfS3VFzO6AdoqG56fUyByK/L/i1CS4HWJIUagA858lmnl8Zf UEsHCEuRGrxEAwAABwkAAFBLAwQUAAgACADhUn9cAAAAAAAAAAAAAAAAFgAgAFRlc3RNZWRpYVRy YWNrL21haW4uanN1eAsAAQT2AQAABBQAAABVVA0ABwYwy2maMMtpBjDLaZ1W227bRhB911eMiT5Q iLxu04cUNNQCSd0iQNMWcS8ProGsl0NpLWpX3V1KERz+e2YvJCWbVi8vugxnzpyZPTNLoZV1YB03 7rVTMIdSi2aNyrEFuqsa/c/X+7dlnnU+2fRyIkKU4bs/ZIn6VFTnM0RtjBZoLZb/GHvsOSDUenFV nwokB+89qRolnNTKR+SMMW4WdgoPE4AEJBUSjjezNd/k185ItZiyey1VnoHHiK66RnaI4e2BBXP4 0b3RylFueDGPiC8g+0tll5P2gIFYolhdN5uNNi4/5GDQNrUjFt4EsMZS8u9xK6nyAs7OFN/KBXfa sMMn3/mSf7do3nnjLETutFmhKcDtN6gr+DP8hbP5HLJGlVgRszKLriGKikW+/s1wsfo1NloP0c96 jAOGAwqOP6JC4/n2UCPP/h2rp1DPepxg9YPhazwmE0zjIb9UlRUGUb3hasttH/fIPhbcelEYdI1R 6VCDArqxYbwsr7Ykk5+kdZ53nolailU2A273SgCpYv5tUEEfUkrL72osSR3ONDiuOiJCWqNHzuyT iKKybFQbORyL7zL4eDlnyeYzusYWWXpWUUfzCHKzmsH2FnwL7u5ROEYpjUSbJ/TpNOWMiB/O4YuH VVvQ57b9kODaSfiSFeRnKexIzQOEWxq9A4U7uDJGU4sOZQ7SgtJ9XdQWqSgCQTTG+E6g2kqjld8D WZ/6SeY4Jydypsn5X9nC18UFvFVwzStu5HktVwhyvYn7iftlYGcn5mvN96BVvYc7BPy40TZmjqRY h3+tYYe0ACNFOhHhKMTg3400lM4RRCC75oE15SnZoTRCZr/6dpycx5fM0Y7Ju3Zt/QQVffdo78jS LQv46uU3X8564xLlYukKePXywFj5uXvPHY3j17257X7wppQEXPHaYrS108vY0O4SYdaIKEOiHmtI Hkmszvfytn/oKxjWj+2kH+QQXE+o4GcdS4XgCDsa+krTxD8665g4aoryeoB4VHnGLqKZ3Vsa8oew SgrI1rpsasyG6pKXl5K1fOFvpBz9pugXwpAooswguc4iu2K4VEOl0BJGgGAldzzliYX7eJj79RVu yYODDBvhJrK5zfocqd5wDmG7df/bcdieynng9jTFexQotyTr3hOS55Dp+Oo/Onff4oPxyW+Oa7/9 r3zRn/ezjYDweKwdcbW0jw8x+IcjNOboAANq2i2mUU7SHRScCwKnH6w7/k+f/N9OZgk/rmtUJb2g gDZyIRWvkzad7tIz1jUxGWh/uHcRN+8VGO6XLGkn6JDygOBOLBPt4Rrxbz6BZT5wilw8SLOheZV0 Q43UEF+mQliKG7vXwrgHAhNP5DNQSwcIapVa9OsDAACPCgAAUEsBAhQDFAAAAAAAZVJ/XAAAAAAA AAAAAAAAAA8AGAAAAAAAAAAAAO1BAAAAAFRlc3RNZWRpYVRyYWNrL3V4CwABBPYBAAAEFAAAAFVU BQABHy/LaVBLAQIUAxQACAAIAONSf1wVzi1gYAIAAD8FAAAZABgAAAAAAAAAAACkgU0AAABUZXN0 TWVkaWFUcmFjay9pbmRleC5odG1sdXgLAAEE9gEAAAQUAAAAVVQFAAELMMtpUEsBAhQDFAAIAAgA 5lJ/XEuRGrxEAwAABwkAABgAGAAAAAAAAAAAAKSBFAMAAFRlc3RNZWRpYVRyYWNrL3dvcmtlci5q c3V4CwABBPYBAAAEFAAAAFVUBQABETDLaVBLAQIUAxQACAAIAOFSf1xqlVr06wMAAI8KAAAWABgA AAAAAAAAAACkgb4GAABUZXN0TWVkaWFUcmFjay9tYWluLmpzdXgLAAEE9gEAAAQUAAAAVVQFAAEG MMtpUEsFBgAAAAAEAAQAbgEAAA0LAAAAAA==