From 8c7c758bed5585a4096d287f3aa275c095b8851a Mon Sep 17 00:00:00 2001
From: Linus Groh <mail@linusgroh.de>
Date: Mon, 16 Dec 2024 19:51:16 +0000
Subject: [PATCH] Meta: Ignore title length of revert commits

Even if a commit message title previously fit into the 72 character
limit it may go over that with 'Revert ""' added - asking the author to
tweak the commit message is not appropriate in that case.

Since additional context can be added to the commit message body the
usual length restriction applies to the remaining lines.

Also restructure the code to group checks based on the line number we're
currently looking at.
---
 Meta/lint-commit.sh | 57 +++++++++++++++++++++++++--------------------
 1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/Meta/lint-commit.sh b/Meta/lint-commit.sh
index 878e87c8a43a9d..a79139341a2372 100755
--- a/Meta/lint-commit.sh
+++ b/Meta/lint-commit.sh
@@ -30,36 +30,43 @@ while read -r line; do
   ((line_number += 1))
   line_length=${#line}
 
-  if [[ $line_number -eq 2 ]] && [[ $line_length -ne 0 ]]; then
-    error "Empty line between commit title and body is missing"
-  fi
+  if [[ $line_number -eq 1 ]]; then
+    merge_commit_pattern="^Merge branch"
+    if (echo "$line" | grep -E -q "$merge_commit_pattern"); then
+      error "Commit is a git merge commit, use the rebase command instead"
+    fi
 
-  merge_commit_pattern="^Merge branch"
-  if [[ $line_number -eq 1 ]] && (echo "$line" | grep -E -q "$merge_commit_pattern"); then
-    error "Commit is a git merge commit, use the rebase command instead"
-  fi
+    category_pattern='^(Revert "|\S+: )'
+    if (echo "$line" | grep -E -v -q "$category_pattern"); then
+      error "Missing category in commit title (if this is a fix up of a previous commit, it should be squashed)"
+    fi
 
-  category_pattern='^(Revert "|\S+: )'
-  if [[ $line_number -eq 1 ]] && (echo "$line" | grep -E -v -q "$category_pattern"); then
-    error "Missing category in commit title (if this is a fix up of a previous commit, it should be squashed)"
-  fi
+    revert_pattern='^Revert "'
+    if [[ $line_length -gt 72 ]] && (echo "$line" | grep -E -v -q "$revert_pattern"); then
+      error "Commit title is too long (maximum allowed is 72 characters)"
+    fi
 
-  title_case_pattern="^\S.*?: [A-Z0-9]"
-  if [[ $line_number -eq 1 ]] && (echo "$line" | grep -E -v -q "$title_case_pattern"); then
-    error "First word of commit after the subsystem is not capitalized"
-  fi
+    title_case_pattern="^\S.*?: [A-Z0-9]"
+    if (echo "$line" | grep -E -v -q "$title_case_pattern"); then
+      error "First word of commit after the subsystem is not capitalized"
+    fi
 
-  if [[ $line_number -eq 1 ]] && [[ "$line" =~ \.$ ]]; then
-    error "Commit title ends in a period"
-  fi
-
-  url_pattern="([a-z]+:\/\/)?(([a-zA-Z0-9_]|-)+\.)+[a-z]{2,}(:\d+)?([a-zA-Z_0-9@:%\+.~\?&\/=]|-)+"
-  if [[ $line_length -gt 72 ]] && (echo "$line" | grep -E -v -q "$url_pattern"); then
-    error "Commit message lines are too long (maximum allowed is 72 characters)"
-  fi
+    if [[ "$line" =~ \.$ ]]; then
+      error "Commit title ends in a period"
+    fi
+  elif [[ $line_number -eq 2 ]]; then
+    if [[ $line_length -ne 0 ]]; then
+      error "Empty line between commit title and body is missing"
+    fi
+  else
+    url_pattern="([a-z]+:\/\/)?(([a-zA-Z0-9_]|-)+\.)+[a-z]{2,}(:\d+)?([a-zA-Z_0-9@:%\+.~\?&\/=]|-)+"
+    if [[ $line_length -gt 72 ]] && (echo "$line" | grep -E -v -q "$url_pattern"); then
+      error "Commit message lines are too long (maximum allowed is 72 characters)"
+    fi
 
-  if [[ "$line" == "Signed-off-by: "* ]]; then
-    error "Commit body contains a Signed-off-by tag"
+    if [[ "$line" == "Signed-off-by: "* ]]; then
+      error "Commit body contains a Signed-off-by tag"
+    fi
   fi
 
 done <"$commit_file"