Prepare for future breaking changes in the Digest module
#1151
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Compatibility with a range of compiler (and its standard library) versions can in vast majority of cases be handled by writing code for the oldest supported compiler version. Often times even breaking changes can be handled by changing the code slightly, although in many cases that means that older code will not be compatible with future compiler releases. This patch adds a simple mechanism for compatibility shims in the build system for the rare cases when it is not possible or sufficient to write single code covering all supported compiler (and standard library) versions, including future versions.
The [Digest] module currently provides an implementation of the MD5 algorithm but this is implicit. Sub-modules for explicit algorithm choice were introduced only starting with OCaml 5.2.0. There is a real risk of the [Digest] module default algorithm in future being changed to something other than MD5 (or the implicit default being removed completely). This patch makes the use of MD5 explicit to make the current code compatible with future compiler releases should that change happen. This patch has no effect when compiling with current compilers (or future compilers if the default algorithm is not changed).
[Digest.MD5] was first added in OCaml 5.2.0. Luckily, the sub-module is the same as the main [Digest] module in earlier OCaml releases.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
More details in commit messages. In summary, there is a very real risk of breaking changes to the
Digestmodule coming in future OCaml releases. Better prepare the code for those changes already today.