Add windows support for file.patch by using "git apply"

[poliva83]

Description of Issue/Question

file.patch state is very useful for Linux to apply a "better GNU patch". But could not get it working for windows because of the underlying execution file.patch function requiring that "patch" executable is installed.

https://github.com/saltstack/salt/blob/develop/salt/modules/file.py#L2718

There is a "Patch for Windows" executable (http://gnuwin32.sourceforge.net/packages/patch.htm) but it seems pretty old and unlikely to support newer windows versions. Thinking that file.patch could leverage "git apply" to apply a "better GNU patch" for windows (if git is installed). The --unsafe-paths option could be used to patch files outside the git working area.

--unsafe-paths
By default, a patch that affects outside the working area (either a Git controlled working tree, or the current working directory when "git apply" is used as a replacement of GNU patch) is rejected as a mistake (or a mischief).

When git apply is used as a "better GNU patch", the user can pass the --unsafe-paths option to override this safety check. This option has no effect when --index or --cached is in use.

If file.patch is not correct place for this then I'd at least like to see "git apply" be functionality added under git execution modules (https://docs.saltstack.com/en/latest/ref/modules/all/salt.modules.git.html).

Relevant link:
https://stackoverflow.com/questions/19611/how-to-patch-on-windows

[garethgreenaway]

@poliva83 Thanks for the report. Approving for a future feature addition.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

If this issue is closed prematurely, please leave a comment and we will gladly reopen the issue.

[poliva83]

I'd still like to see this feature implemented as there isn't great way to patch using salt in windows.

[stale]

Thank you for updating this issue. It is no longer marked as stale.

[max-arnold]

To see if it is possible to quickly fix the file.patch state to work on Windows, I did the following experiment:

1. Grabbed patch.exe and msys-2.0.dll from Git for Windows Portable: https://git-scm.com/download/win
2. Put both files into C:\Windows
3. Fixed the salt/modules/win_file.py module (added import, global and _namespaced_function)

sudo salt win10 state.apply patches.p1
win10:
----------
          ID: C:/1.txt
    Function: file.patch
      Result: True
     Comment: Patch successfully applied
     Started: 00:42:00.462963
    Duration: 187.52 ms
     Changes:
              ----------
              pid:
                  6800
              retcode:
                  0
              stderr:
              stdout:
                  patching file C:/1.txt

Summary for win10
------------
Succeeded: 1 (changed=1)
Failed:    0
------------
Total states run:     1
Total run time: 187.520 ms

However, on the second run it failed:

win10:
----------
          ID: C:/1.txt
    Function: file.patch
      Result: False
     Comment: Patch would not apply cleanly, no changes made. Results of dry-run are below. Run state again using the reject_file option to save rejects to a persistent file.

                            ----------
                            pid:
                                6956
                            retcode:
                                1
                            stderr:
                            stdout:
                                patching file 'C:\Users\user\AppData\Local\Temp\__salt.tmp.hgojw3am' (read from C:/1.txt)
                                Reversed (or previously applied) patch detected!  Skipping patch.
                                1 out of 1 hunk ignored -- saving rejects to file 'C:\Users\user\AppData\Local\Temp\__salt.tmp.muf48dv7'
     Started: 00:42:03.650579
    Duration: 171.764 ms
     Changes:

Summary for win10
------------
Succeeded: 0
Failed:    1
------------
Total states run:     1
Total run time: 171.764 ms

So, it kinda works, but I do not have the energy to fix it properly

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

If this issue is closed prematurely, please leave a comment and we will gladly reopen the issue.

[max-arnold]

Bump

[stale]

Thank you for updating this issue. It is no longer marked as stale.