From 9f5e1157f03a96255bb2c674c338c1970edb5ae6 Mon Sep 17 00:00:00 2001
From: kochklops <kochklops@noreply.codeberg.org>
Date: Sat, 12 Jul 2025 16:00:42 +0200
Subject: [PATCH] feat: introduce global merge message templates (#8347)

Allow for a directory `default_merge_message` in the `CustomPath` to be used as a fallback if no merge template is specified by the repository. Effectively being a global merge message template feature.

Resolves #6648

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/8347
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: kochklops <kochklops@noreply.codeberg.org>
Co-committed-by: kochklops <kochklops@noreply.codeberg.org>
---
 models/repo/git.go                            |   2 +
 .../tests/repos/templates_repo/COMMIT_EDITMSG |   1 +
 modules/git/tests/repos/templates_repo/HEAD   |   1 +
 modules/git/tests/repos/templates_repo/config |   5 ++
 .../tests/repos/templates_repo/description    |   1 +
 modules/git/tests/repos/templates_repo/index  | Bin 0 -> 256 bytes
 .../tests/repos/templates_repo/info/exclude   |   6 ++
 .../git/tests/repos/templates_repo/info/refs  |   1 +
 .../templates_repo/objects/info/commit-graph  | Bin 0 -> 1172 bytes
 .../repos/templates_repo/objects/info/packs   |   2 +
 ...544ae19d590e95822e963f78d069d27ba9e.bitmap | Bin 0 -> 210 bytes
 ...b44544ae19d590e95822e963f78d069d27ba9e.idx | Bin 0 -> 1212 bytes
 ...44544ae19d590e95822e963f78d069d27ba9e.pack | Bin 0 -> 415 bytes
 .../tests/repos/templates_repo/packed-refs    |   2 +
 .../repos/templates_repo/refs/heads/.gitkeep  |   0
 .../repos/templates_repo/refs/tags/.gitkeep   |   0
 services/pull/check.go                        |   4 ++
 services/pull/merge.go                        |  31 ++++++++++
 services/pull/merge_test.go                   |  56 ++++++++++++++++++
 services/pull/pull_test.go                    |  36 +++++++++++
 20 files changed, 148 insertions(+)
 create mode 100644 modules/git/tests/repos/templates_repo/COMMIT_EDITMSG
 create mode 100644 modules/git/tests/repos/templates_repo/HEAD
 create mode 100644 modules/git/tests/repos/templates_repo/config
 create mode 100644 modules/git/tests/repos/templates_repo/description
 create mode 100644 modules/git/tests/repos/templates_repo/index
 create mode 100644 modules/git/tests/repos/templates_repo/info/exclude
 create mode 100644 modules/git/tests/repos/templates_repo/info/refs
 create mode 100644 modules/git/tests/repos/templates_repo/objects/info/commit-graph
 create mode 100644 modules/git/tests/repos/templates_repo/objects/info/packs
 create mode 100644 modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.bitmap
 create mode 100644 modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.idx
 create mode 100644 modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.pack
 create mode 100644 modules/git/tests/repos/templates_repo/packed-refs
 create mode 100644 modules/git/tests/repos/templates_repo/refs/heads/.gitkeep
 create mode 100644 modules/git/tests/repos/templates_repo/refs/tags/.gitkeep

diff --git a/models/repo/git.go b/models/repo/git.go
index 692176c8f6..11f6452be5 100644
--- a/models/repo/git.go
+++ b/models/repo/git.go
@@ -29,6 +29,8 @@ const (
 	MergeStyleRebaseUpdate MergeStyle = "rebase-update-only"
 )
 
