Preparation for #865, which proposes adding a flag which outputs which
config options are used during formatting.
This PR should not make any difference to functionality. A lot of this
was search-and-replace.
Some areas worthy of review/discussion:
- The method for each config item returns a clone of the underlying
value. We can't simply return an immutable reference, as lots of
places in the code expect to be able to pass the returned value as
`bool` (not `&bool). It would be nice if the `bool` items could
return a copy, but the more complex types a borrowed reference... but
unfortunately, I couldn't get the macro to do this.
- A few places (mostly tests and `src/bin/rustfmt.rs`) were overriding
config items by modifying the fields of the `Config` struct directly.
They now use the existing `override_value()` method, which has been
modified to return a `Result` for use by `src/bin/rustfmt.rs`. This
benefits of this are that the complex `file_lines` and `write_mode`
strings are now parsed in one place (`Config.override_value`) instead
of multiple. The disadvantages are that it moves the compile-time
checks for config names to become run-time checks.
* Change required to prevent a trailing space at the end of a separate module being propagated
* Detect the start of the output file rather than the start of the input file when deciding whether to output preceding snippets - this stops unnecessary whitespace and blank lines from being inserted when spans and statements are output in an order other than that from the input file.
* Add code to prevent space from being added with the prefix snippet if a) the snippet is entirely horizontal whitespace, or b) the snippet contains whitespace followed by a newline. This prevents trailing spaces at the end of a line from being added.
* Tests for this issue
* Tidy up `match` statements
* Add test with blank lines between `use` statements
This commit tidies up handling of `write_mode` by setting it in the
config at the start, and removing the `write_mode` parameter threaded
throughout the formatting process.
Also from @marcusklaas:
Refactor code output functions
Specifically, `write_all_files` no longer returns a HashMap. It would sometimes
contain items, and sometimes be empty. When "fixed" newlines are required, this
must now be done with a separate call. The tests use this strategy and should now pass!
When block comments were rewritten to line comments they check if a new line needs to be added and adds one if needed. It only checked for '\n' however which would cause a newline to be added even if the comment was ended by "\r\n"
This means that we try formatting the last argument of a function call with block
indentation instead of visual indentation when it is a closure and its first line
fits on the same line as the first arguments.
