Jra.80ch.test1

.github/workflows/80ch.sh

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+
+#**************************************************************************#
+#*                                                                        *#
+#*                                 OCaml                                  *#
+#*                                                                        *#
+#*                    James Rayman, Jane Street, New York                 *#
+#*                                                                        *#
+#*   Copyright 2025 Jane Street Group LLC                                 *#
+#*                                                                        *#
+#*   All rights reserved.  This file is distributed under the terms of    *#
+#*   the GNU Lesser General Public License version 2.1, with the          *#
+#*   special exception on linking described in the file LICENSE.          *#
+#*                                                                        *#
+#**************************************************************************#
+
+# 80ch.sh: A GitHub-actions-friendly script which finds lines added in the
+#          current feature which are longer than 80 characters. To be less
+#          annoying, 80ch.sh never fails, but instead emits warnings, and only
+#          checks a subset of all files (See SKIP FILES).
+
+set -u
+
+feature_base="HEAD^1" # GitHub automatically makes us a merge commit (HEAD),
+                      # so our feature base is just the first parent (HEAD^1)
+                      # of this merge commit
+
+find_diff() {
+# Iterate through all files changed since this branch forked off of main.
+#
+#  Separate file names with NULLs. This is      Read the next token
+#  standard for lists of files since file       |    Tokens are delimited
+#  names may contain newlines        |          |    |         with NULLs
+#                                    |-         |--- |-------
+git diff --name-only "$feature_base" -z | while read -d $'\0' -r changed_file
+#                                                             ^| ^^^^^^^^^^^|
+#                   Don't allow backslashes to escape characters            |
+#                                            Store the token in $changed_file
+do
+  # SKIP FILES
+
+  # Only check regular files that currently exist
+  [[ -f "$changed_file" ]] || continue
+
+  # Only check ml, mli, and mly files for long lines
+  [[ "$changed_file" =~ \.ml(i|y)?$ ]] || continue
+
+  # Don't check tests for long lines
+  # (a more sophisticated script would instead remove %%expect blocks)
+  [[ "$changed_file" == testsuite/tests/* ]] && continue
+
+  # Bash doesn't allow for comments on multiline commands, so excuse the
+  # workaround of putting groups of argument in a variable
+  f='--old-line-format= --unchanged-line-format= --new-line-format=%dn:%L'
+  #  |^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |^^^^^^^^^^^^^^^^^^^^^^^
+  #  Don't print deleted or unchanged lines      Show added lines (%L),
+  #                                              prepended with the line number
+  #                                              (%dn) and a colon
+
+  #                                                If $changed_file is new, then
+  #                                                `git show` will error, but
+  #                                                ignoring the error results in
+  #         Print the contents of $changed_file    a blank output, which is what
+  #         at the feature base                    we want
+  #         |------------------------------------- |----------
+  diff $f <(git show "$feature_base:$changed_file" 2>/dev/null) \
+          "$changed_file" \
+  | grep -E ":.{81}" | while read -r -d $'\n' long_line
+  # |^^^^^^^^^^^^^^^
+  # Search through the output of `diff`,
+  # looking for 81 characters after the line
+  # number and colon
+  do
+    line="${long_line#*:}"    # These parameter expansions split
+    number="${long_line%%:*}" # on the first colon
+
+    # Warning workflow command for GitHub Actions
+    printf '::error file=%s,line=%s,title=%s::%s\n' \
+      "$changed_file" "$number" \
+      'Line is longer than 80 characters' \
+      'Consider rewrapping this line'
+  done
+done
+}
+
+output="$(find_diff)"
+printf '%s' "$output"
+[[ -z "$output" ]] # if there is output, exit 1

.github/workflows/80ch.yml

@@ -0,0 +1,23 @@
+name: 80ch
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest]
+
+    steps:
+    - name: Checkout the Flambda backend repo
+      uses: actions/checkout@master
+
+    - name: Checkout the parent branch
+      run: git fetch origin HEAD --deepen 1
+
+    - name: Check for new >80 character lines
+      run: bash .github/workflows/80ch.sh

CONTRIBUTING.md

@@ -56,6 +56,9 @@ https://help.github.com/articles/allowing-changes-to-a-pull-request-branch-creat
 significantly delay the inclusion of an otherwise perfectly ok
 contribution.
 
+Only ml, mli, and mly files are subject to 80ch
+https://help.github.com/articles/allowing-changes-to-a-pull-request-branch-created-from-a-fork/
+
 ### Maintainers
 
 The current list of maintainers is as follows: