Annotation of /trunk/git/genchangelog

#!/usr/bin/env node

/**
 *  Copyright (C) 2024  OSN, Inc.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

"use strict";

const path = require("path");
const { existsSync } = require("fs");
const { exit } = require("process");
const { execSync } = require("child_process");
const { writeFile } = require("fs/promises");
const { parseArgs } = require("util");

const ME = path.basename(process.argv[1]);

function print(...args) {
    console.log(`${ME}: ${args.join(" ")}`);
}

function perror(...args) {
    console.error(`\x1b[0m${ME}: error: ${args.join(" ")}`);
}

function findInPath(executable) {
    for (const segment of process.env.PATH?.split(
        process.platform === "win32" ? ";" : ":"
    ) ?? []) {
        const executablePath = path.join(
            segment,
            executable + (process.platform === "win32" ? ".exe" : "")
        );

        if (existsSync(executablePath)) {
            return executablePath;
        }
    }

    return null;
}

function checkForGit() {
    const gitPath = findInPath("git");

    if (!gitPath) {
        perror("could not find git in $PATH");
        perror("please make sure git is installed and available in $PATH");
        exit(1);
    }

    return gitPath;
}

function getGitLog(gitPath) {
    try {
        return execSync(gitPath + " --no-pager log", { encoding: "utf8" });
    } catch {
        perror("command `git --no-pager log' failed");
        exit(1);
    }
}

function parseGitLog(gitLog) {
    const lines = gitLog.split("\n");
    const commits = [];

    for (let i = 0; i < lines.length; ) {
        if (!lines[i].startsWith("commit")) {
            i++;
            continue;
        }

        const [, hash] = lines[i++].split(" ");
        const headerProps = {};

        while (
            i < lines.length &&
            lines[i].trim() !== "" &&
            !/^\s/.test(lines[i])
        ) {
            const colonIndex = lines[i].indexOf(":");
            const name = lines[i].slice(0, colonIndex).toLowerCase();
            const value = lines[i].slice(colonIndex + 1).trim();
            headerProps[name] = value;
            i++;
        }

        const messageLines = [];

        while (i < lines.length && !lines[i].startsWith("commit")) {
            const lineToPush = lines[i++].replace(/^    /, "");

            if (!lineToPush) {
                continue;
            }

            messageLines.push(lineToPush);
        }

        let mindex = messageLines.length - 1;
        const footerProps = {};
        const validFooterProps = [
            "signed-off-by",
            "co-authored-by",
            "on-behalf-of",
        ];

        while (
            mindex >= 1 &&
            /^[A-Za-z0-9-]+: /.test(messageLines.at(mindex))
        ) {
            const messageLine = messageLines[mindex--];
            const colonIndex = messageLine.indexOf(":");
            const name = messageLine.slice(0, colonIndex).toLowerCase();

            if (!validFooterProps.includes(name)) {
                continue;
            }

            const value = messageLine.slice(colonIndex + 1).trim();

            if (name in footerProps && !Array.isArray(footerProps[name])) {
                footerProps[name] = [footerProps[name]];
            }

            if (Array.isArray(footerProps[name])) {
                footerProps[name].push(value);
            } else {
                footerProps[name] = value;
            }

            messageLines.splice(mindex - 1, 1);
        }

        const message = messageLines.join("\n");

        commits.push({
            hash,
            message,
            headerProps,
            footerProps,
            signedOffBy: footerProps["signed-off-by"],
            onBehalfOf: footerProps["on-behalf-of"],
            author: headerProps["author"],
            createdAt: new Date(headerProps["date"]),
        });
    }

    return commits;
}

function generateMarkdownChangelog(commits) {
    let output = "# Changelog\n\n";

    const grouppedCommitsByDate = {};

    for (const commit of commits) {
        const key = `${commit.createdAt
            .getUTCDate()
            .toString()
            .padStart(2, 0)}-${(commit.createdAt.getUTCMonth() + 1)
            .toString()
            .padStart(2, "0")}-${commit.createdAt.getUTCFullYear()}::${
            Array.isArray(commit.author)
                ? commit.author.join(":")
                : commit.author
        }`;
        grouppedCommitsByDate[key] ??= [];
        grouppedCommitsByDate[key].push(commit);
    }

