ci: Add gitlint to pipeline

This uses my personal preferences [1] to lint the project's history.

[1] https://github.com/Notgnoshi/dotfiles/tree/master/stowdir/.config/gitlint

.github/gitlint/body_max_line_length_with_exceptions.py

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+import re
+
+from gitlint.rules import BodyMaxLineLength
+
+
+class BodyMaxLineLengthWithExceptions(BodyMaxLineLength):
+    """Extend the existing body-max-line-length rule.
+
+    Allow narrow exceptions, specifically leading block quote-style
+    indent and footnote-style URLs, to the line length enforcement.
+    """
+
+    name = "body-max-line-length-with-exceptions"
+    id = "UC2"
+
+    def validate(self, line, commit):
+        # Allow block-quoted lines to exceed the line length limit.
+        if line.startswith(" " * 4):
+            return None
+
+        # Allow footnote lines to exceed the line length limit.
+        ret = re.match(r"^\[\d+\] ", line)
+        if ret is not None:
+            return None
+
+        return super().validate(line, commit)

.github/gitlint/gitlint.ini

@@ -0,0 +1,23 @@
+[general]
+ignore=body-is-missing,body-max-line-length
+
+ignore-merge-commits=false
+# If you're reverting a commit, the revert commit should darn well contain enough information about WHY
+ignore-revert-commits=false
+ignore-fixup-commits=false
+ignore-fixup-amend-commits=false
+ignore-squash-commits=false
+
+# This will be the default in the future, so enable now
+regex-style-search=true
+
+[title-must-not-contain-word]
+words=wip,fixup,fixups,squash,fixme,dropme,dontmerge,donotmerge
+
+# 72 should be the target, but don't fail until it's past 80.
+[body-max-line-length-with-exceptions]
+line-length=80
+
+# Not every commit needs a body. Some are simple enough just a title will do
+[body-min-length]
+min-length=0

