This makes very good sense to me, thank you for taking your time to fix it.
I am slightly unsure whether if checks with subsequent assertions are really needed in mandatory version, as asserting in the constructor will trigger missing protocol very early anyway, but I do not think it is important.

Best wishes,
Vitaly

On Wed, Dec 18, 2019 at 05:10, Zhichao Gao <zhichao.gao@intel.com> wrote:

> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2298
>
> The UefiDevicePathLibOptionalDevicePathProtocolConstructor's implementation
> isn't match with its instance name.
> Remove the ASSERT and depex of the gEfiDevicePathUtilitiesProtocolGuid
> because of "Optional".
>
> Add a mandatory instance to force using the DevicePathUtilities,
> DevicePathToText and DevicePathFromText protocol with the ASSERT
> and depex.
>
> V2:
> The optional lib instance's construction should return success all the
> time.
> Change the desciption of the optional lib uni file.
> Change the copyright date of the mandatory one's uni file.
>
> V3:
> Remove the Status variable in UefiDevicePathLibOptionalDevicePathProtocolConstructor.
> The Status would cause GCC build fail because the variable is initialized but not used.
> Since it is useless for the constructor, directly remove it.
>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Vitaly Cheptsov <vit9696@protonmail.com>
> Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
>
> Zhichao Gao (2):
> MdePkg/UefiDevicePathLib: Separate the device path lib
> MdePkg/dsc: Add UefiDevicePathLibMandatoryDevicePathProtocol for build
>
> ...DevicePathLibMandatoryDevicePathProtocol.c | 469 ++++++++++++++++++
> ...vicePathLibMandatoryDevicePathProtocol.inf | 86 ++++
> ...vicePathLibMandatoryDevicePathProtocol.uni | 18 +
> ...iDevicePathLibOptionalDevicePathProtocol.c | 21 +-
> ...evicePathLibOptionalDevicePathProtocol.inf | 5 +-
> ...evicePathLibOptionalDevicePathProtocol.uni | 6 +-
> MdePkg/MdePkg.dsc | 3 +-
> 7 files changed, 587 insertions(+), 21 deletions(-)
> create mode 100644 MdePkg/Library/UefiDevicePathLib/UefiDevicePathLibMandatoryDevicePathProtocol.c
> create mode 100644 MdePkg/Library/UefiDevicePathLib/UefiDevicePathLibMandatoryDevicePathProtocol.inf
> create mode 100644 MdePkg/Library/UefiDevicePathLib/UefiDevicePathLibMandatoryDevicePathProtocol.uni
>
> --
> 2.21.0.windows.1