Merge pull request chapel-lang#16342 from ben-albrecht/workaround-tom…

…l-error

Work-around TOML bug in mason and add a future for bug

TOML module produces a seg fault when parsing a file containing only a comment on linux32 / valgrind configs.\

This was exposed when `mason search` started adding a cache file containing only a comment if a cache
file did not exist (chapel-lang#16223). 

In this PR, we work around this bug by creating an empty cache file instead.

Also:

- added the `cache.toml` to CLEANFILES to prevent previous runs from interfering with each other in local testing
- added a future for the TOML bug - to be debugged in the future.

[Reviewed by @ronawho]

test/library/packages/TOML/test/commentOnly.chpl

@@ -0,0 +1,11 @@
+use TOML;
+
+config const str: string = """# Comment""";
+
+proc main() {
+  var TomlData = parseToml(str);
+  writeln(TomlData);
+  delete TomlData;
+}
+
+

test/library/packages/TOML/test/commentOnly.future

@@ -0,0 +1,2 @@
+bug: TOML containing only comments produces memory errors (caught in valgrind)
+

test/mason/search/badFileName/CLEANFILES

@@ -0,0 +1 @@
+mason_home/mason-registry/Bricks/cache.toml

tools/mason/MasonSearch.chpl

@@ -169,8 +169,7 @@ proc rankResults(results: list(string), query: string): [] string {
 /* Creates an empty cache file if its not found in registry */
 proc touch(pathToReg: string) {
   const fileWriter = open(pathToReg, iomode.cw).writer();
-  const contents = "# This cache file was created automatically by mason search";
-  fileWriter.write(contents);
+  fileWriter.write("");
   fileWriter.close();
 }