[v11.0/forgejo] fix: package_blob.has_blake2b may be null (#7521)

**Backport:** https://codeberg.org/forgejo/forgejo/pulls/7520

- When looking for an existing blob, has_blake2b will be null when it was created prior to v26 migration in v11, when the field was introduced.
- Add unit test and minimal refactoring to load fixtures. The AddFixture function should not be where it currently is because it cannot be used by some packages (circular import). But that's a refactor that needs to be elsewhere for backporting purposes.

Fixes https://codeberg.org/forgejo/forgejo/issues/7519

When the fix is missing, the test fails like so:

```
--- FAIL: TestPackagesGetOrInsertBlob (0.03s)
    --- FAIL: TestPackagesGetOrInsertBlob/exists_and_blake2b_is_null_in_the_database (0.00s)
        package_blob_test.go:55:
            	Error Trace:	/home/earl-warren/software/forgejo/models/packages/package_blob_test.go:55
            	Error:      	Not equal:
            	            	expected: true
            	            	actual  : false
            	Test:       	TestPackagesGetOrInsertBlob/exists_and_blake2b_is_null_in_the_database
        package_blob_test.go:56:
            	Error Trace:	/home/earl-warren/software/forgejo/models/packages/package_blob_test.go:56
            	Error:      	Expected value not to be nil.
            	Test:       	TestPackagesGetOrInsertBlob/exists_and_blake2b_is_null_in_the_database
```

## Checklist

The [contributor guide](https://forgejo.org/docs/next/contributor/) contains information that will be helpful to first time contributors. There also are a few [conditions for merging Pull Requests in Forgejo repositories](https://codeberg.org/forgejo/governance/src/branch/main/PullRequestsAgreement.md). You are also welcome to join the [Forgejo development chatroom](https://matrix.to/#/#forgejo-development:matrix.org).

### Tests

- I added test coverage for Go changes...
  - [x] in their respective `*_test.go` for unit tests.
  - [ ] in the `tests/integration` directory if it involves interactions with a live Forgejo server.
- I added test coverage for JavaScript changes...
  - [ ] in `web_src/js/*.test.js` if it can be unit tested.
  - [ ] in `tests/e2e/*.test.e2e.js` if it requires interactions with a live Forgejo server (see also the [developer guide for JavaScript testing](https://codeberg.org/forgejo/forgejo/src/branch/forgejo/tests/e2e/README.md#end-to-end-tests)).

### Documentation

- [ ] I created a pull request [to the documentation](https://codeberg.org/forgejo/docs) to explain to Forgejo users how to use this change.
- [x] I did not document these changes and I do not expect someone else to do it.

### Release notes

- [x] I do not want this change to show in the release notes.
- [ ] I want the title to show in the release notes with a link to this pull request.
- [ ] I want the content of the `release-notes/<pull request number>.md` to be be used for the release notes instead of the title.

Co-authored-by: Earl Warren <contact@earl-warren.org>
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7521
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>
Co-committed-by: forgejo-backport-action <forgejo-backport-action@noreply.codeberg.org>

models/fixtures/TestPackagesGetOrInsertBlob/package_blob.yml

@@ -0,0 +1,17 @@
+-
+  id: 1
+  size: 10
+  hash_md5: HASHMD5_1
+  hash_sha1: HASHSHA1_1
+  hash_sha256: HASHSHA256_1
+  hash_sha512: HASHSHA512_1
+  hash_blake2b: HASHBLAKE2B_1
+  created_unix: 946687980
+-
+  id: 2
+  size: 20
+  hash_md5: HASHMD5_2
+  hash_sha1: HASHSHA1_2
+  hash_sha256: HASHSHA256_2
+  hash_sha512: HASHSHA512_2
+  created_unix: 946687980

models/packages/main_test.go

@@ -0,0 +1,31 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package packages
+
+import (
+	"path/filepath"
+	"testing"
+
+	"forgejo.org/models/unittest"
+	"forgejo.org/modules/setting"
+
+	_ "forgejo.org/models"
+	_ "forgejo.org/models/actions"
+	_ "forgejo.org/models/activities"
+	_ "forgejo.org/models/forgefed"
+)
+
+func AddFixtures(dirs ...string) func() {
+	return unittest.OverrideFixtures(
+		unittest.FixturesOptions{
+			Dir:  filepath.Join(setting.AppWorkPath, "models/fixtures/"),
+			Base: setting.AppWorkPath,
+			Dirs: dirs,
+		},
+	)
+}
+
+func TestMain(m *testing.M) {
+	unittest.MainTest(m)
+}

models/packages/package_blob.go

@@ -44,14 +44,19 @@ func GetOrInsertBlob(ctx context.Context, pb *PackageBlob) (*PackageBlob, bool,
 
 	existing := &PackageBlob{}
 
-	has, err := e.Where(builder.Eq{
+	has, err := e.Where(builder.And(
+		builder.Eq{
 			"size":        pb.Size,
 			"hash_md5":    pb.HashMD5,
 			"hash_sha1":   pb.HashSHA1,
 			"hash_sha256": pb.HashSHA256,
 			"hash_sha512": pb.HashSHA512,
-		"hash_blake2b": pb.HashBlake2b,
+		},
-	}).Get(existing)
+		builder.Or(
+			builder.Eq{"hash_blake2b": pb.HashBlake2b},
+			builder.IsNull{"hash_blake2b"},
+		),
+	)).Get(existing)
 	if err != nil {
 		return nil, false, err
 	}

models/packages/package_blob_test.go

@@ -0,0 +1,64 @@
+// Copyright 2025 The Forgejo Authors.
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package packages
+
+import (
+	"testing"
+
+	"forgejo.org/models/unittest"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPackagesGetOrInsertBlob(t *testing.T) {
+	defer AddFixtures("models/fixtures/TestPackagesGetOrInsertBlob/")()
+	require.NoError(t, unittest.PrepareTestDatabase())
+
+	blake2bIsSet := unittest.AssertExistsAndLoadBean(t, &PackageBlob{ID: 1})
+	blake2bNotSet := unittest.AssertExistsAndLoadBean(t, &PackageBlob{ID: 2})
+
+	blake2bSetToRandom := *blake2bNotSet
+	blake2bSetToRandom.HashBlake2b = "SOMETHING RANDOM"
+
+	for _, testCase := range []struct {
+		name        string
+		exists      bool
+		packageBlob *PackageBlob
+	}{
+		{
+			name:        "exists and blake2b is not null in the database",
+			exists:      true,
+			packageBlob: blake2bIsSet,
+		},
+		{
+			name:        "exists and blake2b is null in the database",
+			exists:      true,
+			packageBlob: &blake2bSetToRandom,
+		},
+		{
+			name:   "does not exists",
+			exists: false,
+			packageBlob: &PackageBlob{
+				Size:        30,
+				HashMD5:     "HASHMD5_3",
+				HashSHA1:    "HASHSHA1_3",
+				HashSHA256:  "HASHSHA256_3",
+				HashSHA512:  "HASHSHA512_3",
+				HashBlake2b: "HASHBLAKE2B_3",
+			},
+		},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			found, has, _ := GetOrInsertBlob(t.Context(), testCase.packageBlob)
+			assert.Equal(t, testCase.exists, has)
+			require.NotNil(t, found)
+			if testCase.exists {
+				assert.Equal(t, found.ID, testCase.packageBlob.ID)
+			} else {
+				unittest.BeanExists(t, &PackageBlob{ID: found.ID})
+			}
+		})
+	}
+}

models/packages/package_test.go

@@ -13,18 +13,9 @@ import (
 	"forgejo.org/models/unittest"
 	user_model "forgejo.org/models/user"
 
-	_ "forgejo.org/models"
-	_ "forgejo.org/models/actions"
-	_ "forgejo.org/models/activities"
-	_ "forgejo.org/models/forgefed"
-
 	"github.com/stretchr/testify/require"
 )
 
-func TestMain(m *testing.M) {
-	unittest.MainTest(m)
-}
-
 func prepareExamplePackage(t *testing.T) *packages_model.Package {
 	require.NoError(t, unittest.PrepareTestDatabase())