Function handle_detect_changes

src/mcp/mcp.c:10292–10790

}

static char *handle_detect_changes(cbm_mcp_server_t *srv, const char *args) {
    char *project = get_project_arg(args);
    char *base_branch = cbm_mcp_get_string_arg(args, "base_branch");
    char *since = cbm_mcp_get_string_arg(args, "since");
    char *scope = cbm_mcp_get_string_arg(args, "scope");
    int depth = cbm_mcp_get_int_arg(args, "depth", MCP_DEFAULT_BFS_DEPTH);
    depth = clamp_mcp_depth(depth, "detect_changes");

    /* scope: "files" = just changed files, "symbols" = files + symbols (default) */
    bool want_symbols = !scope || strcmp(scope, "symbols") == 0 || strcmp(scope, "impact") == 0;

    /* `since` (e.g. "HEAD~10", "v0.5.0") is the documented diff base but was
     * previously parsed and never used: it takes precedence over base_branch.
     * Route it through base_branch so the shared shell-arg validation and the
     * existing `<base>...HEAD` (three-dot) diff apply unchanged — `since` thus
     * adopts the same merge-base semantics base_branch already uses. */
    if (since && since[0]) {
        free(base_branch);
        base_branch = since; /* transfer ownership */
        since = NULL;
    }
    free(since); /* no-op after the swap (since is NULL); frees it otherwise */

    if (!base_branch) {
        base_branch = heap_strdup("main");
    }

    /* Reject shell metacharacters, and a leading '-', in the user-supplied
     * branch name. base_branch is spliced into `git diff --name-only
     * "<base>"...HEAD`; a value starting with '-' would be read by git as an
     * option rather than a ref (e.g. `--output=<path>` writes the diff to an
     * arbitrary file). A real git ref never begins with '-'. */
    if (!cbm_validate_shell_arg(base_branch) || base_branch[0] == '-' ||
        !validate_windows_cmd_interpolation_arg(base_branch)) {
        free(project);
        free(base_branch);
        free(scope);
        return cbm_mcp_text_result("base_branch contains invalid characters", true);
    }

    char *root_path = get_project_root(srv, project);
    if (!root_path) {
        char *err = build_no_store_error(project);
        char *res = cbm_mcp_text_result(err, true);
        free(err);
        free(project);
        free(base_branch);
        free(scope);
        return res;
    }

    if (!validate_search_path_arg(root_path) ||
        !validate_windows_cmd_interpolation_arg(root_path)) {
        free(root_path);
        free(project);
        free(base_branch);
        free(scope);
        return cbm_mcp_text_result("project path contains invalid characters", true);