+var MergeStyles = []MergeStyle{MergeStyleMerge, MergeStyleRebase, MergeStyleRebaseMerge, MergeStyleSquash, MergeStyleFastForwardOnly, MergeStyleManuallyMerged, MergeStyleRebaseUpdate}
+
 type UpdateStyle string
 
 const (
diff --git a/modules/git/tests/repos/templates_repo/COMMIT_EDITMSG b/modules/git/tests/repos/templates_repo/COMMIT_EDITMSG
new file mode 100644
index 0000000000..a77fa514de
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/COMMIT_EDITMSG
@@ -0,0 +1 @@
+Initial
diff --git a/modules/git/tests/repos/templates_repo/HEAD b/modules/git/tests/repos/templates_repo/HEAD
new file mode 100644
index 0000000000..cb089cd89a
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/HEAD
@@ -0,0 +1 @@
+ref: refs/heads/master
diff --git a/modules/git/tests/repos/templates_repo/config b/modules/git/tests/repos/templates_repo/config
new file mode 100644
index 0000000000..a4ef456cbc
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/config
@@ -0,0 +1,5 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+	logallrefupdates = true
diff --git a/modules/git/tests/repos/templates_repo/description b/modules/git/tests/repos/templates_repo/description
new file mode 100644
index 0000000000..498b267a8c
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/description
@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.
diff --git a/modules/git/tests/repos/templates_repo/index b/modules/git/tests/repos/templates_repo/index
new file mode 100644
index 0000000000000000000000000000000000000000..2b3f95a155afc685892e5395c5beab3e8686c212
GIT binary patch
literal 256
zcmZ?q402{*U|<4b#*FOq!CID0uV6G#%$^}PVH*QO;}Ql2<`)pmkSXq(c;LJO<1_8g
zf+kBAidJ6zR=keEKrb!7C_ObRUq2-^EwMDGBtAD4$On?e#fj;u`o69~?ym76uD$_2
zjv=mkxhV_`AwjOLKsz!R3>6Hy=7uEAxpqzK)7oYBOJ}efL`B~ylYkisRxl^_8DnFA
z)q0<hI?XBOISwB`9^8!8Dxhiut~U&tcVB*gx%+L=jtJlR!kcWT8b&C7O8GM-$=~ql
Q;@__yeKk0J_y6u$0QEd$@Bjb+

literal 0
HcmV?d00001

diff --git a/modules/git/tests/repos/templates_repo/info/exclude b/modules/git/tests/repos/templates_repo/info/exclude
new file mode 100644
index 0000000000..a5196d1be8
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/info/exclude
@@ -0,0 +1,6 @@
+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~
diff --git a/modules/git/tests/repos/templates_repo/info/refs b/modules/git/tests/repos/templates_repo/info/refs
new file mode 100644
index 0000000000..8ee4ab3ff8
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/info/refs
@@ -0,0 +1 @@
+45697427ce0595075c5c8efa42567f050208510d	refs/heads/master
diff --git a/modules/git/tests/repos/templates_repo/objects/info/commit-graph b/modules/git/tests/repos/templates_repo/objects/info/commit-graph
new file mode 100644
index 0000000000000000000000000000000000000000..8904092586212bddb42fc82d2a24a6e04b265c24
GIT binary patch
literal 1172
zcmZ>E5Aa}QWMT04ba7*V02d(J2f}1=advSGfwCjqT^x;|>>3CSB3T-M#3;ZF0Y;$E
zC>{-iVV?$EGfULZu})==iRt_06jsm5#1Y6lHzaA!wQE|R)-JPOI)mLHD*8s5L;)~E
kfG`lSWMrRT24bvxetJ^K;Ucl+;kn}C^R`V}dXb?707}dyvH$=8

literal 0
HcmV?d00001

diff --git a/modules/git/tests/repos/templates_repo/objects/info/packs b/modules/git/tests/repos/templates_repo/objects/info/packs
new file mode 100644
index 0000000000..5833126b59
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/objects/info/packs
@@ -0,0 +1,2 @@
+P pack-abb44544ae19d590e95822e963f78d069d27ba9e.pack
+
diff --git a/modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.bitmap b/modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.bitmap
new file mode 100644
index 0000000000000000000000000000000000000000..6bd87bf13c64a032d04deb620ed9b740bfca401d
GIT binary patch
literal 210
zcmZ?r4Dn@PWME}rU|?Lm#nok<<kbl;Ba~hyfA3|RtG;U<NF0cnpcqJj0Z0r4K>E<-
zWWX{AagaO=AhTg+z~mr&2Ot;SM0t>s=6OpaLG&bs8z73I-B5%nYvBR4BhFtY>=eDQ
Nr0IwKmc2YVPXOIH8_)m%

