feat: add linting of existing commit messages

Author: jvanbruegge

src/config.ts

@@ -33,6 +33,10 @@ const Config = t.type({
 
 export type Config = t.TypeOf<typeof Config>;
 
+export function getScopes(type: string, config: Config): string[] {
+    return config.scopeOverrides[type] ?? config.scopes;
+}
+
 export function parseConfig(path: string | undefined): Config {
     const json = path
         ? JSON.parse(readFileSync(path, { encoding: 'utf-8' }))

src/index.ts

@@ -4,6 +4,7 @@ import { resolve } from 'path';
 
 import { parseConfig } from './config';
 import { createCommitMessage } from './prompt';
+import { checkMessage } from './lint';
 import { renderMessage, parseMessage } from './message';
 
 const program = new Command();
@@ -49,7 +50,8 @@ function lintMessage(): void {
         encoding: 'utf-8',
     });
     const parsed = parseMessage(msg, config);
-    console.log(parsed);
+    checkMessage(parsed, config);
+    process.exitCode = 0;
 }
 
 function runInteractive(): void {

src/lint.ts

@@ -0,0 +1,77 @@
+import { Config, getScopes, ticketSeperatorRegex } from './config';
+import { Message } from './message';
+
+export function checkMessage(msg: Message, config: Config): void {
+    if (config.types.indexOf(msg.type) === -1) {
+        throw new Error(
+            `Expected 'type' to be one of '${config.types.join(', ')}', got '${
+                msg.type
+            }'`
+        );
+    }
+
+    const allowedScopes = getScopes(msg.type, config);
+    if (allowedScopes.length > 0 && !msg.scope) {
+        throw new Error('Expected a scope, but got none');
+    }
+
+    if (
+        msg.scope &&
+        !config.allowCustomScopes &&
+        allowedScopes.indexOf(msg.scope) === -1
+    ) {
+        throw new Error(
+            `Expected 'scope' to be one of '${allowedScopes.join(
+                ', '
+            )}', got '${msg.scope}'`
+        );
+    }
+
+    if (msg.body) {
+        checkWrap(msg.body, config.bodyWrap);
+    }
+    if (msg.breaking) {
+        if (
+            config.allowBreakingChanges.length > 0 &&
+            config.allowBreakingChanges.indexOf(msg.type) === -1
+        ) {
+            throw new Error(
+                `A BREAKING CHANGE is only allowed for the types '${config.allowBreakingChanges.join(
+                    ', '
+                )}', not for '${msg.type}'`
+            );
+        }
+        checkWrap(msg.breaking, config.bodyWrap);
+    }
+
+    if (msg.issuesClosed) {
+        for (const issue of msg.issuesClosed
+            .split(ticketSeperatorRegex(config))
+            .map(s => s.trim())) {
+            if (!issue.startsWith(config.ticketNumberPrefix)) {
+                throw new Error(
+                    `Expected ticket number to start with '${config.ticketNumberPrefix}', got '${issue}'`
+                );
+            }
+            const ticketNumber = issue.slice(
+                config.ticketNumberPrefix.length,
+                issue.length
+            );
+            if (isNaN(parseInt(ticketNumber))) {
+                throw new Error(
+                    `Expected ticket number to be a number, got '${ticketNumber}'`
+                );
+            }
+        }
+    }
+}
+
+function checkWrap(block: string, wrap: number) {
+    for (const line of block.split('\n')) {
+        if (line.length > wrap) {
+            throw new Error(
+                `Expected body to wrap after ${wrap} characters, but '${line}' has ${line.length}`
+            );
+        }
+    }
+}

src/message.ts

@@ -22,7 +22,7 @@ export function parseMessage(msg: string, config: Config): Message {
     if (!matches) {
         throw new Error(
             `expected subject to either have form '${config.typePrefix}<type>${config.typeSuffix}: <subject>' ` +
-                `or form '${config.typeSuffix}<type>${config.typeSuffix}(<scope>): <subject>'`
+                `or form '${config.typeSuffix}<type>${config.typeSuffix}(<scope>): <subject>', got '${lines[0]}'`
         );
     }
 
@@ -42,9 +42,9 @@ export function parseMessage(msg: string, config: Config): Message {
         } else if (lines[i].startsWith(config.breakingPrefix)) {
             isBody = false;
         } else if (isBody) {
-            body += lines[i] + ' ';
+            body += lines[i] + '\n';
         } else {
-            breaking += lines[i] + ' ';
+            breaking += lines[i] + '\n';
         }
     }
 

src/prompt.ts

@@ -2,7 +2,7 @@ import * as inquirer from 'inquirer';
 import { QuestionCollection, Separator, Answers } from 'inquirer';
 import { green, red } from 'chalk';
 
-import { Config, ticketSeperatorRegex } from './config';
+import { Config, getScopes, ticketSeperatorRegex } from './config';
 import { Message } from './message';
 
 export function createCommitMessage(config: Config): Promise<Message> {
@@ -79,6 +79,7 @@ export function createCommitMessage(config: Config): Promise<Message> {
             choices: config.allowBreakingChanges,
             when: answers =>
                 answers.breaking !== '' &&
+                config.allowBreakingChanges.length > 0 &&
                 config.allowBreakingChanges.indexOf(answers.type) === -1,
         },
         {
@@ -148,11 +149,9 @@ function filterSubject(subject: string, upperCase: boolean): string {
 
 function getChoices(config: Config): (answers: Answers) => string[] {
     return ({ type }) =>
-        config.scopes
-            .concat(config.scopeOverrides[type] ?? [])
-            .concat(
-                config.allowCustomScopes
-                    ? [(new Separator() as unknown) as string, 'custom']
-                    : []
-            );
+        getScopes(type, config).concat(
+            config.allowCustomScopes
+                ? [(new Separator() as unknown) as string, 'custom']
+                : []
+        );
 }