date: fails to parse +N and -N in absolute time string as a time zone

[jfinkels]

Environment: Ubuntu 20.04, uutils main branch (git commit 88cdf16), GNU coreutils v8.30

Steps to reproduce:

TZ=UTC0 date -d '1997-01-19 08:17:48 +0'

What happens now: uutils date terminates with an error because it doesn't understand the +0 time zone:

date: invalid date '1997-01-19 08:17:48 +0'

If you remove the +0, then uutils date does successfully parse the date string.

What I expected to happen: GNU date successfully interprets the +0 as a time zone:

Sun 19 Jan 1997 08:17:48 AM UTC

Notes: this is causing a test failure in GNU test file tests/date/date.pl.

[Felle33]

Making some tests, the code can sucessfully parse the strings TZ=UTC0 date -d '1997-01-19 08:17:48 +0000' and TZ=UTC0 date -d '1997-01-19 08:17:48 +00:00'.
We could try to parse the timezone and then pass the right argument to the function parse_datetime::parse_datetime_at_date(...).
What do you think?

[jfinkels]

Maybe the parse_datetime_at_date function in https://github.com/uutils/parse_datetime just needs to be updated to understand the string "+0", etc.?

[Felle33]

Inspecting the code, I see that they try to parse also the timezone, but since %z accepts only 4 digits (i.e +0000) or 4 digits separated by : (i.e +00:00), the function returns an error

[jfinkels]

I'm proposing adding support for this to parse_datetime here: uutils/parse_datetime#101

[jfinkels]

Apparently my pull request uutils/parse_datetime#101 was not sufficient, I'll keep investigating.

[jfinkels]

Pull request uutils/parse_datetime#102 should have provided a basic implementation of this feature, and I expected it to become available in the just released version of parse_datetime 0.7.0, but it is not working as I expected. Maybe there was an issue with the release of the crate?

For example, after cargo new mytest && cargo add [email protected], this basic program

use parse_datetime::parse_datetime;

fn main() {
    dbg!(parse_datetime("1997-01-19 08:17:48 +0").unwrap());
}

when executed with cargo run fails with

thread 'main' panicked at src/main.rs:4:51:
called `Result::unwrap()` on an `Err` value: InvalidInput
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[sylvestre]

i just tagged the release + cargo publish

[jfinkels]

Hmm is it possible the tag is on the wrong commit? This is the log from the parse_datetime repository. The tag v0.7.0 is on a commit that branches away from the main sequence, and it doesn't include my commit "Parse datetimes with single digit timezone offset":

$ git log -9 --all --oneline --graph
*   eda2422 (HEAD -> main, upstream/main) Merge pull request #103 from jfinkels/parse-datetime-with-single-digit-offset-t-sep
|\  
| * c948274 Parse datetime with T separator and digit offset
|/  
*   b209341 Merge pull request #105 from sylvestre/0.7.0
|\  
| * 9cd22af prepare new release 0.7.0
|/  
*   a7061bc Merge pull request #102 from jfinkels/parse-datetime-with-single-digit-offset
|\  
| * ea49dc9 Parse datetimes with single digit timezone offset
|/  
| * ea52a79 (tag: v0.7.0) prepare new release 0.7.0
|/  
*   938aa96 Merge pull request #100 from jfinkels/add-months-overflow-surplus-days
|\  
| * 90d22a2 Overflow surplus days when adding months to a date

[sylvestre]

nope, it just misses
Parse datetime with T separator and digit offset

you can see the code of the lib here:
~/.cargo/registry/src/index.crates.io-*/parse_datetime-0.7.0/

[jfinkels]

I checked in ~/.cargo/registry/src/index.crates.io-*/parse_datetime-0.7.0/ and the code there doesn't include my changes from uutils/parse_datetime#103. For example, the line

    pub const YYYYMMDDHHMMSS_T_SEP_HYPHENATED_OFFSET: &str = "%Y-%m-%dT%H:%M:%S%#z";

should be in lib.rs but it isn't. Can you confirm whether that line is present or absent in your ~/.cargo/registry/src/index.crates.io-*/parse_datetime-0.7.0/src/lib.rs file?

Edit: nevermind, that's what you said 🙈 .

[jfinkels]

Ignore my previous comment. What I meant to write was this:

I checked in ~/.cargo/registry/src/index.crates.io-*/parse_datetime-0.7.0/ and the code there doesn't include my changes from uutils/parse_datetime#102. For example, the line

    pub const YYYYMMDDHHMMSS_HYPHENATED_OFFSET: &str = "%Y-%m-%d %H:%M:%S %#z";

should be in lib.rs but it isn't. Can you confirm whether that line is present or absent in your ~/.cargo/registry/src/index.crates.io-*/parse_datetime-0.7.0/src/lib.rs file?