    for (const key in grouppedCommitsByDate) {
        const [date, author] = key.split("::");
        output += `### ${date} [${author}]\n\n`;

        for (const commit of grouppedCommitsByDate[key]) {
            const newLineIndex = commit.message.indexOf("\n");
            output += `* ${commit.message.slice(0, newLineIndex === -1 ? undefined : newLineIndex)}\n`;
        }

        output += "\n";
    }

    return output;
}

function generateChangelog(commits) {
    let output = "";

    const grouppedCommitsByDate = {};

    for (const commit of commits) {
        const key = `${commit.createdAt
            .getUTCDate()
            .toString()
            .padStart(2, 0)}-${(commit.createdAt.getUTCMonth() + 1)
            .toString()
            .padStart(2, "0")}-${commit.createdAt.getUTCFullYear()}::${
            Array.isArray(commit.author)
                ? commit.author.join(":")
                : commit.author
        }`;
        grouppedCommitsByDate[key] ??= [];
        grouppedCommitsByDate[key].push(commit);
    }

    for (const key in grouppedCommitsByDate) {
        const separatorPosition = key.indexOf("::");
        const date = key.slice(0, separatorPosition);
        const commits = grouppedCommitsByDate[key];

        output += `${date}  ${
            Array.isArray(commits[0].author)
                ? commits[0].author.join(", ")
                : commits[0].author
        }\n\n`;

        for (const commit of commits) {
            output += `        ${commit.message.replaceAll(
                "\n",
                "\n        "
            )}\n\n`;
        }
    }

    return output.trim();
}

function printHelp() {
    console.log("Usage:");
    console.log(`  ${ME} [OPTION]...`);
    console.log("Generate a formatted ChangeLog from Git commit logs.");
    console.log();
    console.log("Options:");
    console.log("  -h, --help           Show this help and exit.");
    console.log("  -v, --version        Show this script's version.");
    console.log("  -f, --format=        Set the changelog format.");
    console.log("                       Supported formats are: plain,");
    console.log("                       markdown.");
    console.log("  -o, --output=<FILE>  Write the generated changelog to");
    console.log("                       a file instead of standard output.");
    console.log("      --no-overwrite   Disallow overwriting of the output");
    console.log("                       file if it exists already.");
    console.log();
    console.log("Send general inquiries, questions and bug reports");
    console.log("to <[email protected]>.");
}

function printVersion() {
    console.log("Copyright (C) 2024 OSN, Inc.");
    console.log(
        "License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>."
    );
    console.log(
        "This is free software: you are free to change and redistribute it."
    );
    console.log("There is NO WARRANTY, to the extent permitted by law.");
    console.log();
    console.log("Written by Ar Rakin.");
}

async function main() {
    let options;

    try {
        options = parseArgs({
            argv: process.argv.slice(1),
            strict: true,
            allowPositionals: false,
            options: {
                help: {
                    type: "boolean",
                    alias: "h",
                },
                version: {
                    type: "boolean",
                    alias: "v",
                },
                output: {
                    type: "string",
                    short: "o",
                },
                "no-overwrite": {
                    type: "boolean",
                },
                format: {
                    type: "string",
                    short: "f"
                }
            },
        }).values;
    } catch (error) {
        perror(`${error?.message ?? error}`);
        exit(1);
    }

    if (options.help) {
        printHelp();
        exit(0);
    }

    if (options.version) {
        printVersion();
        exit(0);
    }

    if (options.format && !["markdown", "plain"].includes(options.format)) {
        perror("option `--format` or `-f` only accepts one of the following: markdown, plain");
        exit(1);
    }

    if (!options.output && options["no-overwrite"]) {
        perror(
            "option `--no-overwrite' without `--output` does not make sense"
        );
        exit(1);
    }

    if (
        options.output &&
        options["no-overwrite"] &&
        existsSync(options.output)
    ) {
        perror(`${options.output}: cannot write changelog: File exists`);
        exit(1);
    }

