EXAMPLE-HOOKS: Add history-must-be-merges.update.lua example

1 files changed, 29 insertions, 0 deletions

diff --git a/example/example-hooks/history-must-be-merges.update.lua b/example/example-hooks/history-must-be-merges.update.lua
new file mode 100644
index 0000000..9cac773
--- /dev/null
+++ b/example/example-hooks/history-must-be-merges.update.lua
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+-- history-must-be-merges.update.lua
+--
+-- Example for hooks/update.lua in a project which ensures that all
+-- branches (refs/heads/...) only ever get merge commits.
+--
+-- Copyright 2012 Daniel Silverstone <dsilvers@digital-scurf.org>
+--
+
+local repo, ref, oldsha, newsha = ...
+
+local branch = ref:match("^refs/heads/(.+)$")
+if branch then
+   log.state("Looking at commit history on: " .. branch)
+
+   local commit = repo:get(newsha)
+
+   while commit.sha ~= oldsha do
+      commit = commit.content
+      local parents = commit.parents
+      if #parents < 2 then
+	 error("Detected non-merge-commit during parent walk, at " .. commit.sha)
+      end
+      commit = parents[1]
+   end
+   
+   log.state("Commits between old and new sha seem to all be merge commits")
+else
+   log.state("Skipping commit history check on: " .. ref)
+end