Change problem_on_unmodified_line default to report

When attempting to commit a file with hook warnings/errors on lines you
didn't modify, the previous default had Overcommit simply display these
problems as warnings.

However, in some situations this would lead to problems that were
introduced by a commit to still be treated as a warning. For example,
the `Rubocop` `MethodLength` cop reports an error on the method
definition line, but you typically add lines after that line so you may
only get a warning from Overcommit instead of an error.

Change the default to `report` will prevent these sorts of errors from
sneaking in, and results in Overcommit's default `PreCommit`
configuration acting more like its `RunAll` context, where all lines are
considered.

Users will still be able to switch back to `warn` as they desire, even
enabling it wholesale for all pre-commit hooks by setting it in the
`ALL` hook.

Author: sds

CHANGELOG.md

@@ -54,6 +54,7 @@
 * Update `childprocess` dependency to minimum 0.5.6
 * Restore file modification times of unstaged files in addition to staged files
   in pre-commit hook runs
+* Change default value for `problem_on_unmodified_line` from `warn` to `report`
 
 ## 0.23.0
 

README.md

@@ -173,7 +173,7 @@ Option                                  | Description
 `requires_files`                        | If `true`, this hook runs only if files that are applicable to it have been modified. See `include` and `exclude` for how to specify applicable files.
 `include`                               | File paths or glob patterns of files that apply to this hook. The hook will only run on the applicable files when they have been modified. Note that the concept of modified varies for different types of hooks. By default, `include` matches every file until you specify a list of patterns.
 `exclude`                               | File paths or glob patterns of files that do not apply to this hook. This is used to exclude any files that would have been matched by `include`.
-`problem_on_unmodified_line`            | How to treat errors reported on lines that weren't modified during the action captured by this hook (e.g. for pre-commit hooks, warnings/errors reported on lines that were not staged with `git add` are may not be warnings/errors you care about). Valid values are `report`: report errors/warnings as-is regardless of line location; `warn`: report errors as warnings if they are on lines you didn't modify; and `ignore`: don't display errors/warnings at all if they are on lines you didn't modify (`ignore` is _not_ recommended).
+`problem_on_unmodified_line`            | How to treat errors reported on lines that weren't modified during the action captured by this hook (e.g. for pre-commit hooks, warnings/errors reported on lines that were not staged with `git add` are may not be warnings/errors you care about). Valid values are `report`: report errors/warnings as-is regardless of line location (default); `warn`: report errors as warnings if they are on lines you didn't modify; and `ignore`: don't display errors/warnings at all if they are on lines you didn't modify (`ignore` is _not_ recommended).
 `on_fail`                               | Change the status of a failed hook to `warn` or `pass`. This allows you to treat failures as warnings or potentially ignore them entirely, but you should use caution when doing so as you might be hiding important information.
 `on_warn`                               | Simliar to `on_fail`, change the status of a hook that returns a warning status to either `pass` (you wish to silence warnings entirely) or `fail` (you wish to treat all warnings as errors).
 `required_executable`                   | Name of an executable that must exist in the `PATH` in order for the hook to run

config/default.yml

@@ -66,7 +66,7 @@ CommitMsg:
 # created.
 PreCommit:
   ALL:
-    problem_on_unmodified_line: warn
+    problem_on_unmodified_line: report
     requires_files: true
     required: false
     quiet: false