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Diffstat (limited to 'src/tools/clippy/src/docs/read_zero_byte_vec.txt')
-rw-r--r-- | src/tools/clippy/src/docs/read_zero_byte_vec.txt | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/tools/clippy/src/docs/read_zero_byte_vec.txt b/src/tools/clippy/src/docs/read_zero_byte_vec.txt new file mode 100644 index 000000000..cef5604e0 --- /dev/null +++ b/src/tools/clippy/src/docs/read_zero_byte_vec.txt @@ -0,0 +1,30 @@ +### What it does +This lint catches reads into a zero-length `Vec`. +Especially in the case of a call to `with_capacity`, this lint warns that read +gets the number of bytes from the `Vec`'s length, not its capacity. + +### Why is this bad? +Reading zero bytes is almost certainly not the intended behavior. + +### Known problems +In theory, a very unusual read implementation could assign some semantic meaning +to zero-byte reads. But it seems exceptionally unlikely that code intending to do +a zero-byte read would allocate a `Vec` for it. + +### Example +``` +use std::io; +fn foo<F: io::Read>(mut f: F) { + let mut data = Vec::with_capacity(100); + f.read(&mut data).unwrap(); +} +``` +Use instead: +``` +use std::io; +fn foo<F: io::Read>(mut f: F) { + let mut data = Vec::with_capacity(100); + data.resize(100, 0); + f.read(&mut data).unwrap(); +} +```
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