Rename mktree.podman to mktree.oci

This name is a better fit as it puts more emphasis on the format of the
resulting tree, not as much on the actual container engine used (which
can be swapped, and currently is in the CI where we use docker instead
of podman).

Also drop the awkward .docker symlink now and instead pass the container
engine through the MKTREE_ENGINE environment variable.

.github/workflows/linux.yml

@@ -9,8 +9,11 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Build the Fedora testing environment
-        run: ./mktree.docker build
+        run: ./mktree.oci build
         working-directory: ./tests
       - name: Run the test suite
-        run: ./mktree.docker check --interactive=false -j$(nproc)
+        run: ./mktree.oci check --interactive=false -j$(nproc)
         working-directory: ./tests
+
+    env:
+      MKTREE_ENGINE: docker

tests/CMakeLists.txt

@@ -68,18 +68,18 @@ if (nproc GREATER 1)
 endif()
 
 # Set up mktree
-set(MKTREE_BACKEND podman CACHE STRING "Mktree backend to use")
+set(MKTREE_BACKEND oci CACHE STRING "Mktree backend to use")
 set(DOCKERFILE ${CMAKE_CURRENT_SOURCE_DIR}/Dockerfile.${OS_NAME})
-if (MKTREE_BACKEND STREQUAL podman)
+if (MKTREE_BACKEND STREQUAL oci)
 	find_program(PODMAN podman)
 	find_program(DOCKER docker)
 	mark_as_advanced(PODMAN DOCKER)
 	if (PODMAN AND EXISTS ${DOCKERFILE})
 		set(MKTREE_NATIVE yes)
 		configure_file(${DOCKERFILE} Dockerfile COPYONLY)
 		add_custom_target(ci
-			COMMAND ./mktree.podman build
-			COMMAND ./mktree.podman check ${JOBS} $(TESTOPTS)
+			COMMAND ./mktree.oci build
+			COMMAND ./mktree.oci check ${JOBS} $(TESTOPTS)
 			WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
 		)
 	else()

tests/README.md

@@ -18,7 +18,7 @@ The mode is selected automatically during cmake configuration based on the host
 distribution and the container engine installed, with native mode being
 preferred whenever possible, and is reported in the cmake output as follows:
 
-    -- Using mktree backend: podman (native: <yes|no>)
+    -- Using mktree backend: oci (native: <yes|no>)
 
 Then run the command
 

tests/mktree.podman → tests/mktree.oci

@@ -13,7 +13,7 @@ else
     # Running from source directory
     CMAKE=no
     NATIVE=no
-    PODMAN=$(echo $PROGRAM | cut -d'.' -f2)
+    PODMAN=${MKTREE_ENGINE:-podman}
     CONTEXT=..
 fi