[Lldb-commits] [lldb] [lldb] Fix and re-enable TestUseSourceCache.py (PR #111237)

[Emre Kultursay via lldb-commits]

emrekultursay wrote:

OK, I figured the problem.  In the test, we call `os.removeFile()` which does not actually represent the real end-user use-case (which is to edit the file and save it). 

Empirically, on Windows 11, I can verify that when LLDB mmaps these large files, then:
 1. I can append to the file from Python (mode="a")
 2. I can delete the file from Python (what the current test is doing)
 3. I cannot delete the file from File Explorer => says lldb.exe is using the file
 4. I cannot overwrite the file from Python (mode="w")
 5. I cannot overwrite/save the file from Notepad++ 
 6. I can overwrite/save the file from vi.

I am guessing that there are different mechanisms for deleting/editing/saving, and different editors/tools use different approaches. 

To make the test more representative, I replaced the `removeFile()` method with the following

```
    def overwriteFile(self, src):
        """Write to file and return true iff file was successfully written."""
        try:
            f = open(src, "w") 
            f.writelines(["// hello world\n"])
            return True
        except Exception:
            return False












https://github.com/llvm/llvm-project/pull/111237