Function cbm_upsert_instructions

src/cli/cli.c:1335–1412

}

int cbm_upsert_instructions(const char *path, const char *content) {
    if (!path || !content) {
        return CLI_ERR;
    }

    size_t existing_len = 0;
    char *existing = read_file_str(path, &existing_len);

    /* Build the marker-wrapped section */
    size_t section_len = strlen(CMM_MARKER_START) + CLI_SKIP_ONE + strlen(content) +
                         strlen(CMM_MARKER_END) + CLI_SKIP_ONE;
    char *section = malloc(section_len + CLI_SKIP_ONE);
    if (!section) {
        free(existing);
        return CLI_ERR;
    }
    snprintf(section, section_len + SKIP_ONE, "%s\n%s%s\n", CMM_MARKER_START, content,
             CMM_MARKER_END);

    if (!existing) {
        /* File doesn't exist — create with just the section */
        int rc = write_file_str(path, section);
        free(section);
        return rc;
    }

    /* Check if markers already exist */
    char *start = strstr(existing, CMM_MARKER_START);
    char *end = start ? strstr(start, CMM_MARKER_END) : NULL;

    char *result;
    if (start && end) {
        /* Replace between markers (including markers themselves) */
        end += strlen(CMM_MARKER_END);
        /* Skip trailing newline after end marker */
        if (*end == '\n') {
            end++;
        }

        size_t prefix_len = (size_t)(start - existing);
        size_t suffix_len = strlen(end);
        size_t new_len = prefix_len + strlen(section) + suffix_len;
        result = malloc(new_len + CLI_SKIP_ONE);
        if (!result) {
            free(existing);
            free(section);
            return CLI_ERR;
        }
        memcpy(result, existing, prefix_len);
        memcpy(result + prefix_len, section, strlen(section));
        memcpy(result + prefix_len + strlen(section), end, suffix_len);
        result[new_len] = '\0';
    } else {
        /* Append section */
        size_t new_len = existing_len + CLI_SKIP_ONE + strlen(section);
        if (new_len > (size_t)CLI_MB_10 * CLI_MB_FACTOR) { /* 10 MB safety cap */
            free(existing);
            free(section);