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Fix: a push of another branch no longer resets the default branch

1e5369d · Gabriel Morell · 2026-10-22 22:49

✓ build / android (push) ✓ build / build (push) ✓ build / cli (push) ✓ build / deb (push) ✓ dependency-updates / update (workflow_dispatch) ✓ hello / smoke (push)

9 files +131 -11

Message

{commit_body(@commit)}

Files changed

modified lib/git_gud/repositories.ex

+3 −0

@@ -1765,6 +1765,9 @@ defmodule GitGud.Repositories do

1765	1765	\|> tap(fn
1766	1766	# `on: schedule` follows the default branch.
1767	1767	{:ok, %Repository{default_branch: branch} = updated} when branch != repo.default_branch ->
	1768	+ # The bare repository's HEAD follows, so a clone checks out
	1769	+ # the default and nothing reading HEAD disagrees with it.
	1770	+ :ok = set_default_head(updated.disk_path, branch)
1768	1771	{:ok, _count} = GitGud.Workflows.Schedules.sync(updated)
1769	1772
1770	1773	_ ->

modified lib/git_gud/repositories/hook_receiver.ex

+54 −11

@@ -61,10 +61,17 @@ defmodule GitGud.Repositories.HookReceiver do

61	61	end
62	62	end
63	63
64		− # If the repo's recorded default_branch no longer resolves on disk
	64	+ # If the repo's recorded default_branch doesn't resolve on disk
65	65	# (typical: empty repo created with default "main", first push lands
66	66	# on "master"), align default_branch with HEAD so the UI doesn't
67	67	# render "This repository is empty" against a populated repo.
	68	+ #
	69	+ # Only then: a push that simply doesn't touch the default branch — a
	70	+ # feature branch, a CI job's update branch — says nothing about which
	71	+ # branch is the default, and a bare HEAD left at git's own "main" must
	72	+ # not overwrite a configured "master" that exists. Where the
	73	+ # configured branch does exist, HEAD is pointed at it instead, so the
	74	+ # two stop disagreeing.
68	75	defp sync_default_branch_if_unset(repository_id, triples) do
69	76	repo = GitGud.Repo.get(Repository, repository_id)
70	77

@@ -74,20 +81,56 @@ defmodule GitGud.Repositories.HookReceiver do

74	81	configured_pushed? =
75	82	Enum.any?(triples, fn {_, _, ref} -> ref == configured end)
76	83
77		− unless configured_pushed? do
78		− case read_head_branch(repo.disk_path) do
79		− {:ok, branch} when branch != repo.default_branch ->
80		− repo
81		− \|> Ecto.Changeset.change(default_branch: branch)
82		− \|> GitGud.Repo.update()
83		−
84		− _ ->
85		− :ok
86		− end
	84	+ cond do
	85	+ configured_pushed? ->
	86	+ :ok
	87	+
	88	+ branch_exists?(repo.disk_path, configured) ->
	89	+ point_head_at(repo.disk_path, configured)
	90	+
	91	+ true ->
	92	+ case read_head_branch(repo.disk_path) do
	93	+ {:ok, branch} when branch != repo.default_branch ->
	94	+ if branch_exists?(repo.disk_path, "refs/heads/" <> branch) do
	95	+ repo
	96	+ \|> Ecto.Changeset.change(default_branch: branch)
	97	+ \|> GitGud.Repo.update()
	98	+ end
	99	+
	100	+ _ ->
	101	+ :ok
	102	+ end
87	103	end
88	104	end
89	105	end
90	106
	107	+ defp branch_exists?(disk_path, "refs/heads/" <> name = ref) when name != "" do
	108	+ match?(
	109	+ {_, 0},
	110	+ System.cmd("git", ["-C", disk_path, "rev-parse", "--verify", "--quiet", ref <> "^{commit}"],
	111	+ stderr_to_stdout: true
	112	+ )
	113	+ )
	114	+ end
	115	+
	116	+ defp branch_exists?(_disk_path, _ref), do: false
	117	+
	118	+ defp point_head_at(disk_path, ref) do
	119	+ case File.read(Path.join(disk_path, "HEAD")) do
	120	+ {:ok, "ref: " <> current} when current != "" ->
	121	+ if String.trim(current) != ref,
	122	+ do:
	123	+ System.cmd("git", ["-C", disk_path, "symbolic-ref", "HEAD", ref],
	124	+ stderr_to_stdout: true
	125	+ )
	126	+
	127	+ _ ->
	128	+ :ok
	129	+ end
	130	+
	131	+ :ok
	132	+ end
	133	+
91	134	# Stamp pushed_at so repo listings can show "pushed N ago". Skip
92	135	# delete-only pushes (all triples have a zero new SHA) since they
93	136	# aren't really a push of content.