.github/gitlint/title_imperative_mood.py

@@ -0,0 +1,321 @@
+from typing import List
+
+from gitlint.git import GitCommit
+from gitlint.rules import CommitMessageTitle, LineRule, RuleViolation
+
+# Word list from https://github.com/m1foley/fit-commit
+# Copyright (c) 2015 Mike Foley
+# License: MIT
+# Ref: fit_commit/validators/tense.rb
+WORD_SET = {
+    "adds",
+    "adding",
+    "added",
+    "allows",
+    "allowing",
+    "allowed",
+    "amends",
+    "amending",
+    "amended",
+    "bumps",
+    "bumping",
+    "bumped",
+    "calculates",
+    "calculating",
+    "calculated",
+    "changes",
+    "changing",
+    "changed",
+    "cleans",
+    "cleaning",
+    "cleaned",
+    "commits",
+    "committing",
+    "committed",
+    "corrects",
+    "correcting",
+    "corrected",
+    "creates",
+    "creating",
+    "created",
+    "darkens",
+    "darkening",
+    "darkened",
+    "disables",
+    "disabling",
+    "disabled",
+    "displays",
+    "displaying",
+    "displayed",
+    "documents",
+    "documenting",
+    "documented",
+    "drys",
+    "drying",
+    "dryed",
+    "ends",
+    "ending",
+    "ended",
+    "enforces",
+    "enforcing",
+    "enforced",
+    "enqueues",
+    "enqueuing",
+    "enqueued",
+    "extracts",
+    "extracting",
+    "extracted",
+    "finishes",
+    "finishing",
+    "finished",
+    "fixes",
+    "fixing",
+    "fixed",
+    "formats",
+    "formatting",
+    "formatted",
+    "guards",
+    "guarding",
+    "guarded",
+    "handles",
+    "handling",
+    "handled",
+    "hides",
+    "hiding",
+    "hid",
+    "increases",
+    "increasing",
+    "increased",
+    "ignores",
+    "ignoring",
+    "ignored",
+    "implements",
+    "implementing",
+    "implemented",
+    "improves",
+    "improving",
+    "improved",
+    "keeps",
+    "keeping",
+    "kept",
+    "kills",
+    "killing",
+    "killed",
+    "makes",
+    "making",
+    "made",
+    "merges",
+    "merging",
+    "merged",
+    "moves",
+    "moving",
+    "moved",
+    "permits",
+    "permitting",
+    "permitted",
+    "prevents",
+    "preventing",
+    "prevented",
+    "pushes",
+    "pushing",
+    "pushed",
+    "rebases",
+    "rebasing",
+    "rebased",
+    "refactors",
+    "refactoring",
+    "refactored",
+    "removes",
+    "removing",
+    "removed",
+    "renames",
+    "renaming",
+    "renamed",
+    "reorders",
+    "reordering",
+    "reordered",
+    "replaces",
+    "replacing",
+    "replaced",
+    "requires",
+    "requiring",
+    "required",
+    "restores",
+    "restoring",
+    "restored",
+    "sends",
+    "sending",
+    "sent",
+    "sets",
+    "setting",
+    "separates",
+    "separating",
+    "separated",
+    "shows",
+    "showing",
+    "showed",
+    "simplifies",
+    "simplifying",
+    "simplified",
+    "skips",
+    "skipping",
+    "skipped",
+    "sorts",
+    "sorting",
+    "speeds",
+    "speeding",
+    "sped",
+    "starts",
+    "starting",
+    "started",
+    "supports",
+    "supporting",
+    "supported",
+    "takes",
+    "taking",
+    "took",
+    "testing",
+    "tested",  # 'tests' excluded to reduce false negative
+    "truncates",
+    "truncating",
+    "truncated",
+    "updates",
+    "updating",
+    "updated",
+    "uses",
+    "using",
+    "used",
+}
+
+imperative_forms = [
+    "add",
+    "allow",
+    "amend",
+    "bump",
+    "calculate",
+    "change",
+    "clean",
+    "commit",
+    "correct",
+    "create",
+    "darken",
+    "disable",
+    "display",
+    "document",
+    "dry",
+    "end",
+    "enforce",
+    "enqueue",
+    "extract",
+    "finish",
+    "fix",
+    "format",
+    "guard",
+    "handle",
+    "hide",
+    "ignore",
+    "implement",
+    "improve",
+    "increase",
+    "keep",
+    "kill",
+    "make",
+    "merge",
+    "move",
+    "permit",
+    "prevent",
+    "push",
+    "rebase",
+    "refactor",
+    "remove",
+    "rename",
+    "reorder",
+    "replace",
+    "require",
+    "restore",
+    "send",
+    "separate",
+    "set",
+    "show",
+    "simplify",
+    "skip",
+    "sort",
+    "speed",
+    "start",
+    "support",
+    "take",
+    "test",
+    "truncate",
+    "update",
+    "use",
+]
+imperative_forms.sort()
+
+
+def head_binary_search(key: str, words: List[str]) -> str:
+    """Find the imperative mood version of `word` by looking at the first 3 characters."""
+    # Edge case: 'disable' and 'display' have the same 3 starting letters.
+    if key in ["displays", "displaying", "displayed"]:
+        return "display"
+
+    lower = 0
+    upper = len(words) - 1
+
+    while True:
+        if lower > upper:
+            # Should not happen
+            raise Exception(f"Cannot find imperative mood of {key}")
+
+        mid = (lower + upper) // 2
+        imperative_form = words[mid]
+
+        if key[:3] == imperative_form[:3]:
+            return imperative_form
+        if key < imperative_form:
+            upper = mid - 1
+        elif key > imperative_form:
+            lower = mid + 1
+
+
+class ImperativeMood(LineRule):
+    """A rule to enforce that the commit message title uses imperative mood.
+
+    This is done by checking if the first word is in `WORD_SET`, if so show the word in the correct
+    mood.
+    """
+
+    name = "title-imperative-mood"
+    id = "UC1"
+    target = CommitMessageTitle
+
+    error_msg = (
+        "The first word in commit title should be in imperative mood "
+        '("{word}" -> "{imperative}"): "{title}"'
+    )
+
+    def validate(self, line: str, commit: GitCommit) -> List[RuleViolation]:
+        """Validate the given commit message."""
+        violations = []
+
+        # Ignore the section tag (ie `<section tag>: <message body>.`)
+        words = line.split(": ", 1)[-1].split()
+
+        if not words:
+            return None
+
+        first_word = words[0].lower()
+
+        if first_word in WORD_SET:
+            imperative = head_binary_search(first_word, imperative_forms)
+            violation = RuleViolation(
+                self.id,
+                self.error_msg.format(
+                    word=first_word,
+                    imperative=imperative,
+                    title=commit.message.title,
+                ),
+            )
+
+            violations.append(violation)
+
+        return violations