fix(linux): handle ATK C linkage with newer GLib headers by richyo-codes · Pull Request #193942 · flutter/flutter

richyo-codes · 2026-10-07T02:31:07Z

Summary

Fix a Linux engine compilation issue involving ATK C linkage and newer GLib headers while preserving compatibility with the existing Debian Bullseye sysroot.

Older ATK headers do not consistently declare the atk_get_*version functions with C linkage. The existing workaround wraps <atk/atk.h> in extern "C", but newer GLib headers can include C++ support headers. Including those headers inside a C linkage block can cause C++ compilation errors.

Changes

Introduce a shared fl_atk_compat.h compatibility header that includes <glib.h> before wrapping <atk/atk.h> in extern "C".
Replace direct ATK includes and duplicated linkage workarounds in the affected Linux embedder sources and tests.
Register the compatibility header in BUILD.gn.
Avoid version-specific conditionals because distribution backports make header compatibility difficult to infer from GLib or ATK versions alone.

The underlying ATK header issue was fixed upstream in [at-spi2-core MR !219](https://gitlab.gnome.org/GNOME/at-spi2-core/-/merge_requests/219). See also [Debian bug #1145539](https://bugs.debian.org/1145539).

Compatibility and scope

This addresses one compilation issue encountered when preparing Linux engine builds for newer Debian Trixie sysroots, while maintaining compatibility with Bullseye.

Contributes to #194923, which tracks broader Bullseye/Trixie sysroot compatibility.

This PR intentionally does not:

Change the default Linux sysroot.
Modify accessibility behavior or runtime requirements.

The compatibility wrapper can be removed once all supported build environments contain the corrected ATK declarations.

Testing

Bullseye and Trixie sysroot build compatibility validation is tracked in [Linux][Engine] Ensure build compatibility with Bullseye and Trixie sysroots #194923.
No runtime behavior changes are intended.

Pre-launch Checklist

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Centralize the ATK linkage workaround and include C++ type traits outside the C linkage block. Keep GTK4 target selection and accessibility behavior out of this compatibility fix.

Let GLib include its own C++ support headers before entering the external C linkage block required by older ATK version declarations. Avoid depending explicitly on the standard headers GLib happens to use internally. Validated the ATK header and C linkage with Bullseye and Trixie sysroots.

Document the upstream 2.59.0 fix and older-version distribution backports, the reason GLib must load outside C linkage, and the condition for removing the wrapper. A header linkage probe fails without the wrapper for the local Bullseye ATK 2.38 and Trixie ATK 2.55 headers. Fixed host ATK 2.60.7 headers work directly; the GLib-first wrapper works in all three environments.

gemini-code-assist

Code Review

This pull request introduces a new compatibility header, fl_atk_compat.h, to centralize and handle ATK header C-linkage compatibility issues, replacing inline workarounds and direct <atk/atk.h> includes across several Linux platform files. The review feedback identifies multiple violations of the Google C++ Style Guide regarding include ordering, specifically recommending that primary headers be placed first and project headers be grouped and sorted alphabetically.

gemini-code-assist · 2026-10-21T16:23:28Z

-extern "C" {
-#include <atk/atk.h>
-}
+#include "flutter/shell/platform/linux/fl_atk_compat.h"


According to the Google C++ Style Guide, the primary header (fl_accessibility_handler.h) should be the very first include in a test file, and project headers should be grouped and sorted alphabetically.\n\nPlease reorder the includes as follows:\ncpp\n#include "flutter/shell/platform/linux/fl_accessibility_handler.h"\n\n#include "flutter/shell/platform/linux/fl_atk_compat.h"\n#include "flutter/shell/platform/linux/fl_binary_messenger_private.h"\n

References

The Google C++ Style Guide requires the primary header to be the first include, followed by other headers grouped and sorted alphabetically. ^(link)

gemini-code-assist · 2026-10-21T16:23:29Z

-extern "C" {
-#include <atk/atk.h>
-}
+#include "flutter/shell/platform/linux/fl_atk_compat.h"


According to the Google C++ Style Guide, the primary header (fl_view_accessible.h) should be the very first include in the source file, and other project headers should be grouped and sorted alphabetically.\n\nPlease reorder the includes as follows:\ncpp\n#include "flutter/shell/platform/linux/fl_view_accessible.h"\n\n#include "flutter/shell/platform/linux/fl_accessible_node.h"\n#include "flutter/shell/platform/linux/fl_accessible_text_field.h"\n#include "flutter/shell/platform/linux/fl_atk_compat.h"\n

References

The Google C++ Style Guide requires the primary header to be the first include, followed by other headers grouped and sorted alphabetically. ^(link)

gemini-code-assist · 2026-10-21T16:23:29Z


-#include <atk/atk.h>
 #include <gio/gio.h>
+#include "flutter/shell/platform/linux/fl_atk_compat.h"


According to the Google C++ Style Guide, project headers should be grouped together and sorted alphabetically.\n\nPlease reorder the project headers as follows:\ncpp\n#include "flutter/shell/platform/embedder/embedder.h"\n#include "flutter/shell/platform/linux/fl_atk_compat.h"\n#include "flutter/shell/platform/linux/public/flutter_linux/fl_engine.h"\n

References

The Google C++ Style Guide requires project headers to be grouped together and sorted alphabetically. ^(link)

gemini-code-assist · 2026-10-21T16:23:29Z

 #endif

-#include <atk/atk.h>
+#include "flutter/shell/platform/linux/fl_atk_compat.h"


According to the Google C++ Style Guide, project headers should be grouped together and sorted alphabetically.\n\nPlease reorder the project headers as follows:\ncpp\n#include "flutter/shell/platform/embedder/embedder.h"\n#include "flutter/shell/platform/linux/fl_atk_compat.h"\n#include "flutter/shell/platform/linux/public/flutter_linux/fl_engine.h"\n

References

The Google C++ Style Guide requires project headers to be grouped together and sorted alphabetically. ^(link)

fix(linux): handle ATK C linkage with newer GLib headers

91fff42

Centralize the ATK linkage workaround and include C++ type traits outside the C linkage block. Keep GTK4 target selection and accessibility behavior out of this compatibility fix.

github-actions Bot added engine flutter/engine related. See also e: labels. a: accessibility Accessibility, e.g. VoiceOver or TalkBack. (aka a11y) platform-linux Building on or for Linux specifically a: desktop Running on desktop team-linux Owned by the Linux platform team labels Oct 7, 2026

richyo-codes added 2 commits October 6, 2026 23:37

This was referenced Oct 19, 2026

[Linux] Track GTK3 embedder refactors to prepare for GTK4 #194698

Open

[Linux][Engine] Ensure build compatibility with Bullseye and Trixie sysroots #194923

Open

Merge branch 'master' into pr/linux-atk-glib-compat

36a2bce

richyo-codes marked this pull request as ready for review October 21, 2026 16:11

richyo-codes requested a review from a team as a code owner October 21, 2026 16:11

gemini-code-assist Bot reviewed Oct 21, 2026

View reviewed changes

richyo-codes marked this pull request as draft October 29, 2026 19:52

richyo-codes mentioned this pull request Nov 5, 2026

Patch atkversion.h in sysroots to add C linkage declarations #195883

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fix(linux): handle ATK C linkage with newer GLib headers - #193942

fix(linux): handle ATK C linkage with newer GLib headers#193942
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richyo-codes commented Oct 7, 2026 •

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richyo-codes commented Oct 7, 2026 •

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