added test/git_gud/repositories/default_branch_sync_test.exs

+74 −0

@@ -0,0 +1,74 @@

	1	+defmodule GitGud.Repositories.DefaultBranchSyncTest do
	2	+ @moduledoc """
	3	+ What a push may do to a repository's default branch: realign it with
	4	+ the bare repository's HEAD when the configured one doesn't exist (an
	5	+ empty repo made as "main", first pushed as "master") — and nothing
	6	+ when it does, however HEAD reads. A push of some other branch once
	7	+ reset a configured, existing "master" to a "main" no one had.
	8	+ """
	9	+ use GitGud.DataCase, async: false
	10	+
	11	+ import GitGud.ForgeFixtures
	12	+ import GitGud.WorkflowGitHelpers
	13	+
	14	+ alias GitGud.Repositories
	15	+ alias GitGud.Repositories.HookReceiver
	16	+ alias GitGud.Repositories.Repository
	17	+
	18	+ @zero String.duplicate("0", 40)
	19	+
	20	+ defp push(repo, branch, sha),
	21	+ do: HookReceiver.receive(repo.id, "#{@zero} #{sha} refs/heads/#{branch}\n")
	22	+
	23	+ defp head(repo), do: repo.disk_path \|> Path.join("HEAD") \|> File.read!() \|> String.trim()
	24	+
	25	+ setup do
	26	+ {_owner, repo} = repository_fixture()
	27	+ main = commit!(repo, %{"a" => "a\n"}, [])
	28	+ {:ok, repo: repo, sha: main}
	29	+ end
	30	+
	31	+ test "another branch's push leaves an existing default alone, and HEAD follows it", %{
	32	+ repo: repo,
	33	+ sha: sha
	34	+ } do
	35	+ repo = Repo.update!(Ecto.Changeset.change(repo, default_branch: "master"))
	36	+ git!(repo.disk_path, ["update-ref", "refs/heads/master", sha])
	37	+ git!(repo.disk_path, ["update-ref", "refs/heads/deps/security-hex", sha])
	38	+ # git's own default, as an old bare repo may still have it.
	39	+ git!(repo.disk_path, ["symbolic-ref", "HEAD", "refs/heads/main"])
	40	+
	41	+ push(repo, "deps/security-hex", sha)
	42	+
	43	+ assert Repo.get!(Repository, repo.id).default_branch == "master"
	44	+ assert head(repo) == "ref: refs/heads/master"
	45	+ end
	46	+
	47	+ test "a default that doesn't exist is realigned with HEAD", %{repo: repo, sha: sha} do
	48	+ repo = Repo.update!(Ecto.Changeset.change(repo, default_branch: "main"))
	49	+ git!(repo.disk_path, ["update-ref", "refs/heads/master", sha])
	50	+ git!(repo.disk_path, ["symbolic-ref", "HEAD", "refs/heads/master"])
	51	+
	52	+ push(repo, "master", sha)
	53	+
	54	+ assert Repo.get!(Repository, repo.id).default_branch == "master"
	55	+ end
	56	+
	57	+ test "…but not to a HEAD that doesn't exist either", %{repo: repo, sha: sha} do
	58	+ repo = Repo.update!(Ecto.Changeset.change(repo, default_branch: "trunk"))
	59	+ git!(repo.disk_path, ["update-ref", "refs/heads/feature", sha])
	60	+ git!(repo.disk_path, ["symbolic-ref", "HEAD", "refs/heads/main"])
	61	+
	62	+ push(repo, "feature", sha)
	63	+
	64	+ assert Repo.get!(Repository, repo.id).default_branch == "trunk"
	65	+ end
	66	+
	67	+ test "changing the default in settings points HEAD at it", %{repo: repo, sha: sha} do
	68	+ git!(repo.disk_path, ["update-ref", "refs/heads/trunk", sha])
	69	+
	70	+ {:ok, _} = Repositories.update_repository(repo, %{"default_branch" => "trunk"})
	71	+
	72	+ assert head(repo) == "ref: refs/heads/trunk"
	73	+ end
	74	+end

Parents: c91f312