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tessl/npm-coc-nvim

tessl install tessl/npm-coc-nvim@0.0.0

LSP based intellisense engine for neovim & vim8.

Call Hierarchy [Intermediate]

Complexity: Intermediate | Category: Navigation

Common Tasks: View callers | View callees | Analyze call graph | Navigate call chains

View and navigate incoming and outgoing calls for functions and methods.

Common Tasks

Show Incoming Calls (Callers)

:call CocAction('showIncomingCalls')

Display functions that call the current function.

Show Outgoing Calls (Callees)

:call CocAction('showOutgoingCalls')

Display functions called by the current function.

Get Call Data

let incoming = CocAction('incomingCalls')
let outgoing = CocAction('outgoingCalls')
echo 'Callers: ' . len(incoming) . ', Callees: ' . len(outgoing)

CocAction API

showIncomingCalls

CocAction('showIncomingCalls')

Show tree view of incoming calls (callers) for the function at cursor.

Example:

nnoremap <silent> <leader>ci :call CocAction('showIncomingCalls')<CR>

" Auto-show incoming calls for entry points
function! ShowCallersIfPublic() abort
  let func = CocAction('getCurrentFunctionSymbol')
  if func =~# '^public'
    call CocAction('showIncomingCalls')
  endif
endfunction

showOutgoingCalls

CocAction('showOutgoingCalls')

Show tree view of outgoing calls (callees) for the function at cursor.

Example:

nnoremap <silent> <leader>co :call CocAction('showOutgoingCalls')<CR>

" Map both
nnoremap <silent> <leader>ci :call CocAction('showIncomingCalls')<CR>
nnoremap <silent> <leader>co :call CocAction('showOutgoingCalls')<CR>

incomingCalls

CocAction('incomingCalls')
" Returns: list

Get incoming calls (callers) data without showing the tree view.

Returns: List of call hierarchy items with properties:

name: Function/method name
kind: Symbol kind
detail: Additional details
location: Location object with uri and range
fromRanges: Array of ranges where calls occur

Example:

let incoming = CocAction('incomingCalls')
echo 'Found ' . len(incoming) . ' callers'

for call in incoming
  echo call.name . ' calls this function'
  if has_key(call, 'location')
    let file = fnamemodify(call.location.uri, ':t')
    echo '  in ' . file
  endif
endfor

outgoingCalls

CocAction('outgoingCalls')
" Returns: list

Get outgoing calls (callees) data without showing the tree view.

Returns: List of call hierarchy items representing functions called by the current function.

Example:

let outgoing = CocAction('outgoingCalls')
echo 'This function calls ' . len(outgoing) . ' functions'

for call in outgoing
  echo '  - ' . call.name
  " Show call locations
  if has_key(call, 'fromRanges')
    for range in call.fromRanges
      let line = range.start.line + 1
      echo '    Line ' . line
    endfor
  endif
endfor

Configuration

Call hierarchy settings in coc-settings.json:

{
  "callHierarchy.enableTooltip": true,
  "callHierarchy.openCommand": "edit"
}

Examples

Basic Call Hierarchy

" Show incoming calls (who calls this function)
nnoremap <silent> <leader>ci :call CocAction('showIncomingCalls')<CR>

" Show outgoing calls (what this function calls)
nnoremap <silent> <leader>co :call CocAction('showOutgoingCalls')<CR>

" Show both in split
nnoremap <silent> <leader>ch :call ShowCallHierarchy()<CR>

function! ShowCallHierarchy() abort
  call CocAction('showIncomingCalls')
  vsplit
  call CocAction('showOutgoingCalls')
endfunction

