feat(time_display): time should use /etc/timezone

[erwinvaneijk]

When a file timestamp is displayed, it should use the timezone info from the time of the timestamp, not from when it is displayed. This occurs when a file timestamp is updated under daylight saving time, and displayed at a time when not under daylight saving time.

[erwinvaneijk]

I wasn't able to fix the commit message when it was pushed to github, so created a new PR. Sorry about that.

[cafkafk]

I wasn't able to fix the commit message when it was pushed to github, so created a new PR. Sorry about that.

Does this mean this PR should be closed?

[erwinvaneijk]

No, I already closed the broken branch .

[cafkafk]

I tried to test this with libfaketime and it didn't seem to actually change the dates to DST, how did you test this?

[erwinvaneijk]

I tried to test this with libfaketime and it didn't seem to actually change the dates to DST, how did you test this?

libfaketime fakes the time of the machine, but that's not really what should be changed. It should interpret the UTC time in the timestamp to the (DST or not) timezone for the current timezone at the time of creation of the file. What I found hard is that nix apparently doesn't set the current timezone in a way that chrono_tz knows about.

I've used the following sequence to create a testcase:

% touch -d "2023-02-04 10:35:00" bar
% touch -d "2023-06-04 10:35:00" baz
% touch -d "2023-11-12 10:35:00" foo

When using ls (from GNU coreutils):

% ls -al --full-time ~/tmp/tz
-rw-r--r--  1 user staff   0 2023-02-04 10:35:00.000000000 +0100 bar
-rw-r--r--  1 user staff   0 2023-06-04 10:35:00.000000000 +0200 baz
-rw-r--r--  1 user staff   0 2023-11-12 10:35:00.000000000 +0100 foo

When using eza from main branch:

% ./target/debug/eza -l --time-style full-iso ~/tmp/tz
.rw-r--r-- 0 user 2023-02-04 10:35:00.000000000 +0100 bar
.rw-r--r-- 0 user 2023-06-04 09:35:00.000000000 +0100 baz
.rw-r--r-- 0 user 2023-11-12 10:35:00.000000000 +0100 foo

with the updated eza from PR:

% ./target/debug/eza -l --time-style full-iso ~/tmp/tz
.rw-r--r-- 0 user 2023-02-04 10:35:00.000000000 +0100 bar
.rw-r--r-- 0 user 2023-06-04 10:35:00.000000000 +0200 baz
.rw-r--r-- 0 user 2023-11-12 10:35:00.000000000 +0100 foo

And, without the updated code the test in src/output/time.rs:195 would fail.