Implement `git config`

This is also basic:

git config key             # To read a value
git config key value       # To set a value
git config --unset key     # To delete a value

As noted, --list is not possible to implement currently.

packages/git/src/subcommands/__exports__.js

@@ -19,6 +19,7 @@
 // Generated by /tools/gen.js
 import module_add from './add.js'
 import module_commit from './commit.js'
+import module_config from './config.js'
 import module_help from './help.js'
 import module_init from './init.js'
 import module_log from './log.js'
@@ -28,6 +29,7 @@ import module_version from './version.js'
 export default {
     "add": module_add,
     "commit": module_commit,
+    "config": module_config,
     "help": module_help,
     "init": module_init,
     "log": module_log,

packages/git/src/subcommands/config.js

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2024  Puter Technologies Inc.
+ *
+ * This file is part of Puter's Git client.
+ *
+ * Puter's Git client is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+import git from 'isomorphic-git';
+import { find_repo_root } from '../git-helpers.js';
+import { SHOW_USAGE } from '../help.js';
+
+export default {
+    name: 'config',
+    usage: ['git config name', 'git config name value', 'git config --unset name'],
+    description: 'Get or set git configuration options.',
+    args: {
+        allowPositionals: true,
+        options: {
+            'unset': {
+                description: 'Remove the matching line from the config.',
+                type: 'boolean',
+            },
+            // TODO: --list, which doesn't have a isomorphic-git command yet.
+            //  See https://github.com/isomorphic-git/isomorphic-git/issues/1917
+        },
+    },
+    execute: async (ctx) => {
+        const { io, fs, env, args } = ctx;
+        const { stdout, stderr } = io;
+        const { options, positionals } = args;
+
+        if (positionals.length === 0 || positionals.length > 2)
+            throw SHOW_USAGE;
+
+        const key = positionals.shift();
+        const value = positionals.shift();
+
+        const { repository_dir, git_dir } = await find_repo_root(fs, env.PWD);
+
+        if (value || options.unset) {
+            // Set it
+            // TODO: If --unset AND we have a value, we should only remove an entry that has that value
+            await git.setConfig({
+                fs,
+                dir: repository_dir,
+                gitdir: git_dir,
+                path: key,
+                value: options.unset ? undefined : value,
+            });
+            return;
+        }
+
+        // Get it
+        const result = await git.getConfig({
+            fs,
+            dir: repository_dir,
+            gitdir: git_dir,
+            path: key,
+        });
+        if (result === undefined) {
+            // Not found, so return 1
+            return 1;
+        }
+        stdout(result);
+    }
+}