Display Call Information

function! ShowCallInfo() abort
  let incoming = CocAction('incomingCalls')
  let outgoing = CocAction('outgoingCalls')
  let func = CocAction('getCurrentFunctionSymbol')

  echo "=== Call Hierarchy for: " . func . " ==="
  echo "Incoming calls (callers): " . len(incoming)
  echo "Outgoing calls (callees): " . len(outgoing)

  if len(incoming) > 0
    echo "\nCallers:"
    for call in incoming
      echo "  - " . call.name
      if has_key(call, 'detail')
        echo "    " . call.detail
      endif
    endfor
  endif

  if len(outgoing) > 0
    echo "\nCallees:"
    for call in outgoing
      echo "  - " . call.name
    endfor
  endif
endfunction

command! CallInfo call ShowCallInfo()
nnoremap <silent> <leader>ch :CallInfo<CR>

List All Callers in QuickFix

function! ListAllCallers() abort
  let incoming = CocAction('incomingCalls')

  if len(incoming) == 0
    echo "No callers found"
    return
  endif

  " Build quickfix list
  let qflist = []
  for call in incoming
    if has_key(call, 'location')
      let loc = call.location
      call add(qflist, {
        \ 'filename': substitute(loc.uri, 'file://', '', ''),
        \ 'lnum': loc.range.start.line + 1,
        \ 'col': loc.range.start.character + 1,
        \ 'text': call.name . ' (caller)'
        \ })
    endif
  endfor

  call setqflist(qflist)
  copen
  echo len(incoming) . " callers found"
endfunction

command! ListCallers call ListAllCallers()

Call Graph Statistics

function! CallGraphStats() abort
  let incoming = CocAction('incomingCalls')
  let outgoing = CocAction('outgoingCalls')
  let func = CocAction('getCurrentFunctionSymbol')

  echo "=== Call Graph Statistics for: " . func . " ==="
  echo "Direct callers: " . len(incoming)
  echo "Direct callees: " . len(outgoing)

  " Calculate fan-in and fan-out
  echo "Fan-in (complexity of being called): " . len(incoming)
  echo "Fan-out (complexity of calling others): " . len(outgoing)

  " Determine function type
  if len(incoming) == 0 && len(outgoing) > 0
    echo "Type: Entry point / Root function"
  elseif len(incoming) > 0 && len(outgoing) == 0
    echo "Type: Leaf function"
  elseif len(incoming) > 0 && len(outgoing) > 0
    echo "Type: Intermediate function"
  else
    echo "Type: Isolated function (may be unused)"
  endif
endfunction

command! CallStats call CallGraphStats()

Navigate Call Chain

" Navigate to caller
function! GoToCaller(index) abort
  let incoming = CocAction('incomingCalls')

  if a:index >= len(incoming)
    echo "Caller index out of range"
    return
  endif

  let call = incoming[a:index]
  if has_key(call, 'location')
    let loc = call.location
    let file = substitute(loc.uri, 'file://', '', '')
    let line = loc.range.start.line + 1
    let col = loc.range.start.character + 1

    execute 'edit ' . fnameescape(file)
    call cursor(line, col)
    normal! zz
    echo "Navigated to caller: " . call.name
  endif
endfunction

command! -nargs=1 GoToCaller call GoToCaller(<args>)

" Quick navigation
nnoremap <silent> <leader>c1 :GoToCaller 0<CR>
nnoremap <silent> <leader>c2 :GoToCaller 1<CR>
nnoremap <silent> <leader>c3 :GoToCaller 2<CR>

Show Call Path

function! ShowCallPath() abort
  " Build a simple call path
  let current_func = CocAction('getCurrentFunctionSymbol')

  if empty(current_func)
    echo "Not in a function"
    return
  endif

  let incoming = CocAction('incomingCalls')
  let path = [current_func]

  " Add callers (limited to prevent deep recursion)
  for call in incoming[:2]
    call add(path, call.name)
  endfor

  if len(incoming) > 3
    call add(path, '...')
  endif

  echo "Call path: " . join(reverse(path), ' → ')
endfunction

nnoremap <silent> <leader>cp :call ShowCallPath()<CR>

Interactive Call Tree

function! InteractiveCallTree(direction) abort
  let calls = CocAction(a:direction ==# 'in' ? 'incomingCalls' : 'outgoingCalls')
  let title = a:direction ==# 'in' ? 'Incoming' : 'Outgoing'

