Don't edit commit history with migrate from tempest tool

This commit changes the migrate_from_tempest tool to not mess around
with the commit history. The previous approach in the tool isn't
actually something that we can do. The commit history we had when the
repository was created is the canonical past for tempest-lib and we
can't migrate over any other tempest commits directly, this was a
mistake on my part.

Moving forward we'll just have to refer to the commit sha1s from the
tempest repo in the commit message. This script will now just copy the
specified files from tempest and generate a commit message with the
complete list of sha1s from the tempest history.

Change-Id: I7e2b2a0543d113961598b33d23985a1082fbba9a

1 files changed, 27 insertions, 16 deletions

diff --git a/tools/migrate_from_tempest.sh b/tools/migrate_from_tempest.sh
index 9e4f9e4..2bf02d1 100755
--- a/tools/migrate_from_tempest.sh
+++ b/tools/migrate_from_tempest.sh
@@ -1,16 +1,15 @@
 #!/bin/bash
 #
-# Use this script to move over a set of files from tempest master with commit
-# history into the tempest lib. You must only do this for files that haven't
-# been migrated over already.
-# 
+# Use this script to move over a set of files from tempest master into
+# tempest-lib with the commit history for the files in the commit message.
+# This should only be done for files that haven't been migrated over already.
 # To use:
 #  1. Create a new branch in the tempest-lib repo so not to destroy your current
 #     working branch
 #  2. Run the script from the repo dir and specify the file paths relative to
 #     the root tempest dir(only code and unit tests):
 #
-#   tools/migrate_from_tempest.sh tempest/
+#   tools/migrate_from_tempest.sh tempest/file.py tempest/sub_dir
 
 
 function usage {
@@ -62,7 +61,7 @@ for file in $files; do
          if git merge-base --is-ancestor $root $file_root; then
              fail=1
              break
-         elif !git merge-base --is-ancestor $file_root $root; then
+         elif ! git merge-base --is-ancestor $file_root $root; then
              new_roots="$new_roots $root"
          fi
      done
@@ -95,22 +94,34 @@ fi
 EOF
 )
 
+# Prune just the commits relevant to what is being migrated
 git filter-branch --index-filter "$pruner" --parent-filter "$set_roots" --commit-filter "$skip_empty" HEAD
 
-# Pull changes
-cd -
-git remote add tempest-migrate $tmpdir
-git pull tempest-migrate master
-git remote rm tempest-migrate
+SHA1_LIST=`git log --oneline`
 
+# Move files and commit
+cd -
+file_list=''
 for file in $files; do
     filename=`basename $file`
     if [ -n "$output_dir" ]; then
-        git mv $file "$output_dir/$filename"
+        dest_file="$output_dir/$filename"
+    else
+        dest_file="tempest_lib/$filename"
+    fi
+    cp -r "$tmpdir/$file" "$dest_file"
+    git add "$dest_file"
+    if [[ -z "$file_list" ]]; then
+        file_list="$filename"
     else
-        git mv $file "tempest_lib/$filename"
+        file_list="$file_list, $filename"
     fi
 done
-rm -r tempest
-git add .
-git commit -m "Moved files from previous merge as part of tempest migration"
+# Cleanup temporary tempest repo
+rm -rf $tmpdir
+
+# Generate a migration commit
+commit_message="Migrated $file_list from tempest"
+pre_list=$"This migrates the above files from tempest. This includes tempest commits:"
+post_list=$"to see the commit history for these files refer to the above sha1s in the tempest repository"
+git commit -m "$commit_message" -m "$pre_list" -m "$SHA1_LIST" -m "$post_list"