Gitsigns blame fails after edit, undo, edit

[AndreasNasman]

Description

The following error happens after editing a file, undoing the change, and then editing it again:

Error executing Lua callback: ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/async.lua:95: The async coroutine failed: ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsig
ns/async.lua:95: The async coroutine failed: ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/blame.lua:104: Invalid 'replacement string' item: expected String, got nil
                                                                                                                                                                         
stack traceback:                                                                                                                                                         
        [C]: in function 'nvim_buf_set_lines'                                                                                                                            
        ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/blame.lua:104: in function 'render'                                                                            
        ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/blame.lua:293: in function <...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/blame.lua:270>                   
stack traceback:                                                                                                                                                         
        [C]: in function 'error'                                                                                                                                         
        ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/async.lua:95: in function 'step'                                                                               
        ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/async.lua:130: in function 'f'                                                                                 
        ...local/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/cli.lua:96: in function <...local/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/cli.lua:61>                     
stack traceback:                                                                                                                                                         
        [C]: in function 'error'                                                                                                                                         
        ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/async.lua:95: in function 'step'                                                                               
        ...cal/share/nvim/lazy/gitsigns.nvim/lua/gitsigns/async.lua:130: in function 'run'                                                                               
        ...se/.local/share/nvim/lazy/gitsigns.nvim/lua/gitsigns.lua:120: in function <...se/.local/share/nvim/lazy/gitsigns.nvim/lua/gitsigns.lua:119>                   

Steps to reproduce:

Neovim version

NVIM v0.11.0-dev-4456+g517ecb85f5-Homebrew Build type: Release LuaJIT 2.1.1732813678 Run "nvim -V1 -v" for more info

Operating system and version

macOS 14.7.1 (23H222)

Expected behavior

:Gitsigns blame should open without an error.

Actual behavior

The error in the description is thrown:

Minimal config

for name, url in pairs{
  gitsigns = 'https://github.com/lewis6991/gitsigns.nvim',
  -- ADD OTHER PLUGINS _NECESSARY_ TO REPRODUCE THE ISSUE
  -- No other plugins.
} do
local install_path = vim.fn.fnamemodify('gitsigns_issue/'..name, ':p')
if vim.fn.isdirectory(install_path) == 0 then
vim.fn.system { 'git', 'clone', '--depth=1', url, install_path }
end
vim.opt.runtimepath:append(install_path)
end

require('gitsigns').setup{
  debug_mode = true, -- You must add this to enable debug messages
  -- ADD GITSIGNS CONFIG THAT IS _NECESSARY_ FOR REPRODUCING THE ISSUE
  -- The default config triggers the error, like `opts = {}` in lazy.nvim.
}

-- ADD INIT.LUA SETTINGS THAT IS _NECESSARY_ FOR REPRODUCING THE ISSUE
-- No settings.

Steps to reproduce

1. mkdir gitsigns_issue
2. cd gitsigns_issue
3. git init
4. echo -e "foo\nbar" > file
5. git add file
6. git commit -m 'initial commit'
7. nvim --clean -u minimal.lua file
8. Keep the cursor on line 1 and add a new line with o.
9. Run :Gitsigns blame and close the blame window.
10. Press u to undo the change.
11. Edit the file again, adding a line with o.
12. Run :Gitsigns blame. This triggers the error.

