Documentation/usage mismatch in CFE ES "Start App" command

[jphickey]

Describe the bug
The CFE_PLATFORM_ES_DEFAULT_STACK_SIZE is documented as being a default stack size, not a minimum stack size. But the CFE ES "Start App" command enforces it as a minimum value here:

cFE/fsw/cfe-core/src/es/cfe_es_task.c

Lines 900 to 906 in 9804b59

	else if (cmd->StackSize < CFE_PLATFORM_ES_DEFAULT_STACK_SIZE)
	{
	CFE_ES_TaskData.CommandErrorCounter++;
	CFE_EVS_SendEvent(CFE_ES_START_STACK_ERR_EID, CFE_EVS_EventType_ERROR,
	"CFE_ES_StartAppCmd: Stack size is less than system Minimum: %d.",
	CFE_PLATFORM_ES_DEFAULT_STACK_SIZE);
	}

But this is not in agreement with how it is documented:

cFE/cmake/sample_defs/cpu1_platform_cfg.h

Lines 1186 to 1201 in 9804b59

	/**
	** \cfeescfg Define Default Stack Size for an Application
	**
	** \par Description:
	** This parameter defines a default stack size. This parameter is used by the
	** cFE Core Applications.
	**
	** \par Limits
	** There is a lower limit of 2048. There are no restrictions on the upper limit
	** however, the maximum stack size size is system dependent and should be verified.
	** Most operating systems provide tools for measuring the amount of stack used by a
	** task during operation. It is always a good idea to verify that no more than 1/2
	** of the stack is used.
	*/
	#define CFE_PLATFORM_ES_DEFAULT_STACK_SIZE 8192

To Reproduce
N/A

Expected behavior
Should not enforce the default as a minimum.

I don't see any CFE platform definition for an enforced minimum stack size. If I remember correctly this was discussed once or twice and the agreement was that this is an operational issue - stack size requirements depend on the app stack usage and the memory constraints of the platform - so CFE cannot (and should not) impose some random limitations on it - it should attempt to do what the user requested.

So recommendation would be to remove this check.
One valid possibility is that if the stack size is specified as 0 (which is definitely not valid), to use the default value instead.

System observed on:
Ubuntu 20.04

Reporter Info
Joseph Hickey, Vantage Systems, Inc.

[skliper]

One valid possibility is that if the stack size is specified as 0 (which is definitely not valid), to use the default value instead.

I like this, agreed on don't force as min.