  if len(calls) == 0
    echo "No " . tolower(title) . " calls"
    return
  endif

  let items = []
  for i in range(len(calls))
    let text = (i + 1) . '. ' . calls[i].name
    if has_key(calls[i], 'detail')
      let text .= ' - ' . calls[i].detail
    endif
    call add(items, text)
  endfor

  let choice = inputlist(['Select ' . tolower(title) . ' call to navigate:'] + items)

  if choice > 0 && choice <= len(calls)
    let call = calls[choice - 1]
    if has_key(call, 'location')
      let loc = call.location
      let file = substitute(loc.uri, 'file://', '', '')
      execute 'edit ' . fnameescape(file)
      call cursor(loc.range.start.line + 1, loc.range.start.character + 1)
      normal! zz
      echo "Jumped to: " . call.name
    endif
  endif
endfunction

nnoremap <silent> <leader>ci :call InteractiveCallTree('in')<CR>
nnoremap <silent> <leader>co :call InteractiveCallTree('out')<CR>

Export Call Hierarchy

function! ExportCallHierarchy(filename) abort
  let incoming = CocAction('incomingCalls')
  let outgoing = CocAction('outgoingCalls')
  let current = CocAction('getCurrentFunctionSymbol')

  let lines = []
  call add(lines, "Call Hierarchy for: " . current)
  call add(lines, "Generated: " . strftime('%Y-%m-%d %H:%M:%S'))
  call add(lines, "")

  call add(lines, "Incoming Calls (Callers): " . len(incoming))
  for call in incoming
    let line = "  - " . call.name
    if has_key(call, 'location')
      let file = fnamemodify(call.location.uri, ':t')
      let line .= " (" . file . ")"
    endif
    call add(lines, line)
  endfor

  call add(lines, "")
  call add(lines, "Outgoing Calls (Callees): " . len(outgoing))
  for call in outgoing
    call add(lines, "  - " . call.name)
  endfor

  call writefile(lines, a:filename)
  echo "Call hierarchy exported to " . a:filename
endfunction

command! -nargs=1 -complete=file ExportCalls call ExportCallHierarchy(<q-args>)

Find Unused Functions

function! FindUnusedFunctions() abort
  " Find functions with no incoming calls
  let symbols = CocAction('documentSymbols')
  let unused = []

  function! CheckSymbol(symbol) abort closure
    if a:symbol.kind ==# 'Function' || a:symbol.kind ==# 'Method'
      " Would need to position cursor at symbol to check calls
      " This is a simplified example
      let incoming = CocAction('incomingCalls')
      if len(incoming) == 0
        call add(unused, a:symbol.name)
      endif
    endif
  endfunction

  " Note: This is expensive, checking each function individually
  echo "Scanning for unused functions (this may take time)..."

  if len(unused) == 0
    echo "No obviously unused functions found"
  else
    echo "Potentially unused functions:"
    for func in unused
      echo "  - " . func
    endfor
    echo "\nNote: Check if functions are entry points or exported"
  endif
endfunction

command! FindUnused call FindUnusedFunctions()

Call Hierarchy in QuickFix

function! CallHierarchyToQuickFix(direction) abort
  let calls = CocAction(a:direction ==# 'in' ? 'incomingCalls' : 'outgoingCalls')
  let qflist = []

  for call in calls
    if has_key(call, 'location')
      let loc = call.location
      let text = call.name
      if has_key(call, 'detail')
        let text .= ' - ' . call.detail
      endif

      call add(qflist, {
        \ 'filename': substitute(loc.uri, 'file://', '', ''),
        \ 'lnum': loc.range.start.line + 1,
        \ 'col': loc.range.start.character + 1,
        \ 'text': text
        \ })
    endif
  endfor

  if len(qflist) > 0
    call setqflist(qflist)
    copen
    echo len(qflist) . " calls loaded"
  else
    echo "No calls found"
  endif
endfunction

command! IncomingCallsQF call CallHierarchyToQuickFix('in')
command! OutgoingCallsQF call CallHierarchyToQuickFix('out')

nnoremap <silent> <leader>cqi :IncomingCallsQF<CR>
nnoremap <silent> <leader>cqo :OutgoingCallsQF<CR>

