file: Sort GLOB results to make it deterministic (#14491)

Even though the `file(GLOB)` documentation specifically warns against
using it to collect a list of source files, projects often do it anyway.
Since it uses `readdir()`, the list of files will be unsorted.
This list is often passed directly to add_executable / add_library.
Linking binaries with an unsorted list will make it unreproducible,
which means that the produced binary will differ depending on the
unpredictable `readdir()` order.

To solve those reproducibility issues in a lot of programs (which don't
explicitly `list(SORT)` the list manually), sort the resulting list of
the `file(GLOB)` command.

A more detailed rationale about reproducible builds is available
[here](https://reproducible-builds.org/).
This commit is contained in:
Reiner Herrmann 2016-05-14 12:30:36 +02:00 committed by Brad King
parent d9fd2f5402
commit edcccde7d6
5 changed files with 4 additions and 11 deletions

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@ -103,8 +103,9 @@ Generate a list of files that match the ``<globbing-expressions>`` and
store it into the ``<variable>``. Globbing expressions are similar to store it into the ``<variable>``. Globbing expressions are similar to
regular expressions, but much simpler. If ``RELATIVE`` flag is regular expressions, but much simpler. If ``RELATIVE`` flag is
specified, the results will be returned as relative paths to the given specified, the results will be returned as relative paths to the given
path. No specific order of results is defined. If order is important then path. No specific order of results is defined other than that it is
sort the list explicitly (e.g. using the :command:`list(SORT)` command). deterministic. If order is important then sort the list explicitly
(e.g. using the :command:`list(SORT)` command).
By default ``GLOB`` lists directories - directories are omited in result if By default ``GLOB`` lists directories - directories are omited in result if
``LIST_DIRECTORIES`` is set to false. ``LIST_DIRECTORIES`` is set to false.

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@ -823,6 +823,7 @@ bool cmFileCommand::HandleGlobCommand(std::vector<std::string> const& args,
std::vector<std::string>::size_type cc; std::vector<std::string>::size_type cc;
std::vector<std::string>& files = g.GetFiles(); std::vector<std::string>& files = g.GetFiles();
std::sort(files.begin(), files.end());
for (cc = 0; cc < files.size(); cc++) { for (cc = 0; cc < files.size(); cc++) {
if (!first) { if (!first) {
output += ";"; output += ";";

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@ -12,17 +12,14 @@ file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/dir 2/non_empty_dir/dir 2 subdir fi
file(GLOB CONTENT_LIST "${CMAKE_CURRENT_BINARY_DIR}/test/*/*") file(GLOB CONTENT_LIST "${CMAKE_CURRENT_BINARY_DIR}/test/*/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")
file(GLOB CONTENT_LIST LIST_DIRECTORIES true "${CMAKE_CURRENT_BINARY_DIR}/test/*/*") file(GLOB CONTENT_LIST LIST_DIRECTORIES true "${CMAKE_CURRENT_BINARY_DIR}/test/*/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")
file(GLOB CONTENT_LIST LIST_DIRECTORIES false "${CMAKE_CURRENT_BINARY_DIR}/test/*/*") file(GLOB CONTENT_LIST LIST_DIRECTORIES false "${CMAKE_CURRENT_BINARY_DIR}/test/*/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")

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@ -7,17 +7,14 @@ execute_process(COMMAND ${CMAKE_COMMAND} -E create_symlink "${CMAKE_CURRENT_BINA
file(GLOB_RECURSE CONTENT_LIST FOLLOW_SYMLINKS "${CMAKE_CURRENT_BINARY_DIR}/test/*") file(GLOB_RECURSE CONTENT_LIST FOLLOW_SYMLINKS "${CMAKE_CURRENT_BINARY_DIR}/test/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")
file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES false FOLLOW_SYMLINKS "${CMAKE_CURRENT_BINARY_DIR}/test/*") file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES false FOLLOW_SYMLINKS "${CMAKE_CURRENT_BINARY_DIR}/test/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")
file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES true FOLLOW_SYMLINKS "${CMAKE_CURRENT_BINARY_DIR}/test/*") file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES true FOLLOW_SYMLINKS "${CMAKE_CURRENT_BINARY_DIR}/test/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")

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@ -12,17 +12,14 @@ file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/test/dir 2/non_empty_dir/dir 2 subdir fi
file(GLOB_RECURSE CONTENT_LIST "${CMAKE_CURRENT_BINARY_DIR}/test/*/*") file(GLOB_RECURSE CONTENT_LIST "${CMAKE_CURRENT_BINARY_DIR}/test/*/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")
file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES false "${CMAKE_CURRENT_BINARY_DIR}/test/*/*") file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES false "${CMAKE_CURRENT_BINARY_DIR}/test/*/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")
file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES true "${CMAKE_CURRENT_BINARY_DIR}/test/*/*") file(GLOB_RECURSE CONTENT_LIST LIST_DIRECTORIES true "${CMAKE_CURRENT_BINARY_DIR}/test/*/*")
list(LENGTH CONTENT_LIST CONTENT_COUNT) list(LENGTH CONTENT_LIST CONTENT_COUNT)
message("content: ${CONTENT_COUNT} ") message("content: ${CONTENT_COUNT} ")
list(SORT CONTENT_LIST)
message("${CONTENT_LIST}") message("${CONTENT_LIST}")