commit 5e57ebabba84c54de5a1a9da3d3db9687b9173ed
author Sutou Kouhei <kou@clear-code.com> Fri Dec 16 09:22:49 2022 +0900
committer Matt Topol <zotthewizard@gmail.com> Fri Dec 16 10:54:50 2022 -0500
tree 9eac0f80cd1d9018d8174b84a75c8779161ddcbd
parent ecfccddff6cce35327cd2f4a0ca889453f522c2a

GH-14986: [Release] Don't detect previous version on maint-X.Y.Z branch (#14987)

We can't detect it automatically because r/DESCRIPTION doesn't have the information.
* Closes: #14986

Authored-by: Sutou Kouhei <kou@clear-code.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>
(cherry picked from commit b03a8adf2bedb30d376747d06a245e86a61874bf)

dev/release/test-helper.rb

diff --git a/dev/release/test-helper.rb b/dev/release/test-helper.rb
index 33fa201..9a50817 100644
--- a/dev/release/test-helper.rb
+++ b/dev/release/test-helper.rb
@@ -109,7 +109,11 @@
     @next_so_version = compute_so_version(@next_version)
     r_description = top_dir + "r" + "DESCRIPTION"
     @previous_version = r_description.read[/^Version: (.+?)\.9000$/, 1]
-    @previous_compatible_version = @previous_version.split(".")[0, 2].join(".")
+    if @previous_version
+      @previous_compatible_version = @previous_version.split(".")[0, 2].join(".")
+    else
+      @previous_compatible_version = nil
+    end
   end
 
   def compute_so_version(version)