Avoid reentrancy issues when dropping AppHost, even harder #19395
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The previous fix in #19296 moved the _destruction_ of AppHost into the tail end after we manipulate the `_windows` vector; however, it kept the part which calls into XAML (`Close`) before the `erase`. I suspect that we still had some reentrancy issues, where we cached an iterator before the list was modified by another window close event. That is: ```mermaid sequenceDiagram Emperor->>Emperor: Close Window Emperor->>+AppHost: Close (a) AppHost->>XAML: Close XAML-->>Emperor: pump loop Emperor->>Emperor: Close Window Emperor->>+AppHost: Close (b) AppHost->>XAML: Close XAML-->>Emperor: pump loop AppHost->>-Emperor: Closed Emperor->>Emperor: erase(b) AppHost->>-Emperor: Closed Emperor->>Emperor: erase(a) ``` Moving the `Close()` to after the `erase` ensures that there are no cached iterators that survive beyond XAML pumping the message loop. Fixes 8d41ace
carlos-zamora
approved these changes
Sep 29, 2025
DHowett
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Oct 8, 2025
The previous fix in #19296 moved the _destruction_ of AppHost into the tail end after we manipulate the `_windows` vector; however, it kept the part which calls into XAML (`Close`) before the `erase`. I suspect that we still had some reentrancy issues, where we cached an iterator before the list was modified by another window close event. That is: ```mermaid sequenceDiagram Emperor->>Emperor: Close Window Emperor->>+AppHost: Close (a) AppHost->>XAML: Close XAML-->>Emperor: pump loop Emperor->>Emperor: Close Window Emperor->>+AppHost: Close (b) AppHost->>XAML: Close XAML-->>Emperor: pump loop AppHost->>-Emperor: Closed Emperor->>Emperor: erase(b) AppHost->>-Emperor: Closed Emperor->>Emperor: erase(a) ``` Moving the `Close()` to after the `erase` ensures that there are no cached iterators that survive beyond XAML pumping the message loop. Fixes 8d41ace (cherry picked from commit 5976de1) Service-Card-Id: PVTI_lADOAF3p4s4AxadtzgfScoo Service-Version: 1.23
DHowett
added a commit
that referenced
this pull request
Oct 8, 2025
The previous fix in #19296 moved the _destruction_ of AppHost into the tail end after we manipulate the `_windows` vector; however, it kept the part which calls into XAML (`Close`) before the `erase`. I suspect that we still had some reentrancy issues, where we cached an iterator before the list was modified by another window close event. That is: ```mermaid sequenceDiagram Emperor->>Emperor: Close Window Emperor->>+AppHost: Close (a) AppHost->>XAML: Close XAML-->>Emperor: pump loop Emperor->>Emperor: Close Window Emperor->>+AppHost: Close (b) AppHost->>XAML: Close XAML-->>Emperor: pump loop AppHost->>-Emperor: Closed Emperor->>Emperor: erase(b) AppHost->>-Emperor: Closed Emperor->>Emperor: erase(a) ``` Moving the `Close()` to after the `erase` ensures that there are no cached iterators that survive beyond XAML pumping the message loop. Fixes 8d41ace (cherry picked from commit 5976de1) Service-Card-Id: PVTI_lADOAF3p4s4BBcTlzgfScpM Service-Version: 1.24
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The previous fix in #19296 moved the destruction of AppHost into the tail end after we manipulate the
_windowsvector; however, it kept the part which calls into XAML (Close) before theerase. I suspect that we still had some reentrancy issues, where we cached an iterator before the list was modified by another window close event.That is:
Moving the
Close()to after theeraseensures that there are no cached iterators that survive beyond XAML pumping the message loop.Fixes 8d41ace