    const gitPath = checkForGit();
    const gitLog = getGitLog(gitPath);
    const commits = parseGitLog(gitLog);
    const filteredCommits = commits.filter(
        (commit) =>
            !/Merge pull request #\d+ from|Merge branch '\S+' of/.test(
                commit.message
            )
    );
    const changelog = options.format === "markdown" ? generateMarkdownChangelog(filteredCommits) : generateChangelog(filteredCommits);

    if (options.output) {
        try {
            await writeFile(options.output, changelog);
        } catch (error) {
            perror(
                `${options.output}: failed to write changelog: ${
                    error?.message ?? error
                }`
            );
            exit(1);
        }

        print(`wrote generated changelog to ${options.output}`);
    } else {
        console.log(changelog);
    }
}

main();
1	rakinar2	11	#!/usr/bin/env node
2
3			/**
4			* Copyright (C) 2024 OSN, Inc.
5			*
6			* This program is free software: you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation, either version 3 of the License, or
9			* (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program. If not, see <https://www.gnu.org/licenses/>.
18			*/
19
20			"use strict";
21
22			const path = require("path");
23			const { existsSync } = require("fs");
24			const { exit } = require("process");
25			const { execSync } = require("child_process");
26			const { writeFile } = require("fs/promises");
27			const { parseArgs } = require("util");
28
29			const ME = path.basename(process.argv[1]);
30
31			function print(...args) {
32			console.log(`${ME}: ${args.join(" ")}`);
33			}
34
35			function perror(...args) {
36			console.error(`\x1b[0m${ME}: error: ${args.join(" ")}`);
37			}
38
39			function findInPath(executable) {
40	rakinar2	15	for (const segment of process.env.PATH?.split(
41			process.platform === "win32" ? ";" : ":"
42			) ?? []) {
43			const executablePath = path.join(
44			segment,
45			executable + (process.platform === "win32" ? ".exe" : "")
46			);
47
48	rakinar2	11	if (existsSync(executablePath)) {
49			return executablePath;
50			}
51			}
52
53			return null;
54			}
55
56			function checkForGit() {
57			const gitPath = findInPath("git");
58
59			if (!gitPath) {
60			perror("could not find git in $PATH");
61			perror("please make sure git is installed and available in $PATH");
62			exit(1);
63			}
64
65			return gitPath;
66			}
67
68			function getGitLog(gitPath) {
69			try {
70			return execSync(gitPath + " --no-pager log", { encoding: "utf8" });
71	rakinar2	15	} catch {
72	rakinar2	11	perror("command `git --no-pager log' failed");
73			exit(1);
74			}
75			}
76
77			function parseGitLog(gitLog) {
78			const lines = gitLog.split("\n");
79			const commits = [];
80
81			for (let i = 0; i < lines.length; ) {
82			if (!lines[i].startsWith("commit")) {
83			i++;
84			continue;
85			}
86
87	rakinar2	15	const [, hash] = lines[i++].split(" ");
88	rakinar2	11	const headerProps = {};
89
90	rakinar2	15	while (
91			i < lines.length &&
92			lines[i].trim() !== "" &&
93			!/^\s/.test(lines[i])
94			) {
95	rakinar2	11	const colonIndex = lines[i].indexOf(":");
96			const name = lines[i].slice(0, colonIndex).toLowerCase();
97			const value = lines[i].slice(colonIndex + 1).trim();
98			headerProps[name] = value;
99			i++;
100			}
101
102			const messageLines = [];
103
104			while (i < lines.length && !lines[i].startsWith("commit")) {
105			const lineToPush = lines[i++].replace(/^ /, "");
106
107			if (!lineToPush) {
108			continue;
109			}
110	rakinar2	15
111	rakinar2	11	messageLines.push(lineToPush);
112			}
113
114			let mindex = messageLines.length - 1;
115			const footerProps = {};
116	rakinar2	15	const validFooterProps = [
