fix(version): handle version checks more gracefully

- Avoid emitting errors when the version check fails.
- Put version checking into separate module.
- Pull in upstream changes for vim.system.

Fixes: #948
Closes: #960

lua/gitsigns.lua

@@ -180,7 +180,7 @@ M.setup = async.void(function(cfg)
 
   if config._test_mode then
     require('gitsigns.attach')._setup()
-    require('gitsigns.git')._set_version(config._git_version)
+    require('gitsigns.git.version').check()
   end
 
   if config.auto_attach then

lua/gitsigns/async.lua

@@ -147,7 +147,8 @@ end
 --- @param argc number: The number of arguments of func. Must be included.
 --- @return function: Returns an async function
 function M.wrap(func, argc)
-  assert(argc)
+  assert(type(func) == 'function')
+  assert(type(argc) == 'number')
   return function(...)
     if not M.running() then
       return func(...)

lua/gitsigns/debug/log.lua

@@ -114,7 +114,7 @@ local function eprint(msg, level)
   if info then
     msg = string.format('(ERROR) %s(%d): %s', info.short_src, info.currentline, msg)
   end
-  M.messages[#M.messages + 1] = msg
+  M.messages[#M.messages + 1] = debug.traceback(msg)
   if M.debug_mode then
     error(msg, 3)
   end
@@ -128,4 +128,12 @@ function M.eprintf(fmt, ...)
   eprint(fmt:format(...), 1)
 end
 
+function M.assert(cond, msg)
+  if not cond then
+    eprint(msg, 1)
+  end
+
+  return not cond
+end
+
 return M

lua/gitsigns/git.lua

@@ -8,18 +8,17 @@ local system = require('gitsigns.system').system
 local gs_config = require('gitsigns.config')
 local config = gs_config.config
 
-local uv = vim.loop
-local startswith = vim.startswith
+local uv = vim.uv or vim.loop
 
-local dprint = require('gitsigns.debug.log').dprint
-local dprintf = require('gitsigns.debug.log').dprintf
-local eprint = require('gitsigns.debug.log').eprint
-local err = require('gitsigns.message').error
+local dprint = log.dprint
+local dprintf = log.dprintf
 local error_once = require('gitsigns.message').error_once
 
+local check_version = require('gitsigns.git.version').check
+
 local M = {}
 
---- @type fun(cmd: string[], opts?: SystemOpts): vim.SystemCompleted
+--- @type fun(cmd: string[], opts?: vim.SystemOpts): vim.SystemCompleted
 local asystem = async.wrap(system, 3)
 
 --- @param file string
@@ -59,84 +58,14 @@ M.Obj = Obj
 local Repo = {}
 M.Repo = Repo
 
---- @class (exact) Gitsigns.Version
---- @field major integer
---- @field minor integer
---- @field patch integer
-
---- @param version string
---- @return Gitsigns.Version
-local function parse_version(version)
-  assert(version:match('%d+%.%d+%.%w+'), 'Invalid git version: ' .. version)
-  local ret = {}
-  local parts = vim.split(version, '%.')
-  ret.major = assert(tonumber(parts[1]))
-  ret.minor = assert(tonumber(parts[2]))
-
-  if parts[3] == 'GIT' then
-    ret.patch = 0
-  else
-    local patch_ver = vim.split(parts[3], '-')
-    ret.patch = assert(tonumber(patch_ver[1]))
-  end
-
-  return ret
-end
-
---- Usage: check_version{2,3}
---- @param version {[1]: integer, [2]:integer, [3]:integer}
---- @return boolean
-local function check_version(version)
-  if not M.version then
-    return false
-  end
-  if M.version.major < version[1] then
-    return false
-  end
-  if version[2] and M.version.minor < version[2] then
-    return false
-  end
-  if version[3] and M.version.patch < version[3] then
-    return false
-  end
-  return true
-end
-
---- @async
---- @param version string
-function M._set_version(version)
-  if version ~= 'auto' then
-    M.version = parse_version(version)
-    return
-  end
-
-  --- @type vim.SystemCompleted
-  local obj = asystem({ 'git', '--version' })
-
-  local line = vim.split(obj.stdout or '', '\n', { plain = true })[1]
-  if not line then
-    err("Unable to detect git version as 'git --version' failed to return anything")
-    eprint(obj.stderr)
-    return
-  end
-  assert(type(line) == 'string', 'Unexpected output: ' .. line)
-  assert(startswith(line, 'git version'), 'Unexpected output: ' .. line)
-  local parts = vim.split(line, '%s+')
-  M.version = parse_version(parts[3])
-end
-
---- @class Gitsigns.Git.JobSpec : SystemOpts
+--- @class Gitsigns.Git.JobSpec : vim.SystemOpts
 --- @field command? string
 --- @field ignore_error? boolean
 
 --- @param args string[]
 --- @param spec? Gitsigns.Git.JobSpec
 --- @return string[] stdout, string? stderr
 local git_command = async.create(function(args, spec)
-  if not M.version then
-    M._set_version(config._git_version)
-  end
-
   spec = spec or {}
 
   local cmd = {
@@ -275,8 +204,7 @@ function M.get_repo_info(path, cmd, gitdir, toplevel)
   local has_abs_gd = check_version({ 2, 13 })
   local git_dir_opt = has_abs_gd and '--absolute-git-dir' or '--git-dir'
 
