Fix(uart): no global serial creates linking error#12412
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NO_GLOBAL_SERIAL may be defined and hal_uart_notify_pins_detached() may not exist creating problems with the linker.
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Area: UART
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Pull request overview
Fixes a link failure when building without global Serial instances by making the UART “pins detached” notifier optional (weak) and guarding its invocation.
Changes:
- Declares
hal_uart_notify_pins_detached()as a weak symbol in the UART HAL header. - Removes the non-weak prototype from the C file to avoid undefined references.
- Guards notifier calls in RX/TX detach paths to safely no-op when not implemented.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| cores/esp32/esp32-hal-uart.h | Declares the optional notifier as a weak symbol so missing implementations don’t break linking. |
| cores/esp32/esp32-hal-uart.c | Calls the notifier only when present, preventing link errors when Serial globals are disabled. |
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SuGlider
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Feb 26, 2026
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SuGlider
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Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.
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Test Results101 files 101 suites 31m 26s ⏱️ Results for commit c09954f. ♻️ This comment has been updated with latest results. |
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Memory usage test (comparing PR against master branch)The table below shows the summary of memory usage change (decrease - increase) in bytes and percentage for each target.
Click to expand the detailed deltas report [usage change in BYTES]
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lucasssvaz
previously approved these changes
Feb 28, 2026
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Looks good. Please take a look at the copilot comments
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
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Author
I'll change the way it is done.... not using Serial0, Serial1, Serial2, etc. This will solve the issue for any case for good. |
Added functions to register and unregister HardwareSerial objects, allowing for better management of UART instances.
Removed weak prototype for hal_uart_notify_pins_detached function.
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Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.
Comments suppressed due to low confidence (1)
cores/esp32/HardwareSerial.cpp:179
- The early
returnin the destructor when_uart_nr >= SOC_UART_NUMskips freeing_lock(and any other teardown after this block). Since the constructor may have created_lockeven for an invalid UART number, this can leak the semaphore. Consider removing the early return and instead conditionally skipping only the UART-specificend()/uart_unregister()parts, while still deleting_lockwhen present.
HardwareSerial::~HardwareSerial() {
if (_uart_nr >= SOC_UART_NUM) {
return;
}
end(); // explicit Full UART termination
uart_unregister(_uart_nr);
#if !CONFIG_DISABLE_HAL_LOCKS
if (_lock != NULL) {
vSemaphoreDelete(_lock);
}
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Pull request overview
Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.
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Pull request overview
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me-no-dev
approved these changes
Mar 4, 2026
lucasssvaz
approved these changes
Mar 4, 2026
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Status: Pending Merge
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@SuGlider please fix the conflict |
Collaborator
Author
Done. |
|
Whoops, looks like a |
SuGlider
commented
Mar 7, 2026
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Description of Change
If an Arduino Sketch if compiled with NO_GLOBAL_INSTANCES or NO_GLOBAL_SERIAL defined, it will fail with a linking error:
Test Scenarios
Compile any Serial exemple adding the build_opt.h file with
-DNO_GLOBAL_INSTANCESoptionbuild_opt.h file:
Testing Sketch:
Related links
related to #12402