feat: new git module to work with branches, tags & versions

lua/lazy/manage/git.lua

@@ -0,0 +1,94 @@
+local Util = require("lazy.util")
+local Semver = require("lazy.manage.semver")
+
+local M = {}
+
+---@param details? boolean
+function M.info(repo, details)
+  local line = Util.head(repo .. "/.git/HEAD")
+  if line then
+    ---@type string, string
+    local ref, branch = line:match("ref: (refs/heads/(.*))")
+    local ret = ref and {
+      branch = branch,
+      commit = Util.head(repo .. "/.git/" .. ref),
+    } or { commit = line }
+
+    if details then
+      Util.ls(repo .. "/.git/refs/tags", function(_, name)
+        if M.ref(repo, "tags/" .. name) == ret.commit then
+          ret.tag = name
+          ret.version = Semver.version(name)
+          return false
+        end
+      end)
+    end
+
+    return ret
+  end
+end
+
+---@class TaggedSemver: Semver
+---@field tag string
+
+---@param spec? string
+function M.get_versions(repo, spec)
+  local range = Semver.range(spec or "*")
+  ---@type TaggedSemver[]
+  local versions = {}
+  Util.ls(repo .. "/.git/refs/tags", function(_, name)
+    local v = Semver.version(name)
+    ---@cast v TaggedSemver
+    if v and range:matches(v) then
+      v.tag = name
+      table.insert(versions, v)
+    end
+  end)
+  return versions
+end
+
+---@param plugin LazyPlugin
+function M.get_branch(plugin)
+  if plugin.branch then
+    return {
+      branch = plugin.branch,
+      commit = M.ref(plugin.dir, "heads/" .. plugin.branch),
+    }
+  else
+    local main = M.ref(plugin.dir, "remotes/origin/HEAD")
+    if main then
+      local branch = main:match("ref: refs/remotes/origin/(.*)")
+      if branch then
+        return {
+          branch = branch,
+          commit = M.ref(plugin.dir, "heads/" .. branch),
+        }
+      end
+    end
+  end
+end
+
+---@param plugin LazyPlugin
+function M.get_target(plugin)
+  local branch = M.get_branch(plugin)
+
+  if plugin.commit then
+    return { branch = branch, commit = plugin.commit }
+  end
+  if plugin.tag then
+    return { branch = branch, tag = plugin.tag, commit = M.ref(plugin.dir, "tags/" .. plugin.tag) }
+  end
+  if plugin.version then
+    local last = Semver.last(M.get_versions(plugin.dir, plugin.version))
+    if last then
+      return { branch = branch, version = last, tag = last.tag, commit = M.ref(plugin.dir, "tags/" .. last.tag) }
+    end
+  end
+  return { branch = branch, commit = branch.commit }
+end
+
+function M.ref(repo, ref)
+  return Util.head(repo .. "/.git/refs/" .. ref)
+end
+
+return M