Fix touch -t with 2 digit years when YY > 68 #7378

Carreau · 2025-03-02T18:55:31Z

When using touch -t with a 2 digit year, the year is interpreted as a relative year to 2000.

When the year is 68 or less, it should be interpreted as 20xx. When the year is 69 or more, it should be interpreted as 19xx.

This is the behavior of GNU touch.

fixes gh-7280

Arguably 2 digits years should be deprecated as we are already closer to 2069, than 1969.

Carreau · 2025-03-02T18:58:20Z

I'm fairly new to rust, so I'm sure it can be improved.

Otherwise I've quite a bit of experience under my belt as a maintainer myself, so you can stay terse in your requests and explanations, I know time can be precious.

Copilot

PR Overview

This PR fixes the logic for interpreting 2-digit years in the touch command, aligning its behavior with GNU touch.

Introduces a helper function to prepend "19" or "20" to 2-digit year strings based on their value.
Updates the timestamp parsing logic to utilize the new helper function.
Adds tests to verify correct behavior for both 2-digit year ranges.

Reviewed Changes

File	Description
src/uu/touch/src/touch.rs	New helper function for determining century based on a 2-digit year is added and integrated into the timestamp parser.
tests/by-util/test_touch.rs	Added tests to confirm that 2-digit years are correctly interpreted as 20xx or 19xx based on their value.

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

src/uu/touch/src/touch.rs

tests/by-util/test_touch.rs

src/uu/touch/src/touch.rs

github-actions · 2025-03-03T16:19:55Z

GNU testsuite comparison:

Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

Carreau · 2025-03-03T18:59:00Z

One of the failure:

assertion `atime == expected` failed
  left: FileTime { seconds: -1202365696, nanos: 0 }
 right: FileTime { seconds: 3092601600, nanos: 0 }

The difference in seconds is exactly 2**32. I'm not sure why this could be.

Carreau · 2025-03-04T10:21:17Z

(workflows need approval after the recent force-push)

Carreau · 2025-03-04T12:42:09Z

for what it is worth, I think gnu touch behaviors comes from gnulib's parse-datetime.y to_tm_year(), I don't know if it should be reported as potentially problematic in 44 years.

It's unclear to me how the failure seen in uutils#7378 is related to the change in the PR, it just happen that the test need to try touching in 2068. The 2^32 error in the test makes me strongly think of the year 2038 bug, so I added a test for that.

Carreau · 2025-03-04T20:15:05Z

Failures seem to be read y2038 bug (see #7399), but I don't know if this bug should be ignored, or fixed on relevant platform, and which/if #[cfg()] to apply to the tests

RenjiSann · 2025-03-05T00:28:37Z

Failures seem to be read y2038 bug (see #7399), but I don't know if this bug should be ignored, or fixed on relevant platform, and which/if #[cfg()] to apply to the tests

#[cfg(target_pointer_width = "64")] according to Stack Overflow

github-actions · 2025-03-05T12:49:03Z

GNU testsuite comparison:

Skip an intermittent issue tests/timeout/timeout (fails in this run but passes in the 'main' branch)

It's unclear to me how the failure seen in uutils#7378 is related to the change in the PR, it just happen that the test need to try touching in 2068. The 2^32 error in the test makes me strongly think of the year 2038 bug, so I added a test for that.

When using `touch -t` with a 2 digit year, the year is interpreted as a relative year to 2000. When the year is 68 or less, it should be interpreted as 20xx. When the year is 69 or more, it should be interpreted as 19xx. This is the behavior of GNU `touch`. fixes uutilsgh-7280 Arguably 2 digits years should be deprecated as we are already closer to 2069, than 1969.

It's unclear to me how the failure seen in uutils#7378 is related to the change in the PR, it just happen that the test need to try touching in 2068. The 2^32 error in the test makes me strongly think of the year 2038 bug, so I added a test for that.

Carreau mentioned this pull request Mar 2, 2025

touch: -t YYMMDDhhmm leads to incorrect year if YY > 68 #7280

Closed

sylvestre requested a review from Copilot March 2, 2025 19:37

Copilot AI reviewed Mar 2, 2025

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