github: Add more context to pull requests

Add code to fetch and decode CODEOWNERS and automatically @ people in
the review.

Create a new file, .github/path-rules.txt that has a set of paths to
match and specific warnings about that part of the tree. We'll use this
to try to wave off pull requests in certain areas of the tree, as well
as remind people when contrib is involved, etc.

Sponsored by:		Netflix

.github/path-rules.txt

@@ -0,0 +1,10 @@
+#
+# Format the similar to CODEOWNERS: Each line has a path, whitespace and a
+# message for contributors.
+#
+sys/contrib/device-tree	:caution: No changes should be made here by pull request
+# Catch all
+contrib		:warning: Contributed software usually managed by vendor branch
+crypto		:warning: Contributed crypto software usually managed by vendor branch
+sys/contrib	:warning: Contributed software usually managed by vendor branch
+sys/crypto	:warning: Contributed crypto software usually managed by vendor branch

.github/workflows/checklist.yml

@@ -36,11 +36,49 @@ jobs:
               pull_number: context.issue.number
             });
 
+            /* Get owners */
+
+            let owners = [];
+            const { data: ownerData } = await github.rest.repos.getContent({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              path: '.github/CODEOWNERS',
+              ref: context.payload.pull_request.base.ref // Or a specific branch
+            });
+            const oc = Buffer.from(ownerData.content, 'base64').toString();
+            owners = oc.split(/\r?\n/)
+              .map(line => line.trim())
+              // Filter out comments and empty lines
+              .filter(line => line && !line.startsWith('#'))
+              .map(line => {
+                // Split by the first block of whitespace to separate path and message
+                 const [path, ...ownerParts] = line.substring(1).split(/\s+/);
+                 return { path, owner: ownerParts.join(' ') };
+            });
+
+            /* Get rules -- maybe refactor to a function for ownerPath too */
+            let rules = [];
+            const { data: rulesData } = await github.rest.repos.getContent({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              path: '.github/path-rules.txt',
+              ref: context.payload.pull_request.base.ref // Or a specific branch
+            });
+            const rc = Buffer.from(rulesData.content, 'base64').toString();
+            rules = rc.split(/\r?\n/)
+              .map(line => line.trim())
+              // Filter out comments and empty lines
+              .filter(line => line && !line.startsWith('#'))
+              .map(line => {
+                // Split by the first block of whitespace to separate path and message
+                const [path, ...messageParts] = line.split(/\s+/);
+                return { path, message: messageParts.join(' ') };
+            });
+
             let checklist = {};
             let checklist_len = 0;
             let comment_id = -1;
 
-            const msg_prefix = "Thank you for taking the time to contribute to FreeBSD!\n";
             const addToChecklist = (msg, sha) => {
               if (!checklist[msg]) {
                 checklist[msg] = [];
@@ -72,6 +110,43 @@ jobs:
                 addToChecklist("Real email address is needed", commit.sha);
             }
 
+            /* Check for different paths that have issues and/or owners */
+            const { data: files } = await github.rest.pulls.listFiles({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              pull_number: context.payload.pull_request.number,
+            });
+
+            let infolist = {};
+            let infolist_len = 0;
+            const addToInfolist = (msg) => {
+              if (!infolist[msg]) {
+                infolist[msg] = [];
+                infolist_len++;
+              }
+            }
+
+            /* Give advice based on what's in the commit */
+            for (const file of files) {
+              for (const owner of owners) {
+                if (file.filename.startsWith(owner.path)) {
+                  addToInfolist("> [!IMPORTANT]\n> " + owner.owner + " wants to review changes to " + owner.path + "\n");
+                }
+              }
+              for (const rule of rules) {
+                // Consider regexp in the future maybe?
+                if (file.filename.startsWith(rule.path)) {
+                  if (rule.message.startsWith(":caution: ")) {
+                    addToInfolist("> [!CAUTION]\n> " + rule.path + ": " + rule.message.substring(10) + "\n");
+                  } else if (rule.message.startsWith(":warning: ")) {
+                    addToInfolist("> [!WARNING]\n> " + rule.path + ": " + rule.message.substring(10) + "\n");
+                  } else {
+                    addToInfolist("> [!IMPORTANT]\n> " + rule.path + ": " + rule.message + "\n");
+                  }
+                }
+              }
+            }
+
             /* Check if we've commented before. */
             for (const comment of comments) {
               if (comment.user.login == "github-actions[bot]") {
@@ -80,17 +155,28 @@ jobs:
               }
             }
 
-            if (checklist_len != 0) {
-              let msg = msg_prefix +
-                "There " + (checklist_len > 1 ? "are a few issues that need " : "is an issue that needs ") +
-                "to be fixed:\n";
+            const msg_prefix = "Thank you for taking the time to contribute to FreeBSD!\n\n";
+            if (checklist_len != 0 || infolist_len != 0) {
+              let msg = msg_prefix;
               let comment_func = comment_id == -1 ? github.rest.issues.createComment : github.rest.issues.updateComment;
+              if (checklist_len != 0) {
+                msg +=
+                  "There " + (checklist_len > 1 ? "are a few issues that need " : "is an issue that needs ") +
+                  "to be resolved:\n";
 
-              /* Loop for each key in "checklist". */
-              for (const c in checklist)
-                msg += "- " + c + " (" + checklist[c].join(", ") + ")\n";
-              msg += "\nPlease review [CONTRIBUTING.md](https://github.com/freebsd/freebsd-src/blob/main/CONTRIBUTING.md), then update and push your branch again.\n"
-
+                /* Loop for each key in "checklist". */
+                for (const c in checklist)
+                  msg += "- " + c + " (" + checklist[c].join(", ") + ")\n";
+                msg += "\n> [!NOTE]\n> Please review [CONTRIBUTING.md](https://github.com/freebsd/freebsd-src/blob/main/CONTRIBUTING.md), then update and push your branch again.\n\n"
+              } else {
+                let msg = "No Issues found.\n\n";
+              }
+              if (infolist_len != 0) {
+                msg += "Some of files have special handling:\n"
+                for (const i in infolist)
+                  msg += i + "\n";
+                msg += "\n\n";
+              }
               comment_func({
                 owner: context.repo.owner,
                 repo: context.repo.repo,