Fix verify workflow (#167)

This fixes the DB migration check in the verify workflow to allow reverting migration files.

bot/internal/bot/verify.go

@@ -63,6 +63,11 @@ func (b *Bot) verifyDBMigration(ctx context.Context, pathPrefix string) error {
 		return nil
 	}
 
+	// don't evaluate removed files
+	prFiles = filterSlice(prFiles, func(f github.PullRequestFile) bool {
+		return f.Status != "removed"
+	})
+
 	// parse PR migration file ids
 	// 202301031500_subscription-alter.up.sql => 202301031500
 	prIDs, err := parseMigrationFileIDs(pathPrefix, pullRequestFileNames(prFiles))
@@ -176,3 +181,15 @@ func pullRequestFileNames(files []github.PullRequestFile) []string {
 	}
 	return names
 }
+
+// filterSlice filters a slice returning a slice of the original items
+// excluding those itens where filterfunc returns false.
+func filterSlice[T any](ts []T, filterfunc func(T) bool) []T {
+	p := make([]T, 0, len(ts))
+	for i := range ts {
+		if filterfunc(ts[i]) {
+			p = append(p, ts[i])
+		}
+	}
+	return p
+}

bot/internal/bot/verify_test.go

@@ -96,6 +96,8 @@ func TestParseMigrationFileIDs(t *testing.T) {
 }
 
 func TestVerifyCloudDBMigration(t *testing.T) {
+	const defaultStatus = "added"
+
 	// load fake github with noop data
 	fgh := &fakeGithub{ref: github.Reference{Name: "foo", SHA: "abc"}}
 	fgh.files = []github.PullRequestFile{{Name: "foo.go"}, {Name: "pkg/lib/foo.go"}}
@@ -113,6 +115,7 @@ func TestVerifyCloudDBMigration(t *testing.T) {
 	cases := []struct {
 		prFiles     []string
 		branchFiles []string
+		status      string
 		expectErr   bool
 	}{
 		{}, // 0    no migration files in branch or pr
@@ -145,11 +148,26 @@ func TestVerifyCloudDBMigration(t *testing.T) {
 			},
 			expectErr: true,
 		},
+		{ // 5 OK   filter removed files
+			status: "removed",
+			prFiles: []string{
+				"db/202301031501_fake.up.sql",
+			},
+			branchFiles: []string{
+				"db/202301031501_exists.up.sql",
+			},
+		},
 	}
 	fghBaseline := *fgh
 	for i, test := range cases {
+		if test.status == "" {
+			test.status = defaultStatus
+		}
 		for _, f := range test.prFiles {
-			fgh.files = append(fgh.files, github.PullRequestFile{Name: f})
+			fgh.files = append(fgh.files, github.PullRequestFile{
+				Name:   f,
+				Status: test.status,
+			})
 		}
 		fgh.commitFiles = append(fgh.commitFiles, test.branchFiles...)
 

bot/internal/github/github.go

@@ -250,6 +250,8 @@ type PullRequestFile struct {
 	Additions int
 	// Deletions is the number of lines removed from the file
 	Deletions int
+	// Status is either added, removed, modified, renamed, copied, changed, unchanged
+	Status string
 }
 
 // PullRequestFiles is a list of pull request files.
@@ -411,6 +413,7 @@ func (c *Client) ListFiles(ctx context.Context, organization string, repository
 				Name:      file.GetFilename(),
 				Additions: file.GetAdditions(),
 				Deletions: file.GetDeletions(),
+				Status:    file.GetStatus(),
 			})
 		}