1 files changed, 183 insertions, 0 deletions
diff --git a/scripts/lintcommit.lua b/scripts/lintcommit.lua
new file mode 100644
index 0000000000..4aee47b10d
--- /dev/null
+++ b/scripts/lintcommit.lua
@@ -0,0 +1,183 @@
+-- Usage:
+--    nvim -es +'luafile scripts/lintcommit.lua'
+
+local trace = true
+
+-- Print message
+local function p(s)
+  vim.cmd('set verbose=1')
+  vim.api.nvim_echo({{s, ''}}, false, {})
+  vim.cmd('set verbose=0')
+end
+
+local function die()
+  p('')
+  vim.cmd("cquit 1")
+end
+
+-- Executes and returns the output of `cmd`, or nil on failure.
+--
+-- Prints `cmd` if `trace` is enabled.
+local function run(cmd, or_die)
+  if trace then
+    p('run: '..vim.inspect(cmd))
+  end
+  local rv = vim.trim(vim.fn.system(cmd)) or ''
+  if vim.v.shell_error ~= 0 then
+    if or_die then
+      p(rv)
+      die()
+    end
+    return nil
+  end
+  return rv
+end
+
+local function commit_message_is_ok(commit_message)
+  local commit_split = vim.split(commit_message, ":")
+
+  -- Return true if the type is vim-patch since most of the normal rules don't
+  -- apply.
+  if commit_split[1] == "vim-patch" then
+    return true
+  end
+
+  -- Check that message isn't too long.
+  if commit_message:len() > 80 then
+    p([[Commit message is too long, a maximum of 80 characters is allowed.]])
+    return false
+  end
+
+  -- Return false if no colons are detected.
+  if vim.tbl_count(commit_split) < 2 then
+    p([[Commit message does not include colons.]])
+    return false
+  end
+
+  local before_colon = commit_split[1]
+  local after_colon = commit_split[2]
+
+  -- Check if commit introduces a breaking change.
+  if vim.endswith(before_colon, "!") then
+    before_colon = before_colon:sub(1, -2)
+  end
+
+  -- Check if type is correct
+  local type = vim.split(before_colon, "%(")[1]
+  local allowed_types = {"build", "ci", "docs", "feat", "fix", "perf", "refactor", "revert", "test", "chore"}
+  if not vim.tbl_contains(allowed_types, type) then
+    p([[Commit type is not recognized. Allowed types are: build, ci, docs, feat, fix, perf, refactor, revert, test, chore.]])
+    return false
+  end
+
+  -- Check if scope is empty
+  if before_colon:match("%(") then
+    local scope = vim.trim(before_colon:match("%((.*)%)"))
+    if scope == '' then
+      p([[Scope can't be empty.]])
+      return false
+    end
+  end
+
+  -- Check that description doesn't end with a period
+  if vim.endswith(after_colon, ".") then
+      p([[Description ends with a period (\".\").]])
+    return false
+  end
+
+  -- Check that description has exactly one whitespace after colon, followed by
+  -- a lowercase letter and then any number of letters.
+  if not string.match(after_colon, '^ %l%a*') then
+      p([[There should be one whitespace after the colon and the first letter should lowercase.]])
+    return false
+  end
+
+  return true
+end
+
+local function main()
+  local branch = run({'git', 'branch', '--show-current'}, true)
+  local ancestor = run({'git', 'merge-base', 'origin/master', branch})
+  if not ancestor then
+    ancestor = run({'git', 'merge-base', 'upstream/master', branch})
+  end
+  local commits_str = run({'git', 'rev-list', ancestor..'..'..branch}, true)
+
+  local commits = {}
+  for substring in commits_str:gmatch("%S+") do
+     table.insert(commits, substring)
+  end
+
+  for _, commit_hash in ipairs(commits) do
+    local message = run({'git', 'show', '-s', '--format=%s' , commit_hash})
+    if vim.v.shell_error ~= 0 then
+      p('Invalid commit-id: '..commit_hash..'"')
+    elseif not commit_message_is_ok(message) then
+      p('Invalid commit format: '..message)
+      die()
+    end
+  end
+end
+
+local function _test()
+  local good_messages = {
+    "ci: normal message",
+    "build: normal message",
+    "docs: normal message",
+    "feat: normal message",
+    "fix: normal message",
+    "perf: normal message",
+    "refactor: normal message",
+    "revert: normal message",
+    "test: normal message",
+    "chore: normal message",
+    "ci(window): message with scope",
+    "ci!: message with breaking change",
+    "ci(tui)!: message with scope and breaking change",
+    "vim-patch:8.2.3374: Pyret files are not recognized (#15642)",
+    "vim-patch:8.1.1195,8.2.{3417,3419}",
+  }
+
+  local bad_messages = {
+    ":no type before colon 1",
+    " :no type before colon 2",
+    "  :no type before colon 3",
+    "ci(empty description):",
+    "ci(whitespace as description): ",
+    "docs(multiple whitespaces as description):   ",
+    "ci no colon after type",
+    "test:  extra space after colon",
+    "ci:	tab after colon",
+    "ci:no space after colon",
+    "ci :extra space before colon",
+    "refactor(): empty scope",
+    "ci( ): whitespace as scope",
+    "chore: period at end of sentence.",
+    "ci: Starting sentence capitalized",
+    "unknown: using unknown type",
+    "chore: you're saying this commit message just goes on and on and on and on and on and on for way too long?",
+  }
+
+  p('Messages expected to pass:')
+
+  for _, message in ipairs(good_messages) do
+    if commit_message_is_ok(message) then
+      p('[ PASSED ] : '..message)
+    else
+      p('[ FAIL ]   : '..message)
+    end
+  end
+
+  p("Messages expected to fail:")
+
+  for _, message in ipairs(bad_messages) do
+    if commit_message_is_ok(message) then
+      p('[ PASSED ] : '..message)
+    else
+      p('[ FAIL ]   : '..message)
+    end
+  end
+end
+
+-- _test()
+main()