############################################################################

# Copyright (C) Internet Systems Consortium, Inc. ("ISC")

#

# This Source Code Form is subject to the terms of the Mozilla Public

# License, v. 2.0. If a copy of the MPL was not distributed with this

# file, you can obtain one at https://mozilla.org/MPL/2.0/.

#

# See the COPYRIGHT file distributed with this work for additional

# information regarding copyright ownership.

############################################################################

import re

# Helper functions and variables

def added_lines(target_branch, paths):

    import subprocess

    subprocess.check_output(['/usr/bin/git', 'fetch', '--depth', '1', 'origin',

                             target_branch])

    diff = subprocess.check_output(['/usr/bin/git', 'diff', 'FETCH_HEAD..',

                                    '--'] + paths)

    added_lines = []

    for line in diff.splitlines():

        if line.startswith(b'+') and not line.startswith(b'+++'):

            added_lines.append(line)

    return added_lines

issue_or_mr_id_regex = re.compile(br'\[(GL [#!]|RT #)[0-9]+\]')

release_notes_regex = re.compile(r'doc/(arm|notes)/notes-.*\.(rst|xml)')

modified_files = danger.git.modified_files

mr_labels = danger.gitlab.mr.labels

target_branch = danger.gitlab.mr.target_branch

###############################################################################

# COMMIT MESSAGES

###############################################################################

#

# - FAIL if any of the following is true for any commit on the MR branch:

#

#     * The subject line starts with "fixup!" or "Apply suggestion".

#

#     * There is no empty line between the subject line and the log message.

#

# - WARN if any of the following is true for any commit on the MR branch:

#

#     * The length of the subject line exceeds 72 characters.

#

#     * There is no log message present (i.e. commit only has a subject) and the

#       subject line does not contain any of the following strings: "fixup! ",

#       " CHANGES ", " release note".

#

#     * Any line of the log message is longer than 72 characters.  This rule is

#       not evaluated for lines starting with four spaces, which allows long

#       lines to be included in the commit log message by prefixing them with

#       four spaces (useful for pasting compiler warnings, static analyzer

#       messages, log lines, etc.)

for commit in danger.git.commits:

    message_lines = commit.message.splitlines()

    subject = message_lines[0]

    if subject.startswith('fixup!') or subject.startswith('Apply suggestion'):

        fail('Fixup commits are still present in this merge request. '

             'Please squash them before merging.')

    if len(subject) > 72:

        warn(

            f'Subject line for commit {commit.sha} is too long: '

            f'```{subject}``` ({len(subject)} > 72 characters).'

        )

    if len(message_lines) > 1 and message_lines[1]:

        fail(f'No empty line after subject for commit {commit.sha}.')

    if (len(message_lines) < 3 and

            'fixup! ' not in subject and

            ' CHANGES ' not in subject and

            ' release note' not in subject):

        warn(f'Please write a log message for commit {commit.sha}.')

    for line in message_lines[2:]:

        if len(line) > 72 and not line.startswith('    '):

            warn(

                f'Line too long in log message for commit {commit.sha}: '

                f'```{line}``` ({len(line)} > 72 characters).'

            )

###############################################################################

# MILESTONE

###############################################################################

#

# FAIL if the merge request is not assigned to any milestone.

if not danger.gitlab.mr.milestone:

    fail('Please assign this merge request to a milestone.')

###############################################################################

# VERSION LABELS

###############################################################################

#

# FAIL if any of the following is true for the merge request:

#

# * The "Backport" label is set and the number of version labels set is

#   different than 1.  (For backports, the version label is used for indicating

#   its target branch.  This is a rather ugly attempt to address a UI

#   deficiency - the target branch for each MR is not visible on milestone

#   dashboards.)

#

# * Neither the "Backport" label nor any version label is set.  (If the merge

#   request is not a backport, version labels are used for indicating

#   backporting preferences.)

backport_label_set = 'Backport' in mr_labels

version_labels = [l for l in mr_labels if l.startswith('v9.')]

if backport_label_set and len(version_labels) != 1:

    fail('The *Backport* label is set for this merge request. '

         'Please also set exactly one version label (*v9.x*).')

if not backport_label_set and not version_labels:

    fail('If this merge request is a backport, set the *Backport* label and '

         'a single version label (*v9.x*) indicating the target branch. '

         'If not, set version labels for all targeted backport branches.')