Call Count Display

function! ShowCallCounts() abort
  let incoming = CocAction('incomingCalls')
  let outgoing = CocAction('outgoingCalls')
  let func = CocAction('getCurrentFunctionSymbol')

  if empty(func)
    echo "Not in a function"
    return
  endif

  echo func . " is called by " . len(incoming) . " function(s)"
  echo func . " calls " . len(outgoing) . " function(s)"

  " Calculate complexity score
  let complexity = len(outgoing)
  if complexity == 0
    echo "Complexity: Low (leaf function)"
  elseif complexity <= 5
    echo "Complexity: Moderate"
  else
    echo "Complexity: High (consider refactoring)"
  endif
endfunction

nnoremap <silent> <leader>cc :call ShowCallCounts()<CR>

Error Handling

No Call Hierarchy Support

Check if language server supports call hierarchy:

if CocHasProvider('callHierarchy')
  call CocAction('showIncomingCalls')
else
  echo "Language server doesn't support call hierarchy"
endif

Not in Function

Handle cases where cursor isn't in a function:

let func = CocAction('getCurrentFunctionSymbol')
if empty(func)
  echo "Place cursor in a function to view call hierarchy"
else
  call CocAction('showIncomingCalls')
endif

Troubleshooting

Call Hierarchy Not Working

Problem: Call hierarchy commands show nothing.

Solutions:

Check LSP support: echo CocHasProvider('callHierarchy')
Verify cursor is in function: echo CocAction('getCurrentFunctionSymbol')
Check logs: :CocOpenLog
Restart language server: :CocRestart
Update extension: :CocUpdate

Incomplete Call Information

Problem: Some calls are missing.

Solutions:

Language server may not have indexed all files
Save all files and wait for indexing
Check workspace folders: :CocList folders
Restart language server: :CocRestart

Slow Performance

Problem: Call hierarchy is slow to load.

Solutions:

Large codebases may take time to analyze
Disable tooltip: "callHierarchy.enableTooltip": false
Check language server performance in logs
Consider limiting workspace scope

Version

tessl/npm-coc-nvim

call-hierarchy.mddocs/navigation/

Call Hierarchy [Intermediate]

Common Tasks

Show Incoming Calls (Callers)

Show Outgoing Calls (Callees)

Get Call Data

CocAction API

showIncomingCalls

showOutgoingCalls

incomingCalls

outgoingCalls

Configuration

Examples

Basic Call Hierarchy

Display Call Information

List All Callers in QuickFix

Call Graph Statistics

Navigate Call Chain

Show Call Path

Interactive Call Tree

Export Call Hierarchy

Find Unused Functions

Call Hierarchy in QuickFix

Call Count Display

Error Handling

No Call Hierarchy Support

Not in Function

Troubleshooting

Call Hierarchy Not Working

Incomplete Call Information

Slow Performance

See Also

Version

tessl/npm-coc-nvim

call-hierarchy.md.css-3qkkll{font-size:var(--chakra-font-sizes-sm);font-weight:var(--chakra-font-weights-normal);color:var(--chakra-colors-gray-300);}docs/navigation/

Call Hierarchy [Intermediate]

Common Tasks

Show Incoming Calls (Callers)

Show Outgoing Calls (Callees)

Get Call Data

CocAction API

showIncomingCalls

showOutgoingCalls

incomingCalls

outgoingCalls

Configuration

Examples

Basic Call Hierarchy

Display Call Information

List All Callers in QuickFix

Call Graph Statistics

Navigate Call Chain

Show Call Path

Interactive Call Tree

Export Call Hierarchy

Find Unused Functions

Call Hierarchy in QuickFix

Call Count Display

Error Handling

No Call Hierarchy Support

Not in Function

Troubleshooting

Call Hierarchy Not Working

Incomplete Call Information

Slow Performance

See Also

call-hierarchy.mddocs/navigation/