bug: Mutating underlying `&'static str`

[ParkMyCar]

In the yet to be release API CompactString::from_static_str, you can create an instance of CompactString, backed by a &'static str. There are a few APIs on CompactString though that assume we own the underlying data, and thus modify it directly, e.g.

• retain()
• drain()
• insert_str()
• replace_range()

We need to fix these APIs to copy the underlying data before modifying it

[NobodyXu]

retain() should be ok, since it should invoke as_mut_buf which already handle this https://github.com/ParkMyCar/compact_str/blob/df20a0148ecd5df509f82a20b12c45f77a45471e/compact_str/src/repr/mod.rs#L497

[NobodyXu]

drain() also calls as_mut_buf(), so it should be ok.

[NobodyXu]

insert() calls reserve() which handles this, so it should be also ok.

[NobodyXu]

replace_range*() calls as_mut_ptr() or reserve() (in replace_range_grow()), so they should be ok.

[ParkMyCar]

@NobodyXu my bad 🤦‍♂️ you're totally right, thank you for looking into this! I updated the branch that adds fuzz coverage, will run it for a bit, and then release v0.8.0-beta!

[NobodyXu]

No worries! Better to be careful than rush to fix the bug later.