-  -- Wait for internal scheduler to settle before running command
-  --    https://github.com/lewis6991/gitsigns.nvim/pull/215
+  -- Wait for internal scheduler to settle before running command (#215)
   scheduler()
 
   local args = {}

lua/gitsigns/git/version.lua

@@ -0,0 +1,101 @@
+local async = require('gitsigns.async')
+local gs_config = require('gitsigns.config')
+
+local log = require('gitsigns.debug.log')
+local err = require('gitsigns.message').error
+local system = require('gitsigns.system').system
+
+local M = {}
+
+--- @type fun(cmd: string[], opts?: vim.SystemOpts): vim.SystemCompleted
+local asystem = async.wrap(system, 3)
+
+--- @class (exact) Gitsigns.Version
+--- @field major integer
+--- @field minor integer
+--- @field patch integer
+
+--- @param version string
+--- @return Gitsigns.Version
+local function parse_version(version)
+  assert(version:match('%d+%.%d+%.%w+'), 'Invalid git version: ' .. version)
+  local ret = {}
+  local parts = vim.split(version, '%.')
+  ret.major = assert(tonumber(parts[1]))
+  ret.minor = assert(tonumber(parts[2]))
+
+  if parts[3] == 'GIT' then
+    ret.patch = 0
+  else
+    local patch_ver = vim.split(parts[3], '-')
+    ret.patch = assert(tonumber(patch_ver[1]))
+  end
+
+  return ret
+end
+
+local function set_version()
+  local version = gs_config.config._git_version
+  if version ~= 'auto' then
+    local ok, ret = pcall(parse_version, version)
+    if ok then
+      M.version = ret
+    else
+      err(ret --[[@as string]])
+    end
+    return
+  end
+
+  --- @type vim.SystemCompleted
+  local obj = asystem({ 'git', '--version' })
+  async.scheduler()
+
+  local line = vim.split(obj.stdout or '', '\n')[1]
+  if not line then
+    err("Unable to detect git version as 'git --version' failed to return anything")
+    log.eprint(obj.stderr)
+    return
+  end
+
+  -- Sometime 'git --version' returns an empty string (#948)
+  if log.assert(type(line) == 'string', 'Unexpected output: ' .. line) then
+    return
+  end
+
+  if log.assert(vim.startswith(line, 'git version'), 'Unexpected output: ' .. line) then
+    return
+  end
+
+  local parts = vim.split(line, '%s+')
+  M.version = parse_version(parts[3])
+end
+
+--- Usage: check_version{2,3}
+--- @param version {[1]: integer, [2]:integer, [3]:integer}?
+--- @return boolean
+function M.check(version)
+  if not M.version then
+    set_version()
+  end
+
+  if not M.version then
+    return false
+  end
+
+  if not version then
+    return false
+  end
+
+  if M.version.major < version[1] then
+    return false
+  end
+  if version[2] and M.version.minor < version[2] then
+    return false
+  end
+  if version[3] and M.version.patch < version[3] then
+    return false
+  end
+  return true
+end
+
+return M

lua/gitsigns/system/compat.lua

@@ -25,7 +25,7 @@ local function close_handles(state)
   close_handle(state.timer)
 end
 
---- @class Pckr.SystemObj : vim.SystemObj
+--- @class Gitsigns.SystemObj : vim.SystemObj
 --- @field private _state vim.SystemState
 local SystemObj = {}
 
@@ -59,14 +59,14 @@ function SystemObj:wait(timeout)
 
   local done = vim.wait(timeout or state.timeout or MAX_TIMEOUT, function()
     return state.result ~= nil
-  end)
+  end, nil, true)
 
   if not done then
     -- Send sigkill since this cannot be caught
     self:_timeout(SIG.KILL)
     vim.wait(timeout or state.timeout or MAX_TIMEOUT, function()
       return state.result ~= nil
-    end)
+    end, nil, true)
   end
 
   return state.result
@@ -140,9 +140,13 @@ local function setup_input(input)
   return assert(uv.new_pipe(false)), towrite
 end
 
-local environ = vim.fn.environ()
-environ['NVIM'] = vim.v.servername
-environ['NVIM_LISTEN_ADDRESS'] = nil
+--- @return table<string,string>
+local function base_env()
+  local env = vim.fn.environ() --- @type table<string,string>
+  env['NVIM'] = vim.v.servername
+  env['NVIM_LISTEN_ADDRESS'] = nil
+  return env
+end
 
 --- uv.spawn will completely overwrite the environment
 --- when we just want to modify the existing one, so
@@ -156,7 +160,7 @@ local function setup_env(env, clear_env)
   end
 
   --- @type table<string,string|number>
-  env = vim.tbl_extend('force', environ, env or {})
+  env = vim.tbl_extend('force', base_env(), env or {})
 
   local renv = {} --- @type string[]
   for k, v in pairs(env) do
@@ -261,7 +265,7 @@ end
 --- Run a system command
 ---
 --- @param cmd string[]
---- @param opts? SystemOpts
+--- @param opts? vim.SystemOpts
 --- @param on_exit? fun(out: vim.SystemCompleted)
 --- @return vim.SystemObj
 local function system(cmd, opts, on_exit)