hackorum-patch: improve base commit lookup logic

Currently we simply looked at the first 50 commits, which wasn't able to
properly find the parent for old commits.

We also can't rely on the "Date" field in the patches, because with
rebases/changes, it might be significantly before the actual submission
date of the latest patch version.

To properly find earlier bases without going through a long list of
commits, this change adds a new metadata file containing the submission
date on the mailing list, which should be a better start time for
lookups.

Author: dutow

app/controllers/topics_controller.rb

@@ -147,12 +147,29 @@ def latest_patchset
     patches = latest_message.attachments.select(&:patch?).sort_by(&:file_name)
     return head :not_found if patches.empty?
 
+    # Calculate attachment number (1-based index among all messages with attachments)
+    messages_with_attachments = @topic.messages
+                                      .where(id: Attachment.where(message_id: @topic.messages.select(:id))
+                                                           .select(:message_id))
+                                      .order(created_at: :asc)
+    attachment_number = messages_with_attachments.index { |msg| msg.id == latest_message.id }.to_i + 1
+
     require 'zlib'
     require 'rubygems/package'
 
     tar_gz_data = StringIO.new
     Zlib::GzipWriter.wrap(tar_gz_data) do |gz|
       Gem::Package::TarWriter.new(gz) do |tar|
+        # Add metadata file first
+        metadata = {
+          attachment_number: attachment_number,
+          topic_id: @topic.id,
+          submission_date: latest_message.created_at.iso8601
+        }.to_json
+        tar.add_file_simple('hackorum.json', 0644, metadata.bytesize) do |io|
+          io.write(metadata)
+        end
+
         patches.each do |patch|
           content = patch.decoded_body_utf8
           tar.add_file_simple(patch.file_name, 0644, content.bytesize) do |io|

public/scripts/hackorum-patch

@@ -23,6 +23,7 @@ class HackorumPatch
     @local_archive = nil
     @using_local_file = false
     @using_diff_mode = false
+    @metadata = nil
 
     parse_options!(argv)
 
@@ -355,6 +356,11 @@ class HackorumPatch
       Gem::Package::TarReader.new(gz) do |tar|
         tar.each do |entry|
           next unless entry.file?
+          if entry.full_name == 'hackorum.json'
+            @metadata = JSON.parse(entry.read)
+            verbose_log "  Parsed metadata: submission_date=#{@metadata['submission_date']}"
+            next
+          end
           dest = File.join(@temp_dir, entry.full_name)
           File.write(dest, entry.read)
           puts "  Extracted: #{entry.full_name}"
@@ -376,6 +382,11 @@ class HackorumPatch
         Gem::Package::TarReader.new(gz) do |tar|
           tar.each do |entry|
             next unless entry.file?
+            if entry.full_name == 'hackorum.json'
+              @metadata = JSON.parse(entry.read)
+              verbose_log "  Parsed metadata: submission_date=#{@metadata['submission_date']}"
+              next
+            end
             dest = File.join(@temp_dir, entry.full_name)
             File.write(dest, entry.read)
             puts "  Extracted: #{entry.full_name}"
@@ -503,7 +514,16 @@ class HackorumPatch
     # Find commits on the default branch that touched these files
     paths = file_info.keys.map { |p| Shellwords.escape(p) }.join(" ")
     verbose_log "  Searching commits that touched: #{file_info.keys.join(', ')}"
-    commits = `git log #{default_branch} --pretty=format:%H -n 50 -- #{paths} 2>/dev/null`.strip.split("\n")
+
+    # Use submission date from metadata to constrain search
+    until_flag = ""
+    if @metadata && @metadata['submission_date']
+      submission_date = @metadata['submission_date']
+      verbose_log "  Using submission date constraint: --until=#{submission_date}"
+      until_flag = "--until=#{Shellwords.escape(submission_date)}"
+    end
+
+    commits = `git log #{default_branch} --pretty=format:%H #{until_flag} -n 200 -- #{paths} 2>/dev/null`.strip.split("\n")
     verbose_log "  Found #{commits.size} candidate commits to check"
 
     commits.each_with_index do |commit, idx|

public/scripts/hackorum-patch.changelog.json

@@ -5,6 +5,7 @@
       "version": "1.2.0",
       "date": "2026-02-04",
       "changes": [
+        "Improved base commit detection using submission date from archive metadata",
         "Added --verbose option for detailed base commit detection debugging"
       ]
     },