literal 0
HcmV?d00001

diff --git a/modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.idx b/modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.idx
new file mode 100644
index 0000000000000000000000000000000000000000..b530533e1b850a0d0334e687e2bae1987156bb01
GIT binary patch
literal 1212
zcmexg;-AdGz`z8=v;>Sm!-paUh07?WO&Bl(!<J<flN|=Ez_6nl7I#fNa9)A&nf7Nv
zlO+p9E3bYlUgw%wqJEBbDtk;!-!G@IdR8WmK;AjA&lnr~tJeF3)M-vJ&vE$p@!;mU
zAxU$tUDNuscA5Rs8SDm8(KpH@-Y{t1efj<6?zcrdB7ElyZ?c_g81cO0;GMKnlguwM
zwcmcL@gx563x)qcKlA`G53qQU2GZ|=bnxmet}g2&uTFRwq4YBOdoSBu^<DFByf$h3
Vw62-!*<FXTui|*8a$IuT0svC_SGNEF

literal 0
HcmV?d00001

diff --git a/modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.pack b/modules/git/tests/repos/templates_repo/objects/pack/pack-abb44544ae19d590e95822e963f78d069d27ba9e.pack
new file mode 100644
index 0000000000000000000000000000000000000000..6bbcbb6546fa9a72f8fb69b9102bb328e5b5830a
GIT binary patch
literal 415
zcmV;Q0bu@6K|@Ob00062000G$40xQS%smc+FbqK9J*UWC2_=B@BUM$`9>c^2A_7Kf
zI`sDK)C=@Y-}G8#){$UzeN5!Y^*HxP=!O{~2IB_<2onYGY*6@Wt5m&7TDKzSQ(u3)
zA5!@&?=A`P#C7SUE;nsG*bpK5QD4kAm1N&@Yy96uJ&xQm7WDy3ggu1026&uvNli;E
z%_&jHO)W}K1(L<Zi9os}HMbxqu_Tp?D<mVcSRp4fFIAyDu~?xfH8DjYttdZNK`$*I
zs39v~KLuhyJlKGEr~&%Eu0igu@gc6h0X~i)u6nsCTma|`B}$_Lc$_ma00ITQwEUv<
z)U14lIkC?e8~dx)`-IeKPBG7M`1tYQW&qVM4qTuEc$_ma00M=S)U?FXoRaw5)S~oM
zAX!|Tn4Ze;hC%c0%kM9Dzb)Dk;X7Y=lkHT)2mr(n6rQaDc$_mdFfcPQQSfyQa(9gn
zarF)GaSU<Q%S~YrcTGHSUV-tM_GdwpB@0C>uYN0D2LLIe5AUnAMMSO{)sX2}BI#rI
JjRu`3x}K3NxM%<X

literal 0
HcmV?d00001

diff --git a/modules/git/tests/repos/templates_repo/packed-refs b/modules/git/tests/repos/templates_repo/packed-refs
new file mode 100644
index 0000000000..eb6e7a8add
--- /dev/null
+++ b/modules/git/tests/repos/templates_repo/packed-refs
@@ -0,0 +1,2 @@
+# pack-refs with: peeled fully-peeled sorted 
+45697427ce0595075c5c8efa42567f050208510d refs/heads/master
diff --git a/modules/git/tests/repos/templates_repo/refs/heads/.gitkeep b/modules/git/tests/repos/templates_repo/refs/heads/.gitkeep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/modules/git/tests/repos/templates_repo/refs/tags/.gitkeep b/modules/git/tests/repos/templates_repo/refs/tags/.gitkeep
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/services/pull/check.go b/services/pull/check.go
index 6002e2ae26..c31d107605 100644
--- a/services/pull/check.go
+++ b/services/pull/check.go
@@ -404,6 +404,10 @@ func CheckPRsForBaseBranch(ctx context.Context, baseRepo *repo_model.Repository,
 
