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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
cmake_minimum_required(VERSION 3.5)
function(get_hash_for_ref ref out_var err_var)
execute_process(
COMMAND "@git_EXECUTABLE@" rev-parse "${ref}^{commit}"
WORKING_DIRECTORY "@work_dir@"
RESULT_VARIABLE error_code
OUTPUT_VARIABLE ref_hash
ERROR_VARIABLE error_msg
OUTPUT_STRIP_TRAILING_WHITESPACE
)
if(error_code)
set(${out_var} "" PARENT_SCOPE)
else()
set(${out_var} "${ref_hash}" PARENT_SCOPE)
endif()
set(${err_var} "${error_msg}" PARENT_SCOPE)
endfunction()
get_hash_for_ref(HEAD head_sha error_msg)
if(head_sha STREQUAL "")
message(FATAL_ERROR "Failed to get the hash for HEAD:\n${error_msg}")
endif()
execute_process(
COMMAND "@git_EXECUTABLE@" show-ref "@git_tag@"
WORKING_DIRECTORY "@work_dir@"
OUTPUT_VARIABLE show_ref_output
)
if(show_ref_output MATCHES "^[a-z0-9]+[ \\t]+refs/remotes/")
# Given a full remote/branch-name and we know about it already. Since
# branches can move around, we always have to fetch.
set(fetch_required YES)
set(checkout_name "@git_tag@")
elseif(show_ref_output MATCHES "^[a-z0-9]+[ \\t]+refs/tags/")
# Given a tag name that we already know about. We don't know if the tag we
# have matches the remote though (tags can move), so we should fetch.
set(fetch_required YES)
set(checkout_name "@git_tag@")
# Special case to preserve backward compatibility: if we are already at the
# same commit as the tag we hold locally, don't do a fetch and assume the tag
# hasn't moved on the remote.
# FIXME: We should provide an option to always fetch for this case
get_hash_for_ref("@git_tag@" tag_sha error_msg)
if(tag_sha STREQUAL head_sha)
message(VERBOSE "Already at requested tag: ${tag_sha}")
return()
endif()
elseif(show_ref_output MATCHES "^[a-z0-9]+[ \\t]+refs/heads/")
# Given a branch name without any remote and we already have a branch by that
# name. We might already have that branch checked out or it might be a
# different branch. It isn't safe to use a bare branch name without the
# remote, so do a fetch and replace the ref with one that includes the remote.
set(fetch_required YES)
set(checkout_name "@git_remote_name@/@git_tag@")
else()
get_hash_for_ref("@git_tag@" tag_sha error_msg)
if(tag_sha STREQUAL head_sha)
# Have the right commit checked out already
message(VERBOSE "Already at requested ref: ${tag_sha}")
return()
elseif(tag_sha STREQUAL "")
# We don't know about this ref yet, so we have no choice but to fetch.
# We deliberately swallow any error message at the default log level
# because it can be confusing for users to see a failed git command.
# That failure is being handled here, so it isn't an error.
set(fetch_required YES)
set(checkout_name "@git_tag@")
if(NOT error_msg STREQUAL "")
message(VERBOSE "${error_msg}")
endif()
else()
# We have the commit, so we know we were asked to find a commit hash
# (otherwise it would have been handled further above), but we don't
# have that commit checked out yet
set(fetch_required NO)
set(checkout_name "@git_tag@")
if(NOT error_msg STREQUAL "")
message(WARNING "${error_msg}")
endif()
endif()
endif()
if(fetch_required)
message(VERBOSE "Fetching latest from the remote @git_remote_name@")
execute_process(
COMMAND "@git_EXECUTABLE@" fetch --tags --force "@git_remote_name@"
WORKING_DIRECTORY "@work_dir@"
COMMAND_ERROR_IS_FATAL ANY
)
endif()
set(git_update_strategy "@git_update_strategy@")
if(git_update_strategy STREQUAL "")
# Backward compatibility requires REBASE as the default behavior
set(git_update_strategy REBASE)
endif()
if(git_update_strategy MATCHES "^REBASE(_CHECKOUT)?$")
# Asked to potentially try to rebase first, maybe with fallback to checkout.
# We can't if we aren't already on a branch and we shouldn't if that local
# branch isn't tracking the one we want to checkout.
execute_process(
COMMAND "@git_EXECUTABLE@" symbolic-ref -q HEAD
WORKING_DIRECTORY "@work_dir@"
