Add clippy lint GitHub Actions CI

[weiji14]

Run cargo clippy --all-targets --all-features on Continuous Integration on every Pull Request and push to main.

TODO:

• Add clippy lint CI, adapted from https://doc.rust-lang.org/stable/clippy/continuous_integration/github_actions.html
• Fix clippy lints (do after some other refactoring is complete in other PRs)

[weiji14]

Copy of clippy lint errors from https://github.com/georust/geotiff/actions/runs/9116866203/job/25066420149?pr=12#step:3:31:

error: name `BYTE` contains a capitalized acronym
 --> src/lowlevel.rs:4:10
  |
4 | pub type BYTE      = u8;
  |          ^^^^ help: consider making the acronym lowercase, except the initial letter: `Byte`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms
  = note: `-D clippy::upper-case-acronyms` implied by `-D warnings`
  = help: to override `-D warnings` add `#[allow(clippy::upper_case_acronyms)]`

error: name `SHORT` contains a capitalized acronym
 --> src/lowlevel.rs:5:10
  |
5 | pub type SHORT     = u16;
  |          ^^^^^ help: consider making the acronym lowercase, except the initial letter: `Short`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `LONG` contains a capitalized acronym
 --> src/lowlevel.rs:6:10
  |
6 | pub type LONG      = u32;
  |          ^^^^ help: consider making the acronym lowercase, except the initial letter: `Long`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `ASCII` contains a capitalized acronym
 --> src/lowlevel.rs:7:10
  |
7 | pub type ASCII     = String;
  |          ^^^^^ help: consider making the acronym lowercase, except the initial letter (notice the capitalization): `Ascii`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `RATIONAL` contains a capitalized acronym
 --> src/lowlevel.rs:8:10
  |
8 | pub type RATIONAL  = (u32, u32);
  |          ^^^^^^^^ help: consider making the acronym lowercase, except the initial letter: `Rational`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `SBYTE` contains a capitalized acronym
 --> src/lowlevel.rs:9:10
  |
9 | pub type SBYTE     = i8;
  |          ^^^^^ help: consider making the acronym lowercase, except the initial letter: `Sbyte`
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `SSHORT` contains a capitalized acronym
  --> src/lowlevel.rs:10:10
   |
10 | pub type SSHORT    = i16;
   |          ^^^^^^ help: consider making the acronym lowercase, except the initial letter: `Sshort`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `SLONG` contains a capitalized acronym
  --> src/lowlevel.rs:11:10
   |
11 | pub type SLONG     = i32;
   |          ^^^^^ help: consider making the acronym lowercase, except the initial letter: `Slong`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `SRATIONAL` contains a capitalized acronym
  --> src/lowlevel.rs:12:10
   |
12 | pub type SRATIONAL = (i32, i32);
   |          ^^^^^^^^^ help: consider making the acronym lowercase, except the initial letter: `Srational`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `FLOAT` contains a capitalized acronym
  --> src/lowlevel.rs:13:10
   |
13 | pub type FLOAT     = f32;
   |          ^^^^^ help: consider making the acronym lowercase, except the initial letter: `Float`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `DOUBLE` contains a capitalized acronym
  --> src/lowlevel.rs:14:10
   |
14 | pub type DOUBLE    = f64;
   |          ^^^^^^ help: consider making the acronym lowercase, except the initial letter: `Double`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: all variants have the same postfix: `Value`
  --> src/lowlevel.rs:65:1
   |
65 | / pub enum TagValue {
66 | |     ByteValue(BYTE),
67 | |     AsciiValue(ASCII),
68 | |     ShortValue(SHORT),
...  |
76 | |     DoubleValue(DOUBLE),
77 | | }
   | |_^
   |
   = help: remove the postfixes and use full paths to the variants instead of glob imports
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#enum_variant_names
   = note: `-D clippy::enum-variant-names` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::enum_variant_names)]`

error: name `LZW` contains a capitalized acronym
  --> src/lowlevel.rs:93:5
   |
93 |     LZW      = 5,
   |     ^^^ help: consider making the acronym lowercase, except the initial letter (notice the capitalization): `Lzw`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `OJPEG` contains a capitalized acronym
  --> src/lowlevel.rs:94:5
   |
94 |     OJPEG    = 6,
   |     ^^^^^ help: consider making the acronym lowercase, except the initial letter: `Ojpeg`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `JPEG` contains a capitalized acronym
  --> src/lowlevel.rs:95:5
   |
95 |     JPEG     = 7,
   |     ^^^^ help: consider making the acronym lowercase, except the initial letter: `Jpeg`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: name `RGB` contains a capitalized acronym
   --> src/lowlevel.rs:124:5
    |
124 |     RGB,
    |     ^^^ help: consider making the acronym lowercase, except the initial letter: `Rgb`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#upper_case_acronyms

error: the borrowed expression implements the required traits
  --> src/reader.rs:25:37
   |
25 |         let mut reader = File::open(&filepath)?;
   |                                     ^^^^^^^^^ help: change this to: `filepath`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrows_for_generic_args
   = note: `-D clippy::needless-borrows-for-generic-args` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::needless_borrows_for_generic_args)]`

