commitlint.config: add proper-revert-message rule

Author: tehraninasab

commitlint.config.ts

@@ -43,7 +43,12 @@ module.exports = {
         "too-many-spaces": [RuleConfigSeverity.Error, "always"],
         "commit-hash-alone": [RuleConfigSeverity.Error, "always"],
         "title-uppercase": [RuleConfigSeverity.Error, "always"],
+        "proper-revert-message": [RuleConfigSeverity.Error, "always"],
     },
+
+    // Commitlint automatically ignores some kinds of commits like Revert commit messages.
+    // We need to set this value to false to apply our rules on these messages.
+    defaultIgnores: false,
     plugins: [
         // TODO (ideas for more rules):
         // * Detect if paragraphs in body have been cropped too shortly (less than 64 chars), and suggest same auto-wrap command that body-soft-max-line-length suggests, since it unwraps and wraps (both).
@@ -118,6 +123,24 @@ module.exports = {
                     return Plugins.properIssueRefs(rawStr);
                 },
 
+                "proper-revert-message": ({
+                    header,
+                    body,
+                }: {
+                    header: any;
+                    body: any;
+                }) => {
+                    let bodyStr = Helpers.convertAnyToString(
+                        body,
+                        "body"
+                    ).trim();
+                    let headerStr = Helpers.convertAnyToString(
+                        header,
+                        "header"
+                    ).trim();
+                    return Plugins.properRevertMessage(headerStr, bodyStr);
+                },
+
                 "title-uppercase": ({ header }: { header: any }) => {
                     let headerStr = Helpers.convertAnyToString(
                         header,

commitlint/helpers.ts

@@ -22,13 +22,7 @@ export abstract class Helpers {
     ): string {
         if (potentialString === null || potentialString === undefined) {
             // otherwise, String(null) might give us the stupid string "null"
-            throw new Error(
-                "Unexpected " +
-                    paramName +
-                    "===null or " +
-                    paramName +
-                    "===undefined happened"
-            );
+            return "";
         }
         return String(potentialString);
     }

commitlint/plugins.ts

@@ -272,6 +272,24 @@ export abstract class Plugins {
         ];
     }
 
+    public static properRevertMessage(headerStr: string, bodyStr: string) {
+        let offence = false;
+
+        if (headerStr.match(/^[Rr]evert ".+"$/) !== null) {
+            // does msg have a body?
+            if (bodyStr !== "") {
+                let lines = bodyStr.split("\n");
+                offence =
+                    lines[0].match(/^This reverts commit [^ ]{40}\.$/) !==
+                        null && lines.length == 1;
+            } else {
+                offence = true;
+            }
+        }
+
+        return [!offence, `Please explain why you're reverting`];
+    }
+
     public static titleUppercase(headerStr: string) {
         let firstWord = headerStr.split(" ")[0];
         let offence =