Screen.Recording.2024-12-13.at.23.32.12.mp4

Gitsigns debug messages

:Gitsigns debug_messages
0.97 D dprintf: Deriving GitSignsAdd from Added
1.04 D derive: Deriving GitSignsChange from Changed
1.07 D derive: Deriving GitSignsDelete from Removed
1.12 D derive: Deriving GitSignsChangedelete from GitSignsChange
1.15 D derive: Deriving GitSignsTopdelete from GitSignsDelete
1.16 D derive: Deriving GitSignsUntracked from GitSignsAdd
1.19 D derive: Deriving GitSignsAddNr from GitSignsAdd
1.21 D derive: Deriving GitSignsChangeNr from GitSignsChange
1.25 D derive: Deriving GitSignsDeleteNr from GitSignsDelete
1.26 D derive: Deriving GitSignsChangedeleteNr from GitSignsChangeNr
1.28 D derive: Deriving GitSignsTopdeleteNr from GitSignsDeleteNr
1.32 D derive: Deriving GitSignsUntrackedNr from GitSignsAddNr
1.35 D derive: Deriving GitSignsAddLn from DiffAdd
1.36 D derive: Deriving GitSignsChangeLn from DiffChange
1.44 D derive: Deriving GitSignsChangedeleteLn from GitSignsChangeLn
1.45 D derive: Deriving GitSignsUntrackedLn from GitSignsAddLn
1.46 D derive: Deriving GitSignsAddCul from GitSignsAdd
1.47 D derive: Deriving GitSignsChangeCul from GitSignsChange
1.49 D derive: Deriving GitSignsDeleteCul from GitSignsDelete
1.50 D derive: Deriving GitSignsChangedeleteCul from GitSignsChangeCul
1.51 D derive: Deriving GitSignsTopdeleteCul from GitSignsDeleteCul
1.54 D derive: Deriving GitSignsUntrackedCul from GitSignsAddCul
1.55 D derive: Deriving GitSignsStagedAdd from GitSignsAdd
1.56 D derive: Deriving GitSignsStagedChange from GitSignsChange
1.58 D derive: Deriving GitSignsStagedDelete from GitSignsDelete
1.60 D derive: Deriving GitSignsStagedChangedelete from GitSignsChangedelete
1.61 D derive: Deriving GitSignsStagedTopdelete from GitSignsTopdelete
1.62 D derive: Deriving GitSignsStagedAddNr from GitSignsAddNr
1.64 D derive: Deriving GitSignsStagedChangeNr from GitSignsChangeNr
1.66 D derive: Deriving GitSignsStagedDeleteNr from GitSignsDeleteNr
1.68 D derive: Deriving GitSignsStagedChangedeleteNr from GitSignsChangedeleteNr
1.69 D derive: Deriving GitSignsStagedTopdeleteNr from GitSignsTopdeleteNr
1.70 D derive: Deriving GitSignsStagedAddLn from GitSignsAddLn
1.73 D derive: Deriving GitSignsStagedChangeLn from GitSignsChangeLn
1.74 D derive: Could not derive GitSignsStagedDeleteLn
1.75 D derive: Deriving GitSignsStagedChangedeleteLn from GitSignsChangedeleteLn
1.76 D derive: Could not derive GitSignsStagedTopdeleteLn
1.77 D derive: Deriving GitSignsStagedAddCul from GitSignsAddCul
1.78 D derive: Deriving GitSignsStagedChangeCul from GitSignsChangeCul
1.79 D derive: Deriving GitSignsStagedDeleteCul from GitSignsDeleteCul
1.80 D derive: Deriving GitSignsStagedChangedeleteCul from GitSignsChangedeleteCul
1.81 D derive: Deriving GitSignsStagedTopdeleteCul from GitSignsTopdeleteCul
1.83 D derive: Deriving GitSignsAddPreview from DiffAdd
1.84 D derive: Deriving GitSignsDeletePreview from DiffDelete
1.55 D derive: Deriving GitSignsStagedAdd from GitSignsAdd                                                                                                               
1.56 D derive: Deriving GitSignsStagedChange from GitSignsChange                                                                                                         
1.58 D derive: Deriving GitSignsStagedDelete from GitSignsDelete                                                                                                         
1.60 D derive: Deriving GitSignsStagedChangedelete from GitSignsChangedelete                                                                                             
1.61 D derive: Deriving GitSignsStagedTopdelete from GitSignsTopdelete                                                                                                   
1.62 D derive: Deriving GitSignsStagedAddNr from GitSignsAddNr                                                                                                           
1.64 D derive: Deriving GitSignsStagedChangeNr from GitSignsChangeNr                                                                                                     
1.66 D derive: Deriving GitSignsStagedDeleteNr from GitSignsDeleteNr                                                                                                     
1.68 D derive: Deriving GitSignsStagedChangedeleteNr from GitSignsChangedeleteNr                                                                                         
1.69 D derive: Deriving GitSignsStagedTopdeleteNr from GitSignsTopdeleteNr                                                                                               
1.70 D derive: Deriving GitSignsStagedAddLn from GitSignsAddLn                                                                                                           
1.73 D derive: Deriving GitSignsStagedChangeLn from GitSignsChangeLn                                                                                                     
1.74 D derive: Could not derive GitSignsStagedDeleteLn                                                                                                                   
1.75 D derive: Deriving GitSignsStagedChangedeleteLn from GitSignsChangedeleteLn                                                                                         
1.76 D derive: Could not derive GitSignsStagedTopdeleteLn                                                                                                                
