Fix file:copy to return error when target file exists without REPLACE_EXISTING

[DharshiBalasubramaniyam]

Purpose

Fixes ballerina-platform/ballerina-library#8316

Examples

With this implementation below code returns InvalidOperationError, if temp2.txt already exists.

public function main() returns error? {
    string sourcePath = "temp1.txt";
    string destPath = "temp2.txt";
    file:Error? copy = file:copy(sourcePath, destPath);
    if copy is file:Error {
        io:println(copy.message());
    }
    io:println("done");
}

Output for the above code:

error InvalidOperationError ("The target file already exists: temp2.txt")

Tests

I have added 4 tests to reflect the below scenarios.

1. testCopyFileToNonExistentFileReplaceFalse - file should be copied
2. testCopyFileToExistingFileReplaceFalse - return error
3. testCopyFileToExistingFileReplaceTrue - file replaced
4. testCopyFileToNonExistentFileReplaceTrue - file created

Checklist

• Linked to an issue
• Updated the changelog
• Added tests
• Updated the spec
• Checked native-image compatibility

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.32%. Comparing base (ad65395) to head (a8b03de).

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #577      +/-   ##
============================================
- Coverage     82.64%   82.32%   -0.32%     
  Complexity       91       91              
============================================
  Files            18       18              
  Lines           772      775       +3     
  Branches        164      164              
============================================
  Hits            638      638              
- Misses          115      118       +3     
  Partials         19       19              

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[DharshiBalasubramaniyam]

Hi @ThisaruGuruge, can you please review this pr?

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[DharshiBalasubramaniyam]

Hi, @ThisaruGuruge, @niveathika, Any update on this pr?