117			"signed-off-by",
118			"co-authored-by",
119			"on-behalf-of",
120			];
121
122			while (
123			mindex >= 1 &&
124			/^[A-Za-z0-9-]+: /.test(messageLines.at(mindex))
125			) {
126	rakinar2	11	const messageLine = messageLines[mindex--];
127			const colonIndex = messageLine.indexOf(":");
128			const name = messageLine.slice(0, colonIndex).toLowerCase();
129
130			if (!validFooterProps.includes(name)) {
131			continue;
132			}
133	rakinar2	15
134	rakinar2	11	const value = messageLine.slice(colonIndex + 1).trim();
135
136			if (name in footerProps && !Array.isArray(footerProps[name])) {
137			footerProps[name] = [footerProps[name]];
138			}
139
140			if (Array.isArray(footerProps[name])) {
141			footerProps[name].push(value);
142	rakinar2	15	} else {
143	rakinar2	11	footerProps[name] = value;
144			}
145
146			messageLines.splice(mindex - 1, 1);
147			}
148
149			const message = messageLines.join("\n");
150	rakinar2	15
151	rakinar2	11	commits.push({
152			hash,
153			message,
154			headerProps,
155			footerProps,
156			signedOffBy: footerProps["signed-off-by"],
157			onBehalfOf: footerProps["on-behalf-of"],
158			author: headerProps["author"],
159	rakinar2	15	createdAt: new Date(headerProps["date"]),
160	rakinar2	11	});
161			}
162
163			return commits;
164			}
165
166	rakinar2	54	function generateMarkdownChangelog(commits) {
167			let output = "# Changelog\n\n";
168
169			const grouppedCommitsByDate = {};
170
171			for (const commit of commits) {
172			const key = `${commit.createdAt
173			.getUTCDate()
174			.toString()
175			.padStart(2, 0)}-${(commit.createdAt.getUTCMonth() + 1)
176			.toString()
177			.padStart(2, "0")}-${commit.createdAt.getUTCFullYear()}::${
178			Array.isArray(commit.author)
179			? commit.author.join(":")
180			: commit.author
181			}`;
182			grouppedCommitsByDate[key] ??= [];
183			grouppedCommitsByDate[key].push(commit);
184			}
185
186			for (const key in grouppedCommitsByDate) {
187			const [date, author] = key.split("::");
188			output += `### ${date} [${author}]\n\n`;
189
190			for (const commit of grouppedCommitsByDate[key]) {
191			const newLineIndex = commit.message.indexOf("\n");
192			output += `* ${commit.message.slice(0, newLineIndex === -1 ? undefined : newLineIndex)}\n`;
193			}
194
195			output += "\n";
196			}
197
198			return output;
199			}
200
201	rakinar2	11	function generateChangelog(commits) {
202			let output = "";
203	rakinar2	15
204	rakinar2	11	const grouppedCommitsByDate = {};
205	rakinar2	15
206	rakinar2	11	for (const commit of commits) {
207	rakinar2	15	const key = `${commit.createdAt
208			.getUTCDate()
209			.toString()
210	rakinar2	34	.padStart(2, 0)}-${(commit.createdAt.getUTCMonth() + 1)
211	rakinar2	15	.toString()
212			.padStart(2, "0")}-${commit.createdAt.getUTCFullYear()}::${
213			Array.isArray(commit.author)
214			? commit.author.join(":")
215			: commit.author
216			}`;
217	rakinar2	11	grouppedCommitsByDate[key] ??= [];
218			grouppedCommitsByDate[key].push(commit);
219			}
220
221			for (const key in grouppedCommitsByDate) {
222			const separatorPosition = key.indexOf("::");
223			const date = key.slice(0, separatorPosition);
224			const commits = grouppedCommitsByDate[key];
225
226	rakinar2	15	output += `${date} ${
227			Array.isArray(commits[0].author)
228			? commits[0].author.join(", ")
229			: commits[0].author
230			}\n\n`;
231	rakinar2	11
232			for (const commit of commits) {
233	rakinar2	15	output += ` ${commit.message.replaceAll(
234			"\n",
235			"\n "
236			)}\n\n`;
237	rakinar2	11	}
238			}
239	rakinar2	15
240	rakinar2	11	return output.trim();
241			}
242
243			function printHelp() {
244			console.log("Usage:");
245			console.log(` ${ME} [OPTION]...`);
246			console.log("Generate a formatted ChangeLog from Git commit logs.");