1.77 D derive: Deriving GitSignsStagedAddCul from GitSignsAddCul                                                                                                         
1.78 D derive: Deriving GitSignsStagedChangeCul from GitSignsChangeCul                                                                                                   
1.79 D derive: Deriving GitSignsStagedDeleteCul from GitSignsDeleteCul                                                                                                   
1.80 D derive: Deriving GitSignsStagedChangedeleteCul from GitSignsChangedeleteCul                                                                                       
1.81 D derive: Deriving GitSignsStagedTopdeleteCul from GitSignsTopdeleteCul                                                                                             
1.83 D derive: Deriving GitSignsAddPreview from DiffAdd                                                                                                                  
1.84 D derive: Deriving GitSignsDeletePreview from DiffDelete                                                                                                            
1.85 D derive: Deriving GitSignsCurrentLineBlame from NonText                                                                                                            
1.86 D derive: Deriving GitSignsAddInline from TermCursor                                                                                                                
1.87 D derive: Deriving GitSignsDeleteInline from TermCursor                                                                                                             
1.88 D derive: Deriving GitSignsChangeInline from TermCursor                                                                                                             
1.90 D derive: Deriving GitSignsAddLnInline from GitSignsAddInline                                                                                                       
1.93 D derive: Deriving GitSignsChangeLnInline from GitSignsChangeInline                                                                                                 
1.94 D derive: Deriving GitSignsDeleteLnInline from GitSignsDeleteInline                                                                                                 
1.97 D derive: Deriving GitSignsDeleteVirtLn from DiffDelete                                                                                                             
1.98 D derive: Deriving GitSignsDeleteVirtLnInLine from GitSignsDeleteLnInline                                                                                           
1.99 D derive: Deriving GitSignsVirtLnum from GitSignsDeleteVirtLn                                                                                                       
14.80 D attach(1): Attaching (trigger=BufReadPost)                                                                                                                       
14.86 D run_job: git --version                                                                                                                                           
20.08 D run_job: git --no-pager --no-optional-locks --literal-pathspecs -c gc.auto=0 rev-parse --show-toplevel --absolute-git-dir --abbrev-ref HEAD                      
24.81 D run_job: git --no-pager --no-optional-locks --literal-pathspecs -c gc.auto=0 --git-dir /Users/nasse/Projects/gitsigns_issue/.git config user.name                
28.83 D run_job: git --no-pager --no-optional-locks --literal-pathspecs -c gc.auto=0 --git-dir /Users/nasse/Projects/gitsigns_issue/.git -c core.quotepath=off ls-files -
-stage --others --exclude-standard --eol /Users/nasse/Projects/gitsigns_issue/file                                                                                       
33.84 D watch_gitdir(1): Watching git dir                                                                                                                                
34.06 D run_job: git --no-pager --no-optional-locks --literal-pathspecs -c gc.auto=0 --git-dir /Users/nasse/Projects/gitsigns_issue/.git show 3bd1f0e29744a1f32b08d5650e6
2e2e62afb177c                                                                                                                                                            
38.76 D run_job: git --no-pager --no-optional-locks --literal-pathspecs -c gc.auto=0 --git-dir /Users/nasse/Projects/gitsigns_issue/.git show HEAD:file                  
5479.10 D cli.run: Running action 'blame' with arguments {}                                                                                                              
5480.38 D run_job: git --no-pager --no-optional-locks --literal-pathspecs -c gc.auto=0 --git-dir /Users/nasse/Projects/gitsigns_issue/.git blame --contents - --increment
al -- /Users/nasse/Projects/gitsigns_issue/file                                                                                                                          
9618.14 D cli.run: Running action 'blame' with arguments {}                                                                                                              
14200.82 D cli.run: Running action 'debug_messages' with arguments {}                                                                                                    
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Gitsigns cache

