Resolve merge conflicts in a three-pane merge window

.github/workflows/main.yml

@@ -151,11 +151,15 @@ jobs:
       - name: Check out repository code
         uses: actions/checkout@v4
 
+      # The neovim PPA has no build for every Ubuntu ubuntu-latest moves to:
+      # use the pinned release like the Test job
       - name: Install vim and neovim
         run: |
-          sudo add-apt-repository ppa:neovim-ppa/stable -y
           sudo apt-get update
-          sudo apt-get -y install vim neovim
+          sudo apt-get -y install vim
+          curl -fsSL https://github.com/neovim/neovim/releases/download/v0.11.6/nvim-linux-x86_64.tar.gz \
+            | sudo tar -xz -C /opt
+          echo /opt/nvim-linux-x86_64/bin >> "$GITHUB_PATH"
 
       - name: Clone vim-test
         run: |

README.md

@@ -197,6 +197,9 @@ let g:vim_project_local_config = {
 | <kbd>s</kbd> | shelve: save the changes as a patch and revert them |
 | <kbd>S</kbd> | unshelve a shelf or one of its files |
 | <kbd>u</kbd> / <kbd>p</kbd> / <kbd>P</kbd> | pull, push, pull then push, in the background |
+| <kbd>A</kbd> | abort the merge, rebase, cherry-pick or revert in progress |
+
+Merge conflicts: a pull or branch merge that stops on conflicts opens the Unmerged changelist. <kbd>Enter</kbd> on a file opens a three-pane merge window, yours | result | theirs, with each conflict colored by state. Press <kbd>&lt;</kbd> yours, <kbd>&gt;</kbd> theirs, <kbd>=</kbd> both, <kbd>e</kbd> edit, <kbd>u</kbd> undo, <kbd>]c</kbd> / <kbd>[c</kbd> move, <kbd>q</kbd> to accept (write and `git add`) once all are resolved, <kbd>Q</kbd> to discard. After the last file it offers to commit the merge or continue the rebase.
 
 ### Git log, file history, branches and tags
 
@@ -209,7 +212,7 @@ let g:vim_project_local_config = {
 
 - `:ProjectGitLog` searches commits by message, author or hash, with the changed files of the selected one beside it.
 - `:ProjectGitFileHistory` shows the commits of the current file, or of the selected lines, with their diffs.
-- `:ProjectGitBranch` switches, creates and merges branches.
+- `:ProjectGitBranch` switches, creates and merges branches. It fetches remotes in the background and refreshes the list when done.
 - `:ProjectGitTag` checks out and creates tags.
 
 | List | Key | Action |

autoload/project/config.vim

@@ -38,6 +38,7 @@ let s:default = {
       \'new_project_base':              '',
       \'new_tasks_post_cmd':            '',
       \'commit_message':                '',
+      \'git_branch_fetch':              1,
       \'find_replace_separator':        ' => ',
       \'debug':                         0,
       \}
@@ -105,6 +106,20 @@ let s:default.git_local_changes_mappings = {
       \'force_push': '<NOP>',
       \'shelf': 's',
       \'unshelf': 'S',
+      \'abort_merge': 'A',
+      \}
+let s:default.git_merge_mappings = {
+      \'take_yours': '<',
+      \'take_theirs': '>',
+      \'take_both': '=',
+      \'undo': 'u',
+      \'edit': 'e',
+      \'next': ']c',
+      \'previous': '[c',
+      \'all_yours': 'L',
+      \'all_theirs': 'R',
+      \'finish': 'q',
+      \'quit': 'Q',
       \}
 let s:default.file_open_types = {
       \'':  'edit',
@@ -126,6 +141,7 @@ let s:merge_keys = [
       \'git_diff_mappings',
       \'git_changes_mappings',
       \'git_local_changes_mappings',
+      \'git_merge_mappings',
       \]
 
 " Options a project's init.vim may set. Lists and dicts extend the global

autoload/project/git.vim

@@ -42,6 +42,8 @@ let s:changed_files = []
 let s:untracked_files = []
 let s:staged_files = []
 let s:unmerged_files = []
+" Statuses of git status --porcelain for unmerged paths
+let s:unmerged_status = ['DD', 'AU', 'UD', 'UA', 'DU', 'AA', 'UU']
 let s:commit_files = []
 let s:file_regexp = '|\zs.*\ze|'
 let s:directory_regexp = '| \zs.*$'
@@ -899,6 +901,11 @@ function! s:OpenFolderOrFile()
       return
     endif
 
+    if index(s:unmerged_files, 'U '.file) != -1
+      call project#git_merge#Open(file)
+      return
+    endif
+
     let diff_file = s:TryGetDiffFile(file)
     wincmd k
     if empty(diff_file)
@@ -1647,7 +1654,12 @@ function! s:ParseGitStatus()
     let status = strpart(line, 0, 2)
     let filepath = strpart(line, 3)
 
-    if status[0] != ' ' && status[0] != '?' && status[0] != 'U' " Staged files
+    if index(s:unmerged_status, status) != -1 " Merge conflicts
+      call add(s:unmerged_files, 'U '.filepath)
+      continue
+    endif
+
+    if status[0] != ' ' && status[0] != '?' " Staged files
       call add(s:staged_files, status[0].' '.filepath)
     endif
 
@@ -1658,10 +1670,6 @@ function! s:ParseGitStatus()
     if status == '??' " Untracked files
       call add(s:untracked_files, '? '.filepath)
     endif
-
-    if status == 'UU' " Merge conflicts
-      call add(s:unmerged_files, 'U '.filepath)
-    endif
   endfor
 endfunction
 
