bme280 sample does not compile

[mbolivar]

Describe the bug
The https://docs.zephyrproject.org/latest/samples/sensor/bme280/README.html build instructions do not build. The recommended board (nrf52840_pca10056) doesn't have that sensor in its DTS, so the reason why is clear, but all in-tree samples should compile.

I am unable to find a board in tree which does have this sensor in its DTS.

It's not clear to me whether or how mainline CI is building this sample. It seems like the fixture restriction is bypassing it:

sanitycheck -vv -T samples/sensor/bme280/ -p nrf52840_pca10056
...
DEBUG   - nrf52840_pca10056         samples/sensor/bme280/sample.sensor.bme280         SKIPPED: No hardware support
DEBUG   - nrf52840_pca10056         samples/sensor/bme280/sample.sensor.bme280.spi     SKIPPED: No hardware support

To Reproduce
Steps to reproduce the behavior:

1. cd zephyr
2. west build -b nrf52840_pca10056 samples/sensor/bme280
3. observe build error

In file included from /home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.c:24:0:
/home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.h:114:2: error: #error "BME280 device type not specified"
 #error "BME280 device type not specified"
  ^~~~~
/home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.c: In function 'bme280_init':
/home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.c:370:22: warning: unused variable 'data' [-Wunused-variable]
  struct bme280_data *data = dev->driver_data;
                      ^~~~
In file included from ../include/drivers/sensor.h:23:0,
                 from /home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.c:11:
/home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.c: At top level:
/home/mbolivar/zp/zephyr/drivers/sensor/bme280/bme280.c:398:29: error: 'DT_INST_0_BOSCH_BME280_LABEL' undeclared here (not in a function); did you mean 'DT_INST_0_SOC_NV_FLASH_LABEL'?
 DEVICE_AND_API_INIT(bme280, DT_INST_0_BOSCH_BME280_LABEL, bme280_init, &bme280_data,
                             ^
../include/device.h:106:11: note: in definition of macro 'DEVICE_AND_API_INIT'
   .name = drv_name, .init = (init_fn),     \
           ^~~~~~~~

Expected behavior
Following build instructions for built-in samples should not result in compile errors.

Environment (please complete the following information):

• Commit SHA or Version used: today's master (b96477d)

[nashif]

is this really a high prio bug?

[jhedberg]

is this really a high prio bug?

Well, a non-building sample in the tree was something we decided we want fixed before the release (doesn't really matter what the priority is, but setting high forces it to be done). This was at least the consensus in yesterday's release meeting.

[nashif]

doesn't really matter what the priority is, but setting high forces it to be done

This is bad, high priority bugs should really be reserved to bugs that are more critical than a sample that does not build due to some missing overlay...