error: useless use of `format!`
  --> src/reader.rs:45:54
   |
45 |             None => Err(Error::new(ErrorKind::Other, format!("Invalid byte order in header."))),
   |                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `"Invalid byte order in header.".to_string()`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format
   = note: `-D clippy::useless-format` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::useless_format)]`

error: you don't need to add `&` to all patterns
   --> src/reader.rs:124:9
    |
124 | /         match tpe {
125 | |             &TagType::ByteTag => TagValue::ByteValue(vec[0]),
126 | |             &TagType::ASCIITag => TagValue::AsciiValue(String::from_utf8_lossy(&vec).to_string()),
127 | |             &TagType::ShortTag => TagValue::ShortValue(Endian::read_u16(&vec[..])),
...   |
138 | |             &TagType::UndefinedTag => TagValue::ByteValue(0),
139 | |         }
    | |_________^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#match_ref_pats
    = note: `-D clippy::match-ref-pats` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::match_ref_pats)]`
help: instead of prefixing all patterns with `&`, you can dereference the expression
    |
124 ~         match *tpe {
125 ~             TagType::ByteTag => TagValue::ByteValue(vec[0]),
126 ~             TagType::ASCIITag => TagValue::AsciiValue(String::from_utf8_lossy(&vec).to_string()),
127 ~             TagType::ShortTag => TagValue::ShortValue(Endian::read_u16(&vec[..])),
128 ~             TagType::LongTag => TagValue::LongValue(Endian::read_u32(&vec[..])),
129 ~             TagType::RationalTag => TagValue::RationalValue((Endian::read_u32(&vec[..(len / 2)]),
130 |                                                               Endian::read_u32(&vec[(len / 2)..]))),
131 ~             TagType::SignedByteTag => TagValue::SignedByteValue(vec[0] as i8),
132 ~             TagType::SignedShortTag => TagValue::SignedShortValue(Endian::read_i16(&vec[..])),
133 ~             TagType::SignedLongTag => TagValue::SignedLongValue(Endian::read_i32(&vec[..])),
134 ~             TagType::SignedRationalTag => TagValue::SignedRationalValue((Endian::read_i32(&vec[..(len / 2)]),
135 |                                                                           Endian::read_i32(&vec[(len / 2)..]))),
136 ~             TagType::FloatTag => TagValue::FloatValue(Endian::read_f32(&vec[..])),
137 ~             TagType::DoubleTag => TagValue::DoubleValue(Endian::read_f64(&vec[..])),
138 ~             TagType::UndefinedTag => TagValue::ByteValue(0),
    |

error: casting integer literal to `usize` is unnecessary
   --> src/reader.rs:147:18
    |
147 |             0 => 0 as usize,
    |                  ^^^^^^^^^^ help: try: `0_usize`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast
    = note: `-D clippy::unnecessary-cast` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::unnecessary_cast)]`

error: casting integer literal to `u16` is unnecessary
   --> src/reader.rs:259:18
    |
259 |             _ => 0 as u16,
    |                  ^^^^^^^^ help: try: `0_u16`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

error: casting integer literal to `u16` is unnecessary
   --> src/reader.rs:263:18
    |
263 |             _ => 0 as u16,
    |                  ^^^^^^^^ help: try: `0_u16`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

error: casting integer literal to `u16` is unnecessary
   --> src/reader.rs:267:18
    |
267 |             _ => 0 as u16,
    |                  ^^^^^^^^ help: try: `0_u16`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

error: casting integer literal to `u16` is unnecessary
   --> src/reader.rs:281:18
    |
281 |             _ => 0 as u16,
    |                  ^^^^^^^^ help: try: `0_u16`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
   --> src/reader.rs:285:13
    |
285 | /             match v {
286 | |                 TagValue::LongValue(v) => offsets.push(*v),
287 | |                 _ => (),
288 | |             };
    | |_____________^ help: try: `if let TagValue::LongValue(v) = v { offsets.push(*v) }`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_match
    = note: `-D clippy::single-match` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::single_match)]`

error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
   --> src/reader.rs:292:13
    |
292 | /             match v {
293 | |                 TagValue::LongValue(v) => byte_counts.push(*v),
294 | |                 _ => (),
295 | |             };
    | |_____________^ help: try: `if let TagValue::LongValue(v) = v { byte_counts.push(*v) }`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#single_match

error: casting to the same type is unnecessary (`usize` -> `usize`)
   --> src/reader.rs:314:30
    |
314 |                 if curr_y >= img[curr_x].len() as usize {
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `img[curr_x].len()`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast

error: could not compile `geotiff` (lib) due to 27 previous errors
warning: build failed, waiting for other jobs to finish...
error: could not compile `geotiff` (lib test) due to 27 previous errors
Error: Process completed with exit code 101.

Will fix these lint errors after a couple of other refactoring PRs.

[weiji14]

Most clippy lints resolved after big refactoring in #17. Debating on whether to enable other clippy lint groups listed at https://doc.rust-lang.org/stable/clippy/index.html 🤔

Edit: Will just go with the default lint groups for now and add more as needed.