I'm a newbie, sorry if this has been asked before but I couldn't find anything.
Currently, elixir uses last modification dates to determine files that need to be recompiled. ``` $ mix compile # ... $ touch lib/some/file.ex $ mix compile Compiling <n> files (.ex) ``` Could Elixir not verify that in addition to a modification time change, that the actual text content has changed by comparing a hash of it? In the example above, the file `lib/some/file.ex` would be hashed a second time, but no recompilation would occur. Currently, many operations may change the last modification date even if no content at all has changed: * switch to a different branch, switch back * do an interactive rebase: - to rewrite a commit message, - to reorder some commits - to squash some commits together - etc. While the content of the files does not change (at all) in these examples, some very long recompilations may occur because elixir only relies only on modification times and not on file hashes. Hashing a file is orders of magnitude faster than compiling it, and realizing that the potentially large number of compile-time dependencies of a given file do not need to be recompiled is infinitely faster than recompiling them all for nothing. I am presuming that hash collisions are deemed so incredible unlikely to be acceptable, but if not, then I'd ask the same question but with using the complete content of the source file instead of a hash of it. Copying a source file is again an order of magnitude faster than the time it takes to recompile it. -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. To unsubscribe from this group and stop receiving emails from it, send an email to elixir-lang-core+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/e7a68d8d-0102-483d-a4ec-58849eb88ef6n%40googlegroups.com.
