fix(ci): run push workflows when a push brings no new commit

A new branch at an existing commit, or a branch rewound to an ancestor, gave
an empty range and an error that wrapped nil, so nothing ran. The head commit
is read alone, with no changed file, as GitHub does.

commit: 5aba7f2d3064eea6e191baff2b30481aa8908126
author: brice · 9d ago · 2026-10-12 19:07 UTC
parent: cfd70eb
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +43 -2

M internal/app/ci_flow_test.go +24 -0


@@ -556,3 +556,27 @@ func TestCIEventsAreStreamedOnTheRepositoryTopic(t *testing.T) {
556	556		require.NoError(t, err)
557	557		c.sentinel(t, home, "sentinel")
558	558		}
	559	+
	560	+	// A new branch at a commit that already exists, and a branch rewound to an
	561	+	// ancestor, bring no new commit: GitHub still runs the push workflows (those
	562	+	// without a paths filter, as no file changed).
	563	+	func TestCIPushWithoutNewCommitsStillRuns(t *testing.T) {
	564	+	c := newCIHarness(t, nil)
	565	+	c.registerRunner("alpha", "ubuntu-latest")
	566	+	c.push("main", map[string]string{".github/workflows/any.yml": workflowWith("branches: ['**']")}, "")
	567	+	c.waitFor("main runs", func() bool { return len(c.runs()) == 1 })
	568	+	first := strings.TrimSpace(c.mustGit(c.wt, "rev-parse", "HEAD"))
	569	+
	570	+	// A new branch at the commit main already has.
	571	+	c.mustGit(c.wt, "push", "-q", c.urlAuth(adminToken, "/proj.git"), "HEAD:refs/heads/same")
	572	+	c.waitFor("the new branch runs", func() bool { return len(c.runs()) == 2 })
	573	+	assert.Equal(t, "refs/heads/same", c.runs()[0].GetRef())
	574	+	assert.Equal(t, first, c.runs()[0].GetSha())
	575	+
	576	+	// A branch moved forward, then rewound to its ancestor (a forced push).
	577	+	c.push("main", map[string]string{"a.txt": "a\n"}, "")
	578	+	c.waitFor("the push runs", func() bool { return len(c.runs()) == 3 })
	579	+	c.mustGit(c.wt, "push", "-q", "-f", c.urlAuth(adminToken, "/proj.git"), first+":refs/heads/main")
	580	+	c.waitFor("the rewind runs", func() bool { return len(c.runs()) == 4 })
	581	+	assert.Equal(t, first, c.runs()[0].GetSha())
	582	+	}


@@ -556,3 +556,27 @@ func TestCIEventsAreStreamedOnTheRepositoryTopic(t *testing.T) {
556	require.NoError(t, err)	556		require.NoError(t, err)
557	c.sentinel(t, home, "sentinel")	557		c.sentinel(t, home, "sentinel")
558	}	558		}
		559	+
		560	+	// A new branch at a commit that already exists, and a branch rewound to an
		561	+	// ancestor, bring no new commit: GitHub still runs the push workflows (those
		562	+	// without a paths filter, as no file changed).
		563	+	func TestCIPushWithoutNewCommitsStillRuns(t *testing.T) {
		564	+	c := newCIHarness(t, nil)
		565	+	c.registerRunner("alpha", "ubuntu-latest")
		566	+	c.push("main", map[string]string{".github/workflows/any.yml": workflowWith("branches: ['**']")}, "")
		567	+	c.waitFor("main runs", func() bool { return len(c.runs()) == 1 })
		568	+	first := strings.TrimSpace(c.mustGit(c.wt, "rev-parse", "HEAD"))
		569	+
		570	+	// A new branch at the commit main already has.
		571	+	c.mustGit(c.wt, "push", "-q", c.urlAuth(adminToken, "/proj.git"), "HEAD:refs/heads/same")
		572	+	c.waitFor("the new branch runs", func() bool { return len(c.runs()) == 2 })
		573	+	assert.Equal(t, "refs/heads/same", c.runs()[0].GetRef())
		574	+	assert.Equal(t, first, c.runs()[0].GetSha())
		575	+
		576	+	// A branch moved forward, then rewound to its ancestor (a forced push).
		577	+	c.push("main", map[string]string{"a.txt": "a\n"}, "")
		578	+	c.waitFor("the push runs", func() bool { return len(c.runs()) == 3 })
		579	+	c.mustGit(c.wt, "push", "-q", "-f", c.urlAuth(adminToken, "/proj.git"), first+":refs/heads/main")
		580	+	c.waitFor("the rewind runs", func() bool { return len(c.runs()) == 4 })
		581	+	assert.Equal(t, first, c.runs()[0].GetSha())
		582	+	}

