/**
* @fileoverview Defines the core logic, schemas, and types for the git_diff tool.
* @module src/mcp-server/tools/gitDiff/logic
*/
import { execFile } from "child_process";
import { promisify } from "util";
import { z } from "zod";
import {
logger,
type RequestContext,
sanitization,
} from "../../../utils/index.js";
import { McpError, BaseErrorCode } from "../../../types-global/errors.js";
const execFileAsync = promisify(execFile);
// 1. DEFINE the Zod input schema.
export const GitDiffBaseSchema = z.object({
path: z
.string()
.default(".")
.describe(
"Path to the Git repository. Defaults to the directory set via `git_set_working_dir` for the session; set 'git_set_working_dir' if not set.",
),
commit1: z
.string()
.optional()
.describe("First commit, branch, or ref for comparison."),
commit2: z
.string()
.optional()
.describe("Second commit, branch, or ref for comparison."),
staged: z
.boolean()
.default(false)
.describe("Show diff of changes staged for the next commit."),
file: z
.string()
.optional()
.describe("Limit the diff output to a specific file path."),
includeUntracked: z
.boolean()
.default(false)
.describe("Include untracked files in the diff output."),
});
export const GitDiffInputSchema = GitDiffBaseSchema.refine(
(data) => !(data.staged && (data.commit1 || data.commit2)),
{
message: "Cannot use 'staged' option with specific commit references.",
path: ["staged"],
},
);
// 2. DEFINE the Zod response schema.
export const GitDiffOutputSchema = z.object({
success: z.boolean().describe("Indicates if the command was successful."),
diff: z
.string()
.describe(
"The diff output. Will be 'No changes found.' if there are no differences.",
),
message: z.string().describe("A summary message of the result."),
});
// 3. INFER and export TypeScript types.
export type GitDiffInput = z.infer<typeof GitDiffInputSchema>;
export type GitDiffOutput = z.infer<typeof GitDiffOutputSchema>;
async function getUntrackedFilesDiff(
targetPath: string,
context: RequestContext,
): Promise<string> {
const { stdout } = await execFileAsync("git", [
"-C",
targetPath,
"ls-files",
"--others",
"--exclude-standard",
]);
const untrackedFiles = stdout.trim().split("\n").filter(Boolean);
if (untrackedFiles.length === 0) return "";
let diffs = "";
for (const file of untrackedFiles) {
const { stdout: diffOut } = await execFileAsync("git", [
"-C",
targetPath,
"diff",
"--no-index",
"/dev/null",
file,
]).catch((err) => {
if (err.stdout) return { stdout: err.stdout };
logger.warning(`Failed to diff untracked file: ${file}`, {
...context,
error: err.message,
});
return { stdout: "" };
});
diffs += diffOut;
}
return diffs;
}
/**
* 4. IMPLEMENT the core logic function.
* @throws {McpError} If the logic encounters an unrecoverable issue.
*/
export async function diffGitChanges(
params: GitDiffInput,
context: RequestContext & { getWorkingDirectory: () => string | undefined },
): Promise<GitDiffOutput> {
const operation = "diffGitChanges";
logger.debug(`Executing ${operation}`, { ...context, params });
const workingDir = context.getWorkingDirectory();
if (params.path === "." && !workingDir) {
throw new McpError(
BaseErrorCode.VALIDATION_ERROR,
"No session working directory set. Please specify a 'path' or use 'git_set_working_dir' first.",
);
}
const targetPath = sanitization.sanitizePath(
params.path === "." ? workingDir! : params.path,
{ allowAbsolute: true },
).sanitizedPath;
const args = ["-C", targetPath, "diff"];
if (params.staged) {
args.push("--staged");
} else {
if (params.commit1) args.push(params.commit1);
if (params.commit2) args.push(params.commit2);
}
if (params.file) args.push("--", params.file);
logger.debug(`Executing command: git ${args.join(" ")}`, {
...context,
operation,
});
const { stdout } = await execFileAsync("git", args, {
maxBuffer: 1024 * 1024 * 20,
});
let combinedDiff = stdout;
if (params.includeUntracked) {
const untrackedDiff = await getUntrackedFilesDiff(targetPath, context);
if (untrackedDiff) {
combinedDiff += (combinedDiff ? "\n" : "") + untrackedDiff;
}
}
const noChanges = combinedDiff.trim() === "";
const message = noChanges
? "No changes found."
: `Diff generated successfully.${params.includeUntracked ? " Untracked files included." : ""}`;
return {
success: true,
diff: noChanges ? "No changes found." : combinedDiff,
message,
};
}