 // Init runs the task queue to test all the checking status pull requests
 func Init() error {
+	if err := LoadMergeMessageTemplates(); err != nil {
+		return err
+	}
+
 	prPatchCheckerQueue = queue.CreateUniqueQueue(graceful.GetManager().ShutdownContext(), "pr_patch_checker", handler)
 
 	if prPatchCheckerQueue == nil {
diff --git a/services/pull/merge.go b/services/pull/merge.go
index f69f8a87b4..55ce869497 100644
--- a/services/pull/merge.go
+++ b/services/pull/merge.go
@@ -35,6 +35,30 @@ import (
 	notify_service "forgejo.org/services/notify"
 )
 
+var mergeMessageTemplates = make(map[repo_model.MergeStyle]string, len(repo_model.MergeStyles))
+
+func LoadMergeMessageTemplates() error {
+	// Load templates for all known merge styles
+	for _, mergeStyle := range repo_model.MergeStyles {
+		templateFilename := filepath.Join(
+			setting.CustomPath,
+			"default_merge_message",
+			fmt.Sprintf("%s_TEMPLATE.md", strings.ToUpper(string(mergeStyle))),
+		)
+
+		content, err := os.ReadFile(templateFilename)
+		if err == nil {
+			mergeMessageTemplates[mergeStyle] = string(content)
+		} else if os.IsNotExist(err) {
+			// The file no longer exists, so delete any previous content
+			delete(mergeMessageTemplates, mergeStyle)
+		} else {
+			return err
+		}
+	}
+	return nil
+}
+
 // getMergeMessage composes the message used when merging a pull request.
 func getMergeMessage(ctx context.Context, baseGitRepo *git.Repository, pr *issues_model.PullRequest, mergeStyle repo_model.MergeStyle, extraVars map[string]string) (message, body string, err error) {
 	if err := pr.LoadBaseRepo(ctx); err != nil {
@@ -79,6 +103,13 @@ func getMergeMessage(ctx context.Context, baseGitRepo *git.Repository, pr *issue
 		if _, ok := err.(git.ErrNotExist); ok {
 			templateContent, err = commit.GetFileContent(templateFilepathGitea, setting.Repository.PullRequest.DefaultMergeMessageSize)
 		}
+
+		if _, ok := err.(git.ErrNotExist); ok {
+			if preloadedContent, ok := mergeMessageTemplates[mergeStyle]; ok {
+				templateContent, err = preloadedContent, nil
+			}
+		}
+
 		if err != nil {
 			if !git.IsErrNotExist(err) {
 				return "", "", err
diff --git a/services/pull/merge_test.go b/services/pull/merge_test.go
index 2a26759956..3684c2120a 100644
--- a/services/pull/merge_test.go
+++ b/services/pull/merge_test.go
@@ -4,9 +4,17 @@
 package pull
 
 import (
+	"os"
+	"path"
+	"strings"
 	"testing"
 
