Function cbm_cmdline_append_arg

src/foundation/subprocess.c:236–273

Append one argv element to the command line using the Microsoft C runtime * quoting rules (see MS "Parsing C Command-Line Arguments"). CreateProcess takes * a SINGLE string that the child re-parses back into argv, so any element with a * space, tab or double-quote must be wrapped in quotes and its embedded quotes / * preceding backslashes escaped. Without this a JSON argument like * {"repo_pa

 * non-zero at JSON-arg parse, misattributed to the last-marked file). POSIX is
 * unaffected: the POSIX spawn path passes the argv array straight to execv. */
static size_t cbm_cmdline_append_arg(char *buf, size_t cap, size_t pos, const char *arg, bool first,
                                     bool *ovf) {
    if (!first) {
        pos = cbm_cmdline_put(buf, cap, pos, ' ', ovf);
    }
    pos = cbm_cmdline_put(buf, cap, pos, '"', ovf);
    for (const char *p = arg; *p;) {
        size_t nbs = 0;
        while (*p == '\\') {
            nbs++;
            p++;
        }
        if (*p == '\0') {
            /* Trailing backslashes precede the closing quote: double them so the
             * quote stays a delimiter, not an escaped literal. */
            for (size_t k = 0; k < nbs * 2; k++) {
                pos = cbm_cmdline_put(buf, cap, pos, '\\', ovf);
            }
            break;
        }
        if (*p == '"') {
            /* N backslashes then a quote -> 2N+1 backslashes then an escaped quote. */
            for (size_t k = 0; k < nbs * 2 + 1; k++) {
                pos = cbm_cmdline_put(buf, cap, pos, '\\', ovf);
            }
            pos = cbm_cmdline_put(buf, cap, pos, '"', ovf);
            p++;
        } else {
            for (size_t k = 0; k < nbs; k++) {
                pos = cbm_cmdline_put(buf, cap, pos, '\\', ovf);
            }
            pos = cbm_cmdline_put(buf, cap, pos, *p, ovf);
            p++;
        }
    }
    pos = cbm_cmdline_put(buf, cap, pos, '"', ovf);
    return pos;
}

/* Build a full Windows CreateProcess command line from a NULL-terminated argv,
 * applying the MS C runtime quoting rules so the child re-parses byte-identical