fix(introspection): corrected bitmasks for mutability checks

[rudism]

closes graphile/crystal#1138

[benjie]

Great spot; our logic is the wrong way around.

CMD_UPDATE (2), CMD_INSERT (3) and CMD_DELETE (4) are defined here:

typedef enum CmdType
{
	CMD_UNKNOWN,
	CMD_SELECT,					/* select stmt */
	CMD_UPDATE,					/* update stmt */
	CMD_INSERT,					/* insert stmt */
	CMD_DELETE,
	CMD_UTILITY,				/* cmds like create, destroy, copy, vacuum,
								 * etc. */
	CMD_NOTHING					/* dummy command for instead nothing rules
								 * with qual */
} CmdType;

That's used here to build the bitmap:

			if (trigDesc->trig_insert_instead_row)
				events |= (1 << CMD_INSERT);
			if (trigDesc->trig_update_instead_row)
				events |= (1 << CMD_UPDATE);
			if (trigDesc->trig_delete_instead_row)
				events |= (1 << CMD_DELETE);

So I can confirm that INSERT is the 4th bit (00001000), UPDATE is the 3rd bit (00000100), and DELETE is the 5th bit (00010000).

[benjie]

This bug literally just passed 3 years old, and you had the audacity to squash it?! 😂

graphile/crystal@14f5db7