Setting highest valid message ID's to 0xFFFF hangs cfe

[skliper]

Describe the bug
Given max number of message keys is 1+ highest valid msgid:

cFE/fsw/cfe-core/src/sb/cfe_sb_priv.h

Line 107 in 95f34d2

#define CFE_SB_MAX_NUMBER_OF_MSG_KEYS (1+CFE_PLATFORM_SB_HIGHEST_VALID_MSGID)

and message key is uint16:

cFE/fsw/cfe-core/src/sb/cfe_sb_priv.h

Line 122 in 95f34d2

typedef uint16 CFE_SB_MsgKey_Atom_t;

Setting CFE_PLATFORM_SB_HIGHEST_VALID_MSGID to 0xFFFF results in forever loop in:

cFE/fsw/cfe-core/src/sb/cfe_sb_init.c

Lines 219 to 224 in 95f34d2

	CFE_SB_MsgKey_Atom_t KeyVal;
	for (KeyVal=0; KeyVal < CFE_SB_MAX_NUMBER_OF_MSG_KEYS; KeyVal++)
	{
	CFE_SB.MsgMap[KeyVal] = CFE_SB_INVALID_ROUTE_IDX;
	}

To Reproduce
Set CFE_PLATFORM_SB_HIGHEST_VALID_MSGID to 0xFFFF and build/run.

Expected behavior
Full 16 bits of message id should be usable.

Code snips
See above

System observed on:

• Hardware: cFS Dev 3
• OS: Ubuntu 18.04
• Versions: master bundle

Additional context
None

Reporter Info
Jacob Hageman - NASA/GSFC (per JSC identification of the issue)