Fix file.append

[twangboy]

What does this PR do?

Fixes problem with extra newline characters in the file and the state return.

What issues does this PR fix or reference?

https://github.com/saltstack/zh/issues/783

Previous Behavior

Previously the salt state was iterating through each line in the source file and calling file.append. File.append checks for a newline character at the end of the file and adds one if it's missing. So there was a newline character being added on every line.

New Behavior

The salt state now sends a list of lines to be added to the file.append function.

Tests written?

Tested on Windows and Ubuntu
No

[cachedout]

This concerns me.

The first thing that's happening here is that a file.append state that currently returns with no changes in 2015.8 will rewrite the entire file. I am not inclined to introduce a change like that into a point release.

I'm a little confused by your description as well. What I was seeing when testing this was that in the current incarnation of 2015.8, only an additional line was being added which is what I would expect. However, your PR seems to modify every single line in the file. Example:

              diff:
                  --- 

                  +++ 

                  @@ -1,2 +1,3 @@

                  -The quick brown fox

                  -jumped over

                  +The quick brown fox
                  +jumped over
                  +The fence

This is not at all the behavior that I would expect from file.append. For reference, here's the current behavior:

              diff:
                  --- 
                  +++ 
                  @@ -1,2 +1,3 @@
                   The quick brown fox
                   jumped over
                  +The fence

I am going to cc: @thatch45 and @terminalmage here for additional review.

[thatch45]

Do we need the len() here?

[twangboy]

The len() determines if there were any lines appended to the file.

[thatch45]

right, but an empty list evaluates to False, and a list with stuff evaluates to True, making the len unnecessary:
https://docs.python.org/2/library/stdtypes.html#truth-value-testing

[twangboy]

I'm a dufus.....

[thatch45]

Looking at this, I wonder what we need the state changes for? I am just not following that.

[twangboy]

@cachedout @thatch45 I think @jfindlay explained the problem pretty well in https://gist.github.com/jfindlay/45fb2de7b5970ef773033013632a36d6

I will do some more testing

[twangboy]

@cachedout I believe your original file was missing a newline code after jumped over. file.append will add a newline code at the end of the file if it's missing.

[cachedout]

@twangboy The point is that The quick brown fox should not have been modified.

[twangboy]

@cachedout 'The quick brown fox' was not modified.... It's the diff comparison that thinks it was.... I submitted a fix. When it read the file before the append it was reading the line endings. After the append it was not. So, the compare showed that the line was changed.

[twangboy]

Rebased