commit c72aba4fb58cdc33a63adeb0c537d513293a8c4d
author Googler <noreply@google.com> Wed Oct 23 08:59:27 2024 -0700
committer Copybara-Service <copybara-worker@google.com> Wed Oct 23 09:00:40 2024 -0700
tree 2e4591a7ecfaca3aaf6d7973b0109f1d5245c436
parent 3715cd6e8ea027b443dc80276a77fcd95ed1e357

Add a warning that `$(SRCS)` and `$(OUTS)` are in fact not safe to interpolate into commands without processing.

The fix suggested here was necessary when a genrule consumed a target with a `'` in its name (which in a turn consumed a source file also with this character in its name).

There the approach used was:
```python
def _extract_makevar_array(name):
    """
    Extracts the contents of the make variable `$(NAME)` into an array variable `$${NAME}`.

    This makes it possible to correctly handle cases where `$(NAME)` contains special characters.
    It probably still doesn't work if `$(NAME)` contains spaces.
    """
    return """
mapfile %s <<< "$$(sed -e 's/ /\\n/g' <<'a_long_unique_identifier'
$(%s)
a_long_unique_identifier
)"
""" % (name, name)
```
and passing `cmd = _extract_makevar_array("SRCS") + """for F in "$${SRCS[@]}"; do echo $F; done"""`.

PiperOrigin-RevId: 688984848
Change-Id: I798372778e4b46252902731585cb0b55f1166f36