feat: checkout to default branch in case of switch back failures

src/Git.cmake

@@ -465,8 +465,19 @@ function(git_switch_back)
  message(STATUS "Switch back failed. Trying to checkout previous branch")
  execute_process(
  COMMAND "${GIT_EXECUTABLE}" "checkout" "-" WORKING_DIRECTORY "${_fun_REPOSITORY_PATH}"
-  COMMAND_ERROR_IS_FATAL LAST
+ RESULT_VARIABLE _checkout_result
  )
+
+ # if the checkout failed, try to checkout the default branch
+ if(NOT ${_checkout_result} EQUAL 0)
+ message(STATUS "Checkout previous branch failed. Trying to checkout default branch")
+ git_default_branch(default_branch REPOSITORY_PATH "${_fun_REPOSITORY_PATH}")
+ execute_process(
+ COMMAND "${GIT_EXECUTABLE}" "checkout" "${default_branch}"
+ WORKING_DIRECTORY "${_fun_REPOSITORY_PATH}" COMMAND_ERROR_IS_FATAL LAST
+ )
+ endif()
+
  endif()
  endif()
 endfunction()
@@ -512,3 +523,56 @@ function(git_wait)
  endif()
  endwhile()
 endfunction()
+
+#[[.rst:
+
+``git_default_branch``
+======================
+Get the default branch of the given repository. Defaults to master in case of failure
+
+Input variables:
+- ``REPOSITORY_PATH``: The path to the repository
+
+Output variables:
+- ``default_branch``: The variable to store the default branch in
+
+
+.. code:: cmake
+
+ git_default_branch(
+ REPOSITORY_PATH
+ "$ENV{HOME}/vcpkg"
+ default_branch
+ )
+
+]]
+function(git_default_branch default_branch)
+ # use git symbolic-ref refs/remotes/origin/HEAD to get the default branch
+
+ set(oneValueArgs REPOSITORY_PATH)
+ cmake_parse_arguments(_fun "" "${oneValueArgs}" "" ${ARGN})
+
+ if("${_fun_REPOSITORY_PATH}" STREQUAL "")
+ message(FATAL_ERROR "REPOSITORY_PATH is required")
+ endif()
+
+ find_program(GIT_EXECUTABLE "git" REQUIRED)
+ execute_process(
+ COMMAND "${GIT_EXECUTABLE}" "symbolic-ref" "refs/remotes/origin/HEAD"
+ OUTPUT_VARIABLE _default_branch
+ WORKING_DIRECTORY "${_fun_REPOSITORY_PATH}"
+ OUTPUT_STRIP_TRAILING_WHITESPACE
+ RESULT_VARIABLE _default_branch_result
+ )
+
+ if(${_default_branch_result} EQUAL 0)
+ string(REGEX REPLACE "refs/remotes/origin/" "" _default_branch "${_default_branch}")
+ else()
+ message(
+ WARNING "Could not get default branch of ${_fun_REPOSITORY_PATH}. Considering it as master"
+ )
+ set(_default_branch "master")
+ endif()
+
+ set(${default_branch} ${_default_branch} PARENT_SCOPE)
+endfunction()