it's useful for e.g. to apply old patches that weren't generated by `got diff' or git-diff(1) and so lacks the metadata needed for the 3-way merge. manpage improvements from and ok stsp@

`got patch -R' fails spectacularly when applied on a diff that contains the info of the original blob for the diff3 merge machinery since it tries to apply the reverse of the patch to the old blob. change it to run the patch (_not_ reversed) on the old blob and then swap the arguments to got_diff3_merge which gives us the correct reverse merge of the diff. while here add a test case too. reported by naddy, discussed with and ok stsp@

This makes 'got patch' try to ignore whitespaces when trying to match a hunk. Discused with and ok stsp@

This fixes a regression introduced with the diff3 merge: files merged this way have their permissions resetted after patch. The issue is due the fact that patch_file looks at a temporary files and not at the original "old file". Reported by and ok stsp@

drop the "simple" part, there's no "complex" way of removing files.

Try to create a file with more than one line, it would have catched an issue with my wip diff for ignore whitespaces in got patch. While here rename the function to drop "simple".

Introduce a patch_start routine that finds the next "diff" header (if there is one); the idea is to persist some state (commit id and wether it's a "git diff") while processing the content of the diff. It's needed because in the case of 'got diff' some information like the commit id are only present once at the beginning. As a consequence, the patch parser becomes slightly more robust (concatenating diffs produced by different means shouldn't confuse it anymore) and drops the support for "old" got diffs, the ones previous the introduction of the "commit -/+" header. ok tracey@

tweak and ok stsp@

Suggested by stsp@. This makes possible to tell if 'got patch' used a merge-base from the repository for the 3-way merge or did a simple search/replace operation. While here update the tests to look for the 'G' status and the manpage, which was also missing the documentation for the 'C' status in got patch. ok stsp@

since diffs are often enclosed in other formats (e.g. emails) we might parse something and think it's a blob id when it's not. This should already happens, but apply_patch is looking for the wrong error due to a leftover from previous attempts. Reported by stsp@ while here tweak the test_patch_merge_unknown_blob to also try with a dummy commit id, as now got-read-patch requires it in order to consider a blob id. ok stsp@

suggested by and ok stsp@

Parse the "blob -" metadata in diffs produced by 'got diff' and use the original file for patching. Then, use the diff3 with the current version of the file to merge the differences. This solves many failures automagically or at least turns them into a conflict. ok/improvements stsp@

Otherwise the test directory it's not left in place; ok tracey@

extend the support for git-style diffs to include the "pure rename" case, i.e. when a file is renamed without any edits. ok stsp@

add a flag to got_patch to reverse a patch before applying and the -R flag for `got patch'. ok stsp@

reminded by and 'looks fine' to stsp@

this allow to apply patches from subdirectories of the work tree root. Prodded by naddy@, ok stsp@.

Move some bits from the libexec helper to the main process so we know if the patch was generated by git or not and finally document the automatic stripping of a/ and b/ prefixes added by git-diff(1). ok stsp@

This fixes a common issue when for e.g. generating patches with $ diff -u foo.orig foo where 'got patch' failed because 'foo.orig' has an 'unexpected status'. prodded by naddy, ok stsp

check_file_status used got_worktree_status to check if the file was in an allowed state, but it's wrong since the callback is not invoked on unchanged files. While here also fix a relate bug: unlink(newpath) is in the wrong spot and ends up removing files even when it shouldn't, so move it early in the got_worktree_schedule_* error handling. Finally, update the appropriate test case. It was passing before because got_worktree_schedule_add returned GOT_ERR_FILE_STATUS, not because check_file_status failed. ok stsp@