247			console.log();
248			console.log("Options:");
249			console.log(" -h, --help Show this help and exit.");
250			console.log(" -v, --version Show this script's version.");
251	rakinar2	54	console.log(" -f, --format= Set the changelog format.");
252			console.log(" Supported formats are: plain,");
253			console.log(" markdown.");
254			console.log(" -o, --output=<FILE> Write the generated changelog to");
255	rakinar2	11	console.log(" a file instead of standard output.");
256			console.log(" --no-overwrite Disallow overwriting of the output");
257			console.log(" file if it exists already.");
258			console.log();
259			console.log("Send general inquiries, questions and bug reports");
260	rakinar2	20	console.log("to <[email protected]>.");
261	rakinar2	11	}
262
263			function printVersion() {
264			console.log("Copyright (C) 2024 OSN, Inc.");
265	rakinar2	15	console.log(
266			"License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>."
267			);
268			console.log(
269			"This is free software: you are free to change and redistribute it."
270			);
271	rakinar2	11	console.log("There is NO WARRANTY, to the extent permitted by law.");
272			console.log();
273			console.log("Written by Ar Rakin.");
274			}
275
276			async function main() {
277			let options;
278
279			try {
280			options = parseArgs({
281			argv: process.argv.slice(1),
282			strict: true,
283			allowPositionals: false,
284			options: {
285			help: {
286			type: "boolean",
287	rakinar2	15	alias: "h",
288	rakinar2	11	},
289			version: {
290			type: "boolean",
291	rakinar2	15	alias: "v",
292	rakinar2	11	},
293			output: {
294			type: "string",
295	rakinar2	15	short: "o",
296	rakinar2	11	},
297			"no-overwrite": {
298	rakinar2	15	type: "boolean",
299			},
300	rakinar2	54	format: {
301			type: "string",
302			short: "f"
303			}
304	rakinar2	15	},
305	rakinar2	11	}).values;
306	rakinar2	15	} catch (error) {
307	rakinar2	11	perror(`${error?.message ?? error}`);
308			exit(1);
309			}
310
311			if (options.help) {
312			printHelp();
313			exit(0);
314			}
315
316			if (options.version) {
317			printVersion();
318			exit(0);
319			}
320
321	rakinar2	54	if (options.format && !["markdown", "plain"].includes(options.format)) {
322			perror("option `--format` or `-f` only accepts one of the following: markdown, plain");
323			exit(1);
324			}
325
326	rakinar2	11	if (!options.output && options["no-overwrite"]) {
327	rakinar2	15	perror(
328			"option `--no-overwrite' without `--output` does not make sense"
329			);
330	rakinar2	11	exit(1);
331			}
332	rakinar2	15
333			if (
334			options.output &&
335			options["no-overwrite"] &&
336			existsSync(options.output)
337			) {
338	rakinar2	11	perror(`${options.output}: cannot write changelog: File exists`);
339			exit(1);
340			}
341	rakinar2	15
342	rakinar2	11	const gitPath = checkForGit();
343			const gitLog = getGitLog(gitPath);
344			const commits = parseGitLog(gitLog);
345	rakinar2	15	const filteredCommits = commits.filter(
346			(commit) =>
347			!/Merge pull request #\d+ from\|Merge branch '\S+' of/.test(
348			commit.message
349			)
350			);
351	rakinar2	54	const changelog = options.format === "markdown" ? generateMarkdownChangelog(filteredCommits) : generateChangelog(filteredCommits);
352	rakinar2	11
353	rakinar2	15	if (options.output) {
354	rakinar2	11	try {
355			await writeFile(options.output, changelog);
356	rakinar2	15	} catch (error) {
357			perror(
358			`${options.output}: failed to write changelog: ${
359			error?.message ?? error
360			}`
361			);
362	rakinar2	11	exit(1);
363			}
364
365			print(`wrote generated changelog to ${options.output}`);
366	rakinar2	15	} else {
367	rakinar2	11	console.log(changelog);
368			}
369			}
370
371			main();