@@ -1795,6 +1803,7 @@ function! s:SetupChangelistBuffer()
   call s:AddVisualMapping(mappings.shelf, '<SID>ShelfFile()')
   call s:AddMapping(mappings.unshelf, '<SID>UnshelfFile()')
   call s:AddVisualMapping(mappings.unshelf, '<SID>UnshelfFile()')
+  call s:AddMapping(mappings.abort_merge, 'project#git_merge#Abort()')
 
   hi default DiffBufferModify ctermfg=3 guifg=#b58900
   hi default DiffBufferAdd ctermfg=2 guifg=#719e07
@@ -2093,7 +2102,9 @@ function! s:OnGitJobDone(cmd, done_message, OnSuccess, ctx, status)
   let s:git_job = v:null
   let lines = filter(copy(a:ctx.lines), '!empty(v:val)')
   if a:status != 0
-    call project#WarnCommandOutput(a:cmd, lines)
+    if !project#git_merge#ShowConflicts()
+      call project#WarnCommandOutput(a:cmd, lines)
+    endif
     return
   endif
 

autoload/project/git_branch.vim

@@ -25,6 +25,13 @@ function! s:Highlight(state)
 endfunction
 
 function! s:Init(input)
+  let s:refs = s:GetRefs()
+  let s:list = s:LoadBranches()
+  call s:Update(a:input)
+  call s:StartFetch()
+endfunction
+
+function! s:LoadBranches()
   let format = join(['%(HEAD)', '%(refname:short)', '%(upstream:short)',
         \'%(contents:subject)', '%(authorname)',  '%(committerdate:relative)'], s:splitter)
   let cmd = 'git branch -a --format='.shellescape(format)
@@ -36,8 +43,87 @@ function! s:Init(input)
   endif
   call insert(branches, s:CreateItem(' ', s:item_splitter))
   call insert(branches, s:CreateItem('+', s:item_new_branch))
-  let s:list = s:GetTabulatedList(branches)
-  call s:Update(a:input)
+  return s:GetTabulatedList(branches)
+endfunction
+
+" ---------------------------------------------------------------- fetch
+
+" Remote branches are only as new as the last fetch: fetch in the background
+" each time the list opens, then show them again if it is still open. git
+" cannot ask for credentials without a terminal, so it fails instead
+let s:fetch_job = v:null
+let s:refs = []
+
+function! s:StartFetch()
+  if !project#config#Get('git_branch_fetch') || s:fetch_job isnot v:null
+        \|| !(exists('*job_start') || exists('*jobstart'))
+        \|| empty(project#RunShellCmd('git remote', 0))
+    return
+  endif
+
+  let ctx = {'lines': []}
+  let cmd = [&shell, &shellcmdflag, 'git fetch --all --prune --quiet']
+  let env = {'GIT_TERMINAL_PROMPT': '0'}
+  if exists('*job_start')
+    let s:fetch_job = job_start(cmd, {
+          \'cwd': $vim_project,
+          \'env': env,
+          \'in_io': 'null',
+          \'out_cb': {_, line -> add(ctx.lines, line)},
+          \'err_cb': {_, line -> add(ctx.lines, line)},
+          \'exit_cb': function('s:OnVimFetchExit', [ctx]),
+          \})
+  else
+    let s:fetch_job = jobstart(cmd, {
+          \'cwd': $vim_project,
+          \'env': env,
+          \'stdin': 'null',
+          \'stdout_buffered': v:true,
+          \'stderr_buffered': v:true,
+          \'on_stdout': {_, data, __ -> extend(ctx.lines, data)},
+          \'on_stderr': {_, data, __ -> extend(ctx.lines, data)},
+          \'on_exit': {_, status, __ -> s:OnFetched(status, ctx)},
+          \})
+  endif
+endfunction
+
+" exit_cb may run before the output was read
+function! s:OnVimFetchExit(ctx, job, status)
+  call timer_start(10, {-> s:OnFetched(a:status, a:ctx)})
+endfunction
+
+function! s:OnFetched(status, ctx)
+  let s:fetch_job = v:null
+  if !project#list#IsOpen('GIT_BRANCH')
+    return
+  endif
+  if a:status != 0
+    let lines = filter(copy(a:ctx.lines), '!empty(v:val)')
+    call project#list#SetInfoOnClose('git fetch failed: '.get(lines, 0, 'exit '.a:status))
+    return
+  endif
+
+  " Redraw only when a branch moved, not to flash the list for nothing
+  let refs = s:GetRefs()
+  if refs == s:refs
+    return
+  endif
+  let list = s:LoadBranches()
+  " Two items are New Branch and the splitter: keep the list on an error
+  if len(list) <= 2
+    return
+  endif
+  let s:refs = refs
+  let s:list = list
+  call s:Update(project#list#State().user_input)
+  call project#list#RedrawInputLine()
+endfunction
+
+" Branches and the commits they point to, to tell whether a fetch changed any
+function! s:GetRefs()
+  let format = shellescape('%(refname) %(objectname) %(upstream)')
+  let cmd = 'git for-each-ref --format='.format.' refs/heads refs/remotes'
+  return project#RunShellCmd(cmd, 0)
 endfunction
 
 function! s:Update(input)
@@ -111,8 +197,11 @@ function! s:MergeBranch(state)
 
   let cmd = 'git merge '.shellescape(name)
 
-  call project#RunShellCmd(cmd)
+  let output = project#RunShellCmd(cmd, 0)
   if v:shell_error
+    " Once the list is closed
+    call timer_start(0, {-> project#git_merge#ShowConflicts()
+          \|| project#WarnCommandOutput(cmd, output)})
     return 'close'
   endif
   let a:state.offset = 0