Hi Johannes, On Tue, Dec 06, 2022 at 03:07:47PM +0000, Johannes Schindelin via GitGitGadget wrote: > Learning the lesson to avoid shell scripting wherever possible, the Git > for Windows project implemented a minimal replacement for > `mingw_test_cmp` in the form of a `test-tool` subcommand that parses the > input files line by line, ignoring line endings, and compares them. > Essentially the same thing as `mingw_test_cmp`, but implemented in > C instead of Bash. This solution served the Git for Windows project > well, over years. > > However, when this solution was finally upstreamed, the conclusion was > reached that a change to use `git diff --no-index` instead of > `mingw_test_cmp` was more easily reviewed and hence should be used > instead. > > The reason why this approach was not even considered in Git for Windows > is that in 2007, there was already a motion on the table to use Git's > own diff machinery to perform comparisons in Git's test suite, but it > was dismissed in https://lore.kernel.org/git/xmqqbkrpo9or.fsf@gitster.g/ > as undesirable because tests might potentially succeed due to bugs in > the diff machinery when they should not succeed, and those bugs could > therefore hide regressions that the tests try to prevent. > > By the time Git for Windows' `mingw-test-cmp` in C was finally > contributed to the Git mailing list, reviewers agreed that the diff > machinery had matured enough and should be used instead. > > When the concern was raised that the diff machinery, due to its > complexity, would perform substantially worse than the test helper > originally implemented in the Git for Windows project, a test > demonstrated that these performance differences are well lost within the > 100+ minutes it takes to run Git's test suite on Windows. Thanks for this update. I think these five paragraphs are an accurate and helpful record of the history behind this patch and approach. It is very much appreciated. Thanks, Taylor