:Gitsigns dump_cache                                                                                                                                                     
{ {                                                                                                                                                                      
    blame = { "...",                                                                                                                                                     
      length = 2                                                                                                                                                         
    },                                                                                                                                                                   
    bufnr = 1,                                                                                                                                                           
    compare_text = { "...",                                                                                                                                              
      head = "foo",                                                                                                                                                      
      length = 3                                                                                                                                                         
    },                                                                                                                                                                   
    compare_text_head = { "...",                                                                                                                                         
      head = "foo",                                                                                                                                                      
      length = 3                                                                                                                                                         
    },                                                                                                                                                                   
    file = "/Users/nasse/Projects/gitsigns_issue/file",                                                                                                                  
    force_next_update = false,                                                                                                                                           
    git_obj = {                                                                                                                                                          
      encoding = "utf-8",                                                                                                                                                
      file = "/Users/nasse/Projects/gitsigns_issue/file",                                                                                                                
      i_crlf = false,                                                                                                                                                    
      mode_bits = "100644",                                                                                                                                              
      object_name = "3bd1f0e29744a1f32b08d5650e62e2e62afb177c",                                                                                                          
      relpath = "file",                                                                                                                                                  
      repo = {                                                                                                                                                           
        abbrev_head = "main",                                                                                                                                            
        detached = false,                                                                                                                                                
        gitdir = "/Users/nasse/Projects/gitsigns_issue/.git",                                                                                                            
        toplevel = "/Users/nasse/Projects/gitsigns_issue",                                                                                                               
        username = "Andreas Näsman"                                                                                                                                      
      },                                                                                                                                                                 
      w_crlf = false                                                                                                                                                     
    },                                                                                                                                                                   
    gitdir_watcher = <userdata 1>,                                                                                                                                       
    hunks = { "...",                                                                                                                                                     
      head = {                                                                                                                                                           
        added = {                                                                                                                                                        
          count = 1,                                                                                                                                                     
          lines = { "" },                                                                                                                                                
          start = 2                                                                                                                                                      
        },                                                                                                                                                               
        head = "@@ -1 +2,1 @@",                                                                                                                                          
        removed = {                                                                                                                                                      
          count = 0,                                                                                                                                                     
          lines = {},                                                                                                                                                    
          start = 1                                                                                                                                                      
        },                                                                                                                                                               
        type = "add",                                                                                                                                                    
        vend = 2                                                                                                                                                         
      },                                                                                                                                                                 
      length = 1                                                                                                                                                         
    },                                                                                                                                                                   
    hunks_staged = { "...",                                                                                                                                              
      length = 0                                                                                                                                                         
    },                                                                                                                                                                   
    staged_diffs = { "...",                                                                                                                                              
      length = 0                                                                                                                                                         
    }                                                                                                                                                                    
  } }                                                                                                                                                                    
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[AndreasNasman]

Related to #1121 I think.