M internal/usecase/ci_trigger.go +19 -2


@@ -177,9 +177,12 @@ func (c *CI) collect(ctx context.Context, repo domain.RepoName, u domain.RefUpda
177	177		f.commit = res.CommitID
178	178		if isTag {
179	179		cs, _, err := c.cfg.Git.ListRange(ctx, repo, domain.ObjectID{}, f.commit, 1)
180		-	if err != nil \|\| len(cs) == 0 {
	180	+	if err != nil {
181	181		return f, fmt.Errorf("read the commit of the tag: %w", err)
182	182		}
	183	+	if len(cs) == 0 {
	184	+	return f, fmt.Errorf("read the commit of the tag: %w", domain.ErrNotFound)
	185	+	}
183	186		f.head = cs[0]
184	187		return f, nil
185	188		}

@@ -199,9 +202,23 @@ func (c *CI) collect(ctx context.Context, repo domain.RepoName, u domain.RefUpda
199	202		exclude = base
200	203		}
201	204		cs, more, err := c.cfg.Git.ListRange(ctx, repo, exclude, f.commit, ports.MaxCommitLimit)
202		-	if err != nil \|\| len(cs) == 0 {
	205	+	if err != nil {
203	206		return f, fmt.Errorf("read the commits of the push: %w", err)
204	207		}
	208	+	if len(cs) == 0 {
	209	+	// A new branch at a commit the default branch has, or a branch rewound
	210	+	// to an ancestor: no new commit, no changed file. GitHub still runs
	211	+	// the push workflows that have no paths filter, for the head commit.
	212	+	head, _, err := c.cfg.Git.ListRange(ctx, repo, domain.ObjectID{}, f.commit, 1)
	213	+	if err != nil {
	214	+	return f, fmt.Errorf("read the head commit of the push: %w", err)
	215	+	}
	216	+	if len(head) == 0 {
	217	+	return f, fmt.Errorf("read the head commit of the push: %w", domain.ErrNotFound)
	218	+	}
	219	+	f.head = head[0]
	220	+	return f, nil
	221	+	}
205	222		f.head = cs[0]
206	223		n := min(len(cs), maxPushCommits)
207	224		f.commits = slices.Clone(cs[:n])

 	f.commit = res.CommitID
 	if isTag {
 		cs, _, err := c.cfg.Git.ListRange(ctx, repo, domain.ObjectID{}, f.commit, 1)
-		if err != nil || len(cs) == 0 {
+		if err != nil {
 			return f, fmt.Errorf("read the commit of the tag: %w", err)
 		}
+		if len(cs) == 0 {
+			return f, fmt.Errorf("read the commit of the tag: %w", domain.ErrNotFound)
+		}
 		f.head = cs[0]
 		return f, nil
 	}
 		exclude = base
 	}
 	cs, more, err := c.cfg.Git.ListRange(ctx, repo, exclude, f.commit, ports.MaxCommitLimit)
-	if err != nil || len(cs) == 0 {
+	if err != nil {
 		return f, fmt.Errorf("read the commits of the push: %w", err)
 	}
+	if len(cs) == 0 {
+		// A new branch at a commit the default branch has, or a branch rewound
+		// to an ancestor: no new commit, no changed file. GitHub still runs
+		// the push workflows that have no paths filter, for the head commit.
+		head, _, err := c.cfg.Git.ListRange(ctx, repo, domain.ObjectID{}, f.commit, 1)
+		if err != nil {
+			return f, fmt.Errorf("read the head commit of the push: %w", err)
+		}
+		if len(head) == 0 {
+			return f, fmt.Errorf("read the head commit of the push: %w", domain.ErrNotFound)
+		}
+		f.head = head[0]
+		return f, nil
+	}
 	f.head = cs[0]
 	n := min(len(cs), maxPushCommits)
 	f.commits = slices.Clone(cs[:n])