Remove ignored files from git tree

ci/README.md

@@ -349,6 +349,12 @@ This was deemed to be error prone and not worth the effort.
 
 ## `fix_gitignore.sh`
 
-This script makes sure that git ignores the sql files and expected output files
-that are generated from `.source` template files. If you created or deleted a
-`.source` file in a commit, git ignore rules should be updated.
+This script checks and fixes issues with `.gitignore` rules:
+
+1. Makes sure git ignores the `.sql` files and expected output files that are generated
+   from `.source` template files. If you created or deleted a `.source` file in a commit,
+   git ignore rules should be updated to reflect this change.
+
+2. Makes sure we do not commit any generated files that should be ignored. If there is an
+   ignored file in the git tree, the user is expected to review the files that are removed
+   from the git tree and commit them.

ci/fix_gitignore.sh

@@ -18,3 +18,17 @@ ls -1 src/test/regress/input | sed -E "s#(.*)\.source#/\1.sql#" > src/test/regre
 
 # e.g. multi_copy.source -> /multi_copy.out
 ls -1 src/test/regress/output | sed -E "s#(.*)\.source#/\1.out#" > src/test/regress/expected/.gitignore
+
+# Remove all the ignored files from git tree, and error out
+# find all ignored files in git tree, and use quotation marks to prevent word splitting on filenames with spaces in them
+ignored_lines_in_git_tree=$(git ls-files --ignored --exclude-standard | sed 's/.*/"&"/')
+
+if [[ -n $ignored_lines_in_git_tree ]]
+then
+    echo "Ignored files should not be in git tree!"
+    echo "${ignored_lines_in_git_tree}"
+
+    echo "Removing these files from git tree, please review and commit"
+    echo "$ignored_lines_in_git_tree" | xargs git rm -r --cached
+    exit 1
+fi