Address file.managed with contents_newline flag

[xeacott]

What does this PR do?

Address the issue of the file.managed state not using contents_newline correctly.

What issues does this PR fix or reference?

Issue #54177

Previous Behavior

            for part in validated_contents:
                for line in part.splitlines():
                    contents += line.rstrip('\n').rstrip('\r') + os.linesep
            if contents_newline and not contents.endswith(os.linesep):
                contents += os.linesep

Because of the for loop EOF would contain a platform-specific line-ending, even if the user set
contents_newline = False. According to the documentation, contents_newline should allow the user
to specify that they don't want the file to end with a newline.

New Behavior

Setting contents_newline = False will now determine if the last entry in the file should end with
a newline character

Tests written?

Yes

Commits signed with GPG?

Yes

[waynew]

Wouldn't it be appropriate to open this in rb mode instead? 🤔

[xeacott]

Hmm, you aren't wrong! I must have forgotten the b

[xeacott]

Actually no I believe it should remain as r. I thought about this and the PR was incorrectly named (definitely my fault) but opening the file in binary mode and then reading it will produce different results based on the platform, i.e. Window's will read the contents differently than a linux platform. So I decided to just open the file in r as it's more in-line with the change in logic itself. Does that make sense?

[DmitryKuzmenko]

Some logical error here. Probably correct one is:

if not line == part[-1]:

But it would be also wrong to compare the contents because the content could contains equal data, say

line
line
line

So you probably will want something like this:

lines = part.splitlines()
for num, line in enumerate(lines):
    if not num == len(lines) - 1

[dwoz]

@waynew @DmitryKuzmenko Are we good here?

[defanator]

@dwoz @DmitryKuzmenko which release will include this particular fix? TIA!

[defanator]

@xeacott what is the nearest planned salt release with this fix included? TIA!

[oeuftete]

@defanator This fix will be part of the upcoming Salt 3000 (Neon) release.