fix: return error from Run() when ContinueOnError files fail

When --continue-on-error was set and one or more files failed to
process, Run() logged each failure but returned nil, making it
impossible for callers or CI systems to detect partial failures.

Track whether any file failed with a hasErrors flag and return a
descriptive error after all files have been attempted.

Update TestContinueOnError to reflect the corrected behaviour: the
test now asserts that an error IS returned (partial failure is
surfaced) while still verifying that all files in the batch are
attempted (not just the first one).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mark.go

@@ -102,6 +102,7 @@ func Run(config Config) error {
 		}
 	}
 
+	var hasErrors bool
 	for _, file := range files {
 		log.Infof(nil, "processing %s", file)
 
@@ -109,6 +110,7 @@ func Run(config Config) error {
 		if err != nil {
 			if config.ContinueOnError {
 				log.Errorf(err, "processing %s", file)
+				hasErrors = true
 				continue
 			}
 			return err
@@ -122,6 +124,10 @@ func Run(config Config) error {
 		}
 	}
 
+	if hasErrors {
+		return fmt.Errorf("one or more files failed to process")
+	}
+
 	return nil
 }
 
@@ -300,6 +306,9 @@ func ProcessFile(file string, api *confluence.API, config Config) (*confluence.P
 		if err != nil {
 			return nil, fmt.Errorf("unable to retrieve page by id: %w", err)
 		}
+		if pg == nil {
+			return nil, fmt.Errorf("page with id %q not found", config.PageID)
+		}
 		target = pg
 	}
 

markdown/markdown_test.go

@@ -181,5 +181,8 @@ func TestContinueOnError(t *testing.T) {
 	}
 
 	err := cmd.Run(context.TODO(), argList)
-	assert.NoError(t, err, "App should run without errors when continue-on-error is enabled")
+	// --continue-on-error processes all files even when some fail, but still
+	// returns an error to allow callers/CI to detect partial failures.
+	assert.Error(t, err, "App should report partial failure when continue-on-error is enabled and some files fail")
+	assert.ErrorContains(t, err, "one or more files failed to process")
 }