OUTPUT_VARIABLE current_branch
OUTPUT_STRIP_TRAILING_WHITESPACE
# Don't test for an error. If this isn't a branch, we get a non-zero error
# code but empty output.
)
if(current_branch STREQUAL "")
# Not on a branch, checkout is the only sensible option since any rebase
# would always fail (and backward compatibility requires us to checkout in
# this situation)
set(git_update_strategy CHECKOUT)
else()
execute_process(
COMMAND "@git_EXECUTABLE@" for-each-ref "--format='%(upstream:short)'" "${current_branch}"
WORKING_DIRECTORY "@work_dir@"
OUTPUT_VARIABLE upstream_branch
OUTPUT_STRIP_TRAILING_WHITESPACE
COMMAND_ERROR_IS_FATAL ANY # There is no error if no upstream is set
)
if(NOT upstream_branch STREQUAL checkout_name)
# Not safe to rebase when asked to checkout a different branch to the one
# we are tracking. If we did rebase, we could end up with arbitrary
# commits added to the ref we were asked to checkout if the current local
# branch happens to be able to rebase onto the target branch. There would
# be no error message and the user wouldn't know this was occurring.
set(git_update_strategy CHECKOUT)
endif()
endif()
elseif(NOT git_update_strategy STREQUAL "CHECKOUT")
message(FATAL_ERROR "Unsupported git update strategy: ${git_update_strategy}")
endif()
# Check if stash is needed
execute_process(
COMMAND "@git_EXECUTABLE@" status --porcelain
WORKING_DIRECTORY "@work_dir@"
RESULT_VARIABLE error_code
OUTPUT_VARIABLE repo_status
)
if(error_code)
message(FATAL_ERROR "Failed to get the status")
endif()
string(LENGTH "${repo_status}" need_stash)
# If not in clean state, stash changes in order to be able to perform a
# rebase or checkout without losing those changes permanently
if(need_stash)
execute_process(
COMMAND "@git_EXECUTABLE@" stash save @git_stash_save_options@
WORKING_DIRECTORY "@work_dir@"
COMMAND_ERROR_IS_FATAL ANY
)
endif()
if(git_update_strategy STREQUAL "CHECKOUT")
execute_process(
COMMAND "@git_EXECUTABLE@" checkout "${checkout_name}"
WORKING_DIRECTORY "@work_dir@"
COMMAND_ERROR_IS_FATAL ANY
)
else()
execute_process(
COMMAND "@git_EXECUTABLE@" rebase "${checkout_name}"
WORKING_DIRECTORY "@work_dir@"
RESULT_VARIABLE error_code
OUTPUT_VARIABLE rebase_output
ERROR_VARIABLE rebase_output
)
if(error_code)
# Rebase failed, undo the rebase attempt before continuing
execute_process(
COMMAND "@git_EXECUTABLE@" rebase --abort
WORKING_DIRECTORY "@work_dir@"
)
if(NOT git_update_strategy STREQUAL "REBASE_CHECKOUT")
# Not allowed to do a checkout as a fallback, so cannot proceed
if(need_stash)
execute_process(
COMMAND "@git_EXECUTABLE@" stash pop --index --quiet
WORKING_DIRECTORY "@work_dir@"
)
endif()
message(FATAL_ERROR "\nFailed to rebase in: '@work_dir@'."
"\nOutput from the attempted rebase follows:"
"\n${rebase_output}"
"\n\nYou will have to resolve the conflicts manually")
endif()
# Fall back to checkout. We create an annotated tag so that the user
# can manually inspect the situation and revert if required.
# We can't log the failed rebase output because MSVC sees it and
# intervenes, causing the build to fail even though it completes.
# Write it to a file instead.
string(TIMESTAMP tag_timestamp "%Y%m%dT%H%M%S" UTC)
set(tag_name _cmake_ExternalProject_moved_from_here_${tag_timestamp}Z)
set(error_log_file ${CMAKE_CURRENT_LIST_DIR}/rebase_error_${tag_timestamp}Z.log)
file(WRITE ${error_log_file} "${rebase_output}")
message(WARNING "Rebase failed, output has been saved to ${error_log_file}"
"\nFalling back to checkout, previous commit tagged as ${tag_name}")
execute_process(
COMMAND "@git_EXECUTABLE@" tag -a
-m "ExternalProject attempting to move from here to ${checkout_name}"
${tag_name}
WORKING_DIRECTORY "@work_dir@"
COMMAND_ERROR_IS_FATAL ANY
)
execute_process(
COMMAND "@git_EXECUTABLE@" checkout "${checkout_name}"
WORKING_DIRECTORY "@work_dir@"
COMMAND_ERROR_IS_FATAL ANY
)
endif()
endif()
if(need_stash)
# Put back the stashed changes
execute_process(
COMMAND "@git_EXECUTABLE@" stash pop --index --quiet
WORKING_DIRECTORY "@work_dir@"
RESULT_VARIABLE error_code
)
if(error_code)
# Stash pop --index failed: Try again dropping the index
execute_process(
COMMAND "@git_EXECUTABLE@" reset --hard --quiet
WORKING_DIRECTORY "@work_dir@"
)
execute_process(
COMMAND "@git_EXECUTABLE@" stash pop --quiet
WORKING_DIRECTORY "@work_dir@"
RESULT_VARIABLE error_code
)
if(error_code)
# Stash pop failed: Restore previous state.
execute_process(
COMMAND "@git_EXECUTABLE@" reset --hard --quiet ${head_sha}
WORKING_DIRECTORY "@work_dir@"
)
execute_process(
COMMAND "@git_EXECUTABLE@" stash pop --index --quiet
WORKING_DIRECTORY "@work_dir@"
)
message(FATAL_ERROR "\nFailed to unstash changes in: '@work_dir@'."
"\nYou will have to resolve the conflicts manually")
endif()
endif()
endif()
set(init_submodules "@init_submodules@")
if(init_submodules)
execute_process(
COMMAND "@git_EXECUTABLE@" submodule update @git_submodules_recurse@ --init @git_submodules@
WORKING_DIRECTORY "@work_dir@"
COMMAND_ERROR_IS_FATAL ANY
)
endif()
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