Upgrade pip in gitlab ci without using get-pip.py

See merge request pycqa/flake8!411

config: Determine path to user configuration immediately

See merge request pycqa/flake8!409

Preemptively determine the path of the user configuration file during
the construction of the `ConfigFileFinder` object.  The user
configuration path will always be the same, regardless of when it gets
obtained by a run of `flake8`.

This isolates the logic of determining the user configuration path into
a static helper method to be called to set the `.user_config_file`
attribute.  The helper method leverages `utils.is_windows()`, instead of
reimplementing the check, and decomposes clearly the directory name and
the base name to construct the path with a single `return` path.
Additionally, this avoids reconstructing the path on demand of obtaining
the user configuration file path.

config: Remove checks for configs being previously parsed

See merge request pycqa/flake8!408

Remove the checks to see if a configuration file has already been seen
and parsed.  These checks aren't necessary because the entire run of
`flake8` calls these methods *only* once per configuration provided.

Ensure that a not-found file produces an error

Closes #600

See merge request pycqa/flake8!404

document that contents may appear before/after a noqa comment

Closes #528

See merge request pycqa/flake8!407

split lines the same when read from stdin

Closes #270

See merge request pycqa/flake8!406

Fix the type= warning to contain the option name

See merge request pycqa/flake8!405

- this restores a flake8 2.x behaviour that was lost in the refactor

Some typo fixes in git hooks docs

See merge request pycqa/flake8!403

config: Make ConfigFileFinder 'extra_config_files' parameter optional

See merge request pycqa/flake8!402

This simplifies the number of required parameters needed for the
`ConfigFileFinder` object throughout the various tests.

Determine config file override from the ConfigFileFinder object

See merge request pycqa/flake8!401

Now that `ConfigFileFinder.config_file` attribute is used everywhere and
is constructed from the `--config` CLI option, the now unused
`cli_config` parameters can be safely removed.

Now that the `ConfigFileFinder` has the `.config_file` attribute, switch
the relevant code paths to utilize this public attribute.

Tests have been updated to either construct `ConfigFileFinder` or mock
the object appropriately.

The `--config` flag is passed into `MergedConfigParser.parse()` and the
module-level function `config.get_local_plugins()`.  Since both of these
places utilize the `ConfigFileFinder` object and the configuration file
override pertains to how configuration behaves, this incremental change
directly associates the `ConfigFileFinder` and the configuration file
override.

config: Remove ConfigFileFinder 'parent' and 'tail' attributes

See merge request pycqa/flake8!400

application: Remove stale docstring param for `.find_plugins()`

See merge request pycqa/flake8!399

These attributes are only needed within the
`.generate_possible_local_files()` method.  Therefore, just obtain the
current working directory at the beginning of the method and reduce the
lifetime state of the `ConfigFileFinder` object.

`os.getcwd()` returns an absolute path; thus, the patched paths should
be absolute as well.

This is an incremental change towards removing the `ConfigFileFinder`
attributes `.parent` and `.tail` to be localized to
`.generate_possible_local_files()`.  Without this, the tests fail when
moving the patching because `os.path.abspath()` calls `os.getcwd()`,
expecting `os.getcwd()` to be an absolute path.

The 'ignore_config_files' parameter was accidentally not removed in
c918e724.

Determine config isolation from the ConfigFileFinder object

See merge request pycqa/flake8!398

Now that `ConfigFileFinder.ignore_config_files` attribute is used
everywhere and is constructed from the `--isolated` CLI option, the now
unused `isolated` parameters can be safely removed.

Now that the `ConfigFileFinder` has the `.ignore_config_files`
attribute, switch the relevant code paths to utilize this public
attribute.

Tests have been updated to either construct `ConfigFileFinder` or mock
the object appropriately.

The `--isolated` flag is passed into `MergedConfigParser.parse()` and
the module-level function `config.get_local_plugins()`.  Since both of
these places utilize the `ConfigFileFinder` object and isolation
pertains to how the `ConfigFileFinder` should behave with respect to
isolation, this incremental change more directly associates the
`ConfigFileFinder` and configuration file isolate.

config: Change ConfigFileFinder._read_config() to accept variadic args

See merge request pycqa/flake8!397

This simplifies `._read_config()` by removing a conditional branch in
the situation where it is called with one file to process.  Now the
contract accepts any number of arguments of the same type.

Where callers invoke `._read_config()` with a `Sequence`, the call site
has been changed to unpack arguments (i.e., `*`).

The tests in `test_merged_config_parser.py` needed to return a string
for the user configuration path instead of an empty list since
`ConfigFileFinder.user_config_file()` returns a string.

aggregator: Forward  --config and --isolated options during aggregation

Closes #605

See merge request pycqa/flake8!395

Prevent regressions by adding integration tests to ensure that these
options are passed through to `aggregator.aggregate_options()`.

This fixes a regression introduced in !346 to ensure that `--config` and
`--isolated` are recognized in `aggregate_options()`.

The regression manifested because `aggregate_options()` was relying on
re-parsing `argv` to obtain the option values.  However, !346 changed
the preliminary parsing logic to only parse and "eat" what is necessary
and forward along the options needed before all the configuration was
loaded.  This code path was overlooked because the tests in
`test_aggregator()` were passing but the call from the `Application`
object would never have these options in the remaining `argv` list to be
passed long.

application: Inline creation of config.ConfigFileFinder

See merge request pycqa/flake8!393

Simplify the initialization code path by invoking
`config.ConfigFileFinder` directly instead of the extra hop by calling
the static class-level `Application.make_config_finder()` method.

`--disable-noqa` does not override `# flake8: noqa`

Closes #590

See merge request pycqa/flake8!380