+	repo_model "forgejo.org/models/repo"
+	"forgejo.org/modules/setting"
+	"forgejo.org/modules/test"
+
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func Test_expandDefaultMergeMessage(t *testing.T) {
@@ -90,3 +98,51 @@ func TestAddCommitMessageTailer(t *testing.T) {
 	assert.Equal(t, "title\n\nTest-tailer: v1\nTest-tailer: v2", AddCommitMessageTrailer("title\n\nTest-tailer: v1", "Test-tailer", "v2"))
 	assert.Equal(t, "title\n\nTest-tailer: v1\nTest-tailer: v2", AddCommitMessageTrailer("title\n\nTest-tailer: v1\n", "Test-tailer", "v2"))
 }
+
+func prepareLoadMergeMessageTemplates(targetDir string) error {
+	for _, template := range []string{"MERGE", "REBASE", "REBASE-MERGE", "SQUASH", "MANUALLY-MERGED", "REBASE-UPDATE-ONLY"} {
+		file, err := os.Create(path.Join(targetDir, template+"_TEMPLATE.md"))
+		defer file.Close()
+
+		if err == nil {
+			_, err = file.WriteString("Contents for " + template)
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func TestLoadMergeMessageTemplates(t *testing.T) {
+	defer test.MockVariableValue(&setting.CustomPath, t.TempDir())()
+	templateTemp := path.Join(setting.CustomPath, "default_merge_message")
+
+	require.NoError(t, os.MkdirAll(templateTemp, 0o755))
+	require.NoError(t, prepareLoadMergeMessageTemplates(templateTemp))
+
+	testStyles := []repo_model.MergeStyle{
+		repo_model.MergeStyleMerge,
+		repo_model.MergeStyleRebase,
+		repo_model.MergeStyleRebaseMerge,
+		repo_model.MergeStyleSquash,
+		repo_model.MergeStyleManuallyMerged,
+		repo_model.MergeStyleRebaseUpdate,
+	}
+
+	// Load all templates
+	require.NoError(t, LoadMergeMessageTemplates())
+
+	// Check their correctness
+	assert.Len(t, mergeMessageTemplates, len(testStyles))
+	for _, mergeStyle := range testStyles {
+		assert.Equal(t, "Contents for "+strings.ToUpper(string(mergeStyle)), mergeMessageTemplates[mergeStyle])
+	}
+
+	// Unload all templates
+	require.NoError(t, os.RemoveAll(templateTemp))
+	require.NoError(t, LoadMergeMessageTemplates())
+	assert.Empty(t, mergeMessageTemplates)
+}
diff --git a/services/pull/pull_test.go b/services/pull/pull_test.go
index 010b7a6404..99607c5b35 100644
--- a/services/pull/pull_test.go
+++ b/services/pull/pull_test.go
@@ -92,3 +92,39 @@ func TestPullRequest_GetDefaultMergeMessage_ExternalTracker(t *testing.T) {
 
 	assert.Equal(t, "Merge pull request 'issue3' (#3) from user2/repo2:branch2 into master", mergeMessage)
 }
+
+func TestPullRequest_GetDefaultMergeMessage_GlobalTemplate(t *testing.T) {
+	require.NoError(t, unittest.PrepareTestDatabase())
+	pr := unittest.AssertExistsAndLoadBean(t, &issues_model.PullRequest{ID: 2})
+
+	require.NoError(t, pr.LoadBaseRepo(t.Context()))
+	gitRepo, err := gitrepo.OpenRepository(t.Context(), pr.BaseRepo)
+	require.NoError(t, err)
+	defer gitRepo.Close()
+
+	templateRepo, err := git.OpenRepository(t.Context(), "./../../modules/git/tests/repos/templates_repo")
+	require.NoError(t, err)
+	defer templateRepo.Close()
+
+	mergeMessageTemplates[repo_model.MergeStyleMerge] = "${PullRequestTitle} (${PullRequestReference})\n${PullRequestDescription}"
+
+	// Check template is used for Merge...
+	mergeMessage, body, err := GetDefaultMergeMessage(t.Context(), gitRepo, pr, repo_model.MergeStyleMerge)
+	require.NoError(t, err)
+
+	assert.Equal(t, "issue3 (#3)", mergeMessage)
+	assert.Equal(t, "content for the third issue", body)
+
+	// ...but not for RebaseMerge
+	mergeMessage, _, err = GetDefaultMergeMessage(t.Context(), gitRepo, pr, repo_model.MergeStyleRebaseMerge)
+	require.NoError(t, err)
+
+	assert.Equal(t, "Merge pull request 'issue3' (#3) from branch2 into master", mergeMessage)
+
+	// ...and that custom Merge template takes priority
+	mergeMessage, body, err = GetDefaultMergeMessage(t.Context(), templateRepo, pr, repo_model.MergeStyleMerge)
+	require.NoError(t, err)
+
+	assert.Equal(t, "Default merge message template", mergeMessage)
+	assert.Equal(t, "This line was read from .forgejo/default_merge_message/MERGE_TEMPLATE.md", body)
+}