# werge (merge weird stuff) This is a partial work-alike of `diff3` and `git merge` and other merge-y tools that is capable of - merging token-size changes instead of line-size ones - largely ignoring changes in blank characters These properties are great for several use-cases: - merging free-flowing text changes (such as in TeX) irrespective of line breaks etc, - merging of change sets that use different code formatters - minimizing the conflict size of tiny changes to a few characters, making them easier to resolve ## Demo Original (`old` file): ``` Roses are red. Violets are blue. Patch is quite hard. I cannot rhyme. ``` Local changes (`my` file): ``` Roses are red. Violets are blue. Patching is hard. I still cannot rhyme. ``` Remote changes (`your` file): ``` Roses are red. Violets are blue. Patch is quite hard. I cannot do verses. ``` Token-merged version with `werge merge my orig your` (conflicts on the space change that is too close to the disappearing "still" token): ``` Roses are red. Violets are blue. Patching is hard.<<<<< I still||||| I===== I>>>>> cannot do verses. ``` (NOTE: option `-G` gives nicely colored output that is much easier to read.) Token-merged version with separate space resolution using `-s` (conflicts get fixed separately): ``` Roses are red. Violets are blue. Patching is hard. I still cannot do verses. ``` A harder-conflicting file (`theirs`): ``` Roses are red. Violets are blue. Merging is quite hard. I cannot do verses. ``` `werge merge mine orig theirs -s` highlights the actual unmergeable change: ``` Roses are red. Violets are blue. <<<<>>>> is hard. I still cannot do verses. ``` ## How does it work? - Instead of lines, the files are torn to small tokens (words, spaces, symbols, ...) and these are diffed and merged individually. - Some tokens are marked as spaces by the tokenizer, which allows the merge algorithm to be (selectively) more zealous when resolving conflicts on these. Compared to e.g. `difftastic`, `mergiraf` and similar tools, **`werge` is completely oblivious about the actual file structure** and works on any file type. This choice trades off some merge quality for (a lot of) complexity. Tokenizers are simple, implementable as linear scanners that print separate tokens on individual lines that are prefixed with a space mark (`.` for space and `|` for non-space), and also escape newlines and backslashes. A default tokenization of string "hello \ world" with a new line at the end is listed below (note the invisible space on the lines with dots): ``` |hello . |\\ . |world .\n ``` Users may supply any tokenizer via option `-F`, e.g. this script makes line-size tokens (reproducing the usual line merges): ``` #!/usr/bin/env python3 import sys for l in sys.stdin.readlines(): if len(l)==0: continue if l[-1]=='\n': print('|'+l[:-1].replace('\\','\\\\')+'\\n') else: print('|'+l.replace('\\','\\\\')) ``` ## Installation ```sh cabal install ``` Running of `werge` requires a working installation of `diff` compatible with the one from [GNU diffutils](https://www.gnu.org/software/diffutils/). You may set up a path to such `diff` (or a wrapper script) via environment variable `WERGE_DIFF`. ## Use with `git` `werge` can automatically process files that are marked in `git` as merge conflicts: ```sh $ git merge somebranch $ werge git -ua ``` Options `-ua` (`--unmerged --add`) find all files that are marked as unmerged, tries to merge them token-by-token, and if the merge is successful with current settings it runs `git add` on them. The current changes in the files are replaced by the merged (or partially merged) state; backups are written automatically to `filename.werge-backup`. ## Current `--help` and features ``` werge -- blanks-friendly mergetool for tiny interdwindled changes Usage: werge [(-F|--tok-filter FILTER) | (-i|--simple-tokens) | (-I|--full-tokens)] [--no-zeal | (-z|--zeal)] [-S|--space (keep|my|old|your)] [-s | --resolve-space (normal|keep|my|old|your)] [--conflict-space-overlaps] [--conflict-space-separate] [--conflict-space-all] [-C|--expand-context N] [--resolve (keep|my|old|your)] [--conflict-overlaps] [--conflict-separate] [--conflict-all] [-G|--color] [--label-start "<<<<<"] [--label-mo "|||||"] [--label-oy "====="] [--label-end ">>>>>"] COMMAND Available options: -F,--tok-filter FILTER External program to separate the text to tokens -i,--simple-tokens Use wider character class to separate the tokens (results in larger tokens and ignores case) -I,--full-tokens Separate characters by all known character classes (default) --no-zeal avoid zealous mode (default) -z,--zeal Try to zealously minify conflicts, potentially resolving them -S,--space (keep|my|old|your) Retain spacing from a selected version, or keep all space changes for merging (default: keep) -s Shortcut for `--resolve-space keep' (this separates space-only conflicts, enabling better automated resolution) --resolve-space (normal|keep|my|old|your) Resolve conflicts in space-only tokens separately, and either keep unresolved conflicts, or resolve in favor of a given version; `normal' resolves the spaces together with other tokens, ignoring choices in --resolve-space-* (default: normal) --conflict-space-overlaps Never resolve overlapping changes in space-only tokens --conflict-space-separate Never resolve separate (non-overlapping) changes in space-only tokens --conflict-space-all Never resolve any changes in space-only tokens -C,--expand-context N Consider changes that are at most N tokens apart to be a single change. Zero may cause bad resolutions of near conflicting edits (default: 1) --resolve (keep|my|old|your) Resolve general conflicts in favor of a given version, or keep the conflicts (default: keep) --conflict-overlaps Never resolve overlapping changes in general tokens --conflict-separate Never resolve separate (non-overlapping) changes in general tokens --conflict-all Never resolve any changes in general tokens -G,--color Use shorter, gaily colored output markers by default (requires ANSI color support; good for terminals or `less -R') --label-start "<<<<<" Label for beginning of the conflict --label-mo "|||||" Separator of local edits and original --label-oy "=====" Separator of original and other people's edits --label-end ">>>>>" Label for end of the conflict -h,--help Show this help text --version Show version information Available commands: merge diff3-style merge of two changesets git Automerge unmerged files in git conflict werge is a free software, use it accordingly. ``` #### Manual merging ``` Usage: werge merge MYFILE OLDFILE YOURFILE diff3-style merge of two changesets Available options: MYFILE Version with local edits OLDFILE Original file version YOURFILE Version with other people's edits -h,--help Show this help text ``` #### Git interoperability ``` Usage: werge git (UNMERGED | (-u|--unmerged)) [(-a|--add) | --no-add] Automerge unmerged files in git conflict Available options: UNMERGED Unmerged file tracked by git (can be specified repeatedly) -u,--unmerged Process all files marked as unmerged by git -a,--add Run `git add' for fully merged files --no-add Prevent running `git add' -h,--help Show this help text ```