###############################################################################

# OTHER LABELS

###############################################################################

#

# WARN if any of the following is true for the merge request:

#

# * The "Review" label is not set.  (It may be intentional, but rarely is.)

#

# * The "Review" label is set, but the "LGTM" label is not set.  (This aims to

#   remind developers about the need to set the latter on merge requests which

#   passed review.)

if 'Review' not in mr_labels:

    warn('This merge request does not have the *Review* label set. '

         'Please set it if you would like the merge request to be reviewed.')

elif 'LGTM (Merge OK)' not in mr_labels:

    warn('This merge request is currently in review. '

         'It should not be merged until it is marked with the *LGTM* label.')

###############################################################################

# 'CHANGES' FILE

###############################################################################

#

# FAIL if any of the following is true:

#

# * The merge request does not update the CHANGES file, but it does not have

#   the "No CHANGES" label set.  (This attempts to ensure that the author of

#   the MR did not forget about adding a CHANGES entry.)

#

# * The merge request updates the CHANGES file, but it has the "No CHANGES"

#   label set.  (This attempts to ensure the the "No CHANGES" label is used in

#   a sane way.)

#

# * The merge request adds a new CHANGES entry that does not contain any

#   GitLab/RT issue/MR identifiers.

changes_modified = 'CHANGES' in modified_files

no_changes_label_set = 'No CHANGES' in mr_labels

if not changes_modified and not no_changes_label_set:

    fail('This merge request does not modify `CHANGES`. '

         'Add a `CHANGES` entry or set the *No CHANGES* label.')

if changes_modified and no_changes_label_set:

    fail('This merge request modifies `CHANGES`. '

         'Revert `CHANGES` modifications or unset the *No Changes* label.')

changes_added_lines = added_lines(target_branch, ['CHANGES'])

identifiers_found = filter(issue_or_mr_id_regex.search, changes_added_lines)

if changes_added_lines and not any(identifiers_found):

    fail('No valid issue/MR identifiers found in added `CHANGES` entries.')

###############################################################################

# RELEASE NOTES

###############################################################################

#

# - FAIL if any of the following is true:

#

#     * The merge request does not update release notes and has the "Release

#       Notes" label set.  (This attempts to point out missing release notes.)

#

#     * The merge request updates release notes but does not have the "Release

#       Notes" label set.  (This ensures that merge requests updating release

#       notes can be easily found using the "Release Notes" label.)

#

# - WARN if this merge request updates release notes, but no GitLab/RT issue/MR

#   identifiers are found in the lines added to the release notes by this MR.

release_notes_regex = re.compile(r'doc/(arm|notes)/notes-.*\.(rst|xml)')

release_notes_changed = list(filter(release_notes_regex.match, modified_files))

release_notes_label_set = 'Release Notes' in mr_labels

if not release_notes_changed and release_notes_label_set:

    fail('This merge request has the *Release Notes* label set. '

         'Add a release note or unset the *Release Notes* label.')

if release_notes_changed and not release_notes_label_set:

    fail('This merge request modifies release notes. '

         'Revert release note modifications or set the *Release Notes* label.')

if release_notes_changed:

    notes_added_lines = added_lines(target_branch, release_notes_changed)

    identifiers_found = filter(issue_or_mr_id_regex.search, notes_added_lines)

    if notes_added_lines and not any(identifiers_found):

        warn('No valid issue/MR identifiers found in added release notes.')