[ffumero2003]

Problem

b2_create_key and b2_list_keys return expirationTimestamp: null for an application key with no expiration. internal/b2types decodes it into an int64, so a null or absent value becomes 0, and base mapped it with millitime(0) = time.Unix(0, 0). Key.Expires() therefore returned 1970-01-01 with IsZero() == false, so callers couldn't tell "never expires" from "expired in 1970".

Fix

• base/base.go: a small key-specific helper, keyExpiration, maps 0 to the zero time.Time and otherwise calls millitime. CreateKey and ListKeys both use it. millitime itself is unchanged, because it also maps file upload timestamps, where 0 means something else.
• Godoc: Key.Expires() (b2) and base.Key.Expires say the zero time means the key never expires, and that callers should check IsZero(). Not Unix(), which is -62135596800 for the zero time.
• Changelog (Fixed), with the migration hint: callers comparing Expires() to 1970-01-01, or Unix() to 0, should use IsZero().

Null and absent expirationTimestamp both decode to 0 in b2types.Key, and both mean "never expires", so both map to the zero time. b2types.AuthorizeAccountResponse.KeyExpiration has the same null-to-0 pattern, but nothing reads it yet, so it's left alone.

Verification

New tests in base/key_expiration_test.go and b2/key_expiration_wire_test.go cover create and list with null, with the field absent, and with a literal timestamp (1700000000123 → 2023-11-14T22:13:20.123Z).

Break	Failing output
Restore millitime for keys	CreateKey Expires = 1969-12-31 …, want zero time (8 assertions: null and absent, create and list, base and b2)
Map every expiration to zero	CreateKey Expires = 0001-01-01 …, want 2023-11-14 22:13:20.123 +0000 UTC

With no B2 credentials set: go test -race -count=3 -shuffle=on ./..., go vet ./... and make ci pass.

Live check: the existing live tests that create a key without a lifetime now assert Expires().IsZero() on the created key and on the same key returned by ListKeys (b2/integration_test.go). They compile and run in the live CI job on main; they were not run locally (no credentials).

Other millitime callers (#244 asked to note any with the same null case): for upload, finish-large-file, copy, hide, get-file-info and unfinished-large-file timestamps, the B2 docs define no null or zero "no value" meaning. The one documented exception is virtual folder entries in delimiter listings (action: "folder", uploadTimestamp: 0), which still map to 1970. That is filed separately as #253.

make ci (tail)

go build ./...
go vet ./...
go mod tidy -diff
go mod verify
all modules verified
0 issues.
go test -race -shuffle=on ./...
ok  	github.com/Backblaze/blazer/b2	15.260s
ok  	github.com/Backblaze/blazer/b2/sync	4.724s
ok  	github.com/Backblaze/blazer/base	8.328s
ok  	github.com/Backblaze/blazer/internal/b2types	1.817s
ok  	github.com/Backblaze/blazer/internal/b2wiretest	2.345s
ok  	github.com/Backblaze/blazer/internal/blog	2.996s
ok  	github.com/Backblaze/blazer/internal/retry	2.415s
ok  	github.com/Backblaze/blazer/x/b2sim	3.563s
ok  	github.com/Backblaze/blazer/x/consistent	2.678s
ok  	github.com/Backblaze/blazer/x/transport	3.058s
ok  	github.com/Backblaze/blazer/x/window	3.393s
CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build ./...
CGO_ENABLED=0 GOOS=linux GOARCH=386 go build ./...
CGO_ENABLED=0 GOOS=linux GOARCH=arm go build ./...
CGO_ENABLED=0 GOOS=darwin GOARCH=arm64 go build ./...
CGO_ENABLED=0 GOOS=windows GOARCH=amd64 go build ./...
... scripts/*_test.sh: all ok

Closes #244

[david-santacruz-backblaze]

Looks good mate, a few small things to check before:

• Live check: could we assert key.Expires().IsZero() in an existing live test that creates a key, such as TestListBucketsWithKey? If not, a line in the PR saying that check was not run would do.
• Comment on keyExpiration: a short note on why 0 maps to the zero time and millitime is left alone would help the next reader.
• Other millitime callers: #244 asks to note any with the same null case. Could you confirm the upload timestamps can't be null?
• Nit: 5bb7db1 is titled test(...) but also touches the godoc and changelog.

[ffumero2003]

@david-santacruz-backblaze Thanks, all four:

• Live check: added (c0484e4). The existing live tests that create a key without a lifetime now assert Expires().IsZero() on the created key and on the same key returned by ListKeys. They compile; they run in the live job on main, not locally (no credentials).
• Comment on keyExpiration: added (aad79e8), explaining why 0 maps to the zero time and why millitime stays as is.
• Other millitime callers: checked. For upload, finish-large-file, copy, hide, get-file-info and unfinished-large-file timestamps, the B2 docs define no null or zero "no value" meaning. The one documented exception is virtual folder entries in delimiter listings (action: "folder", uploadTimestamp: 0), which still map to 1970. It's low impact, because Object.Attrs() re-resolves a folder by name rather than using the listing record, so it's filed separately as fix(base): virtual folder entries report a 1970 upload timestamp #253.
• Commit title nit: agreed. The squash merge uses the PR title, so 5bb7db1's title won't land on main.

The branch is synced with main, and the description now has the live-check note, the millitime audit and the make ci tail.