Anchor build breaks when adding chrono package

Question

I have tried to add the latest version of chrono but seems to fail throwing multiple errors.

• Anchor version: anchor-cli 0.25.0
• Rust version: rustc 1.63.0 (4b91a6ea7 2022-08-08)
• Chrono version: 0.4.22
• Rustup toolchain (using mac with chip M1):

  stable-aarch64-apple-darwin (default)
  

Error log when executing anchor build:

error[E0432]: unresolved import `self::inner`
 --> src/sys.rs:3:15
  |
3 | pub use self::inner::*;
  |               ^^^^^ could not find `inner` in `self`

error[E0433]: failed to resolve: could not find `SteadyTime` in `sys`
   --> src/lib.rs:251:25
    |
251 |         SteadyTime(sys::SteadyTime::now())
    |                         ^^^^^^^^^^ could not find `SteadyTime` in `sys`

error[E0425]: cannot find function `get_time` in module `sys`
   --> src/lib.rs:153:28
    |
153 |     let (sec, nsec) = sys::get_time();
    |                            ^^^^^^^^ not found in `sys`

error[E0425]: cannot find function `get_precise_ns` in module `sys`
   --> src/lib.rs:164:10
    |
164 |     sys::get_precise_ns()
    |          ^^^^^^^^^^^^^^ not found in `sys`

error[E0412]: cannot find type `SteadyTime` in module `sys`
   --> src/lib.rs:246:28
    |
246 | pub struct SteadyTime(sys::SteadyTime);
    |                            ^^^^^^^^^^ not found in `sys`

error[E0425]: cannot find function `time_to_utc_tm` in module `sys`
   --> src/lib.rs:408:10
    |
408 |     sys::time_to_utc_tm(sec, &mut tm);
    |          ^^^^^^^^^^^^^^ not found in `sys`

error[E0425]: cannot find function `time_to_local_tm` in module `sys`
   --> src/lib.rs:422:10
    |
422 |     sys::time_to_local_tm(sec, &mut tm);
    |          ^^^^^^^^^^^^^^^^ not found in `sys`

error[E0425]: cannot find function `utc_tm_to_time` in module `sys`
   --> src/lib.rs:436:23
    |
436 |             0 => sys::utc_tm_to_time(self),
    |                       ^^^^^^^^^^^^^^ not found in `sys`

error[E0425]: cannot find function `local_tm_to_time` in module `sys`
   --> src/lib.rs:437:23
    |
437 |             _ => sys::local_tm_to_time(self)
    |                       ^^^^^^^^^^^^^^^^ not found in `sys`

Answer 1

Seems like there are two ways of retrieving Clock according Solana docs:

1. Passing SYSVAR_CLOCK_PUBKEY into an instruction

   let clock = Clock::from_account_info(&sysvar_clock_pubkey)?;
   let current_timestamp = clock.unix_timestamp;
   

2. Accessing Clock directly inside an instruction.

   let clock = Clock::get()?;
   let current_timestamp = clock.unix_timestamp;
   

Looks like we shouldn't use external libs for this.