tests/test-rhg-no-generaldelta.t
18	The idea was to: produce a large enough output that delta is always used (seq 50) have a non-linear history because I thought the bug only happens with non-linear history (I no longer believe that) make the last diff a removal at line 1, so that it cleanly applies at any revision. This means that the error is only caught by hash verification, rather than by a "lucky" index-out-of-bounds

Alphare added inline comments.Dec 8 2021, 7:10 AM

tests/test-rhg-no-generaldelta.t
18	I was very specifically talking about the `(seq.py 50; echo x) \| (read; cat) > f` part. Using `tail -n +2 f` gives you the same result while being less confusing (I think). Adding a comment saying what you're doing might be worthwhile too.

aalekseyev updated this revision to Diff 31394.Dec 8 2021, 7:36 AM

aalekseyev added inline comments.Dec 8 2021, 7:36 AM

tests/test-rhg-no-generaldelta.t
18	Oh, I started with `tail -n +2`, but I switched to `read; cat` because I thought it's more portable and cleaner. Let me clean it up further, actually, by introducing an explicit header line so we can drop it easier. (pushed a change)

aalekseyev updated this revision to Diff 31396.Dec 8 2021, 12:27 PM

The last update was to fix the issue with --pure: the output of debugdeltachain was different there.

Thanks, this is much easier to follow :)

This revision is now accepted and ready to land.Dec 10 2021, 5:52 AM

aalekseyev added a commit: rHGe33d7c39db47: rhg: demonstrate that rhg breaks on non-generaldelta revlogs.Dec 13 2021, 8:51 AM

Closed by commit rHGe33d7c39db47: rhg: demonstrate that rhg breaks on non-generaldelta revlogs (authored by aalekseyev). · Explain Why

This revision was automatically updated to reflect the committed changes.

Diff	ID	Description	Created	Lint	Unit
Base		Base
Diff 1	31362		Dec 7 2021, 1:57 PM	★	★
Diff 2	31390		Dec 8 2021, 6:25 AM	★	★
Diff 3	31394		Dec 8 2021, 7:35 AM	★	★
Diff 4	31396		Dec 8 2021, 12:27 PM	★	★
Diff 5	31451	rHGe33d7c39db472c55f51989a11d1c0078fd69aaf3	Dec 7 2021, 12:50 PM	★	★


				$ NO_FALLBACK="env RHG_ON_UNSUPPORTED=abort"

				$ cat << EOF >> $HGRCPATH
				> [format]
				> sparse-revlog = no
				> EOF

				$ hg init repo --config format.generaldelta=no --config format.usegeneraldelta=no
				$ cd repo
				$ seq.py 50 > f
				$ hg commit -q -Am initial
				$ echo x >> f
				$ hg commit -q -Am x
				$ hg update ".^"
				1 files updated, 0 files merged, 0 files removed, 0 files unresolved
				$ (seq.py 50; echo x) \| (read; cat) > f
				$ hg commit -q -Am y
				AlphareUnsubmitted Not Done This looks very complicated to not do much? I might not understand what it's trying to achieve Alphare: This looks very complicated to not do much? I might not understand what it's trying to achieve
				aalekseyevAuthorUnsubmitted Done The idea was to: produce a large enough output that delta is always used (seq 50) have a non-linear history because I thought the bug only happens with non-linear history (I no longer believe that) make the last diff a removal at line 1, so that it cleanly applies at any revision. This means that the error is only caught by hash verification, rather than by a "lucky" index-out-of-bounds aalekseyev: The idea was to: - produce a large enough output that delta is always used (seq 50) - have a…
				AlphareUnsubmitted Not Done I was very specifically talking about the `(seq.py 50; echo x) \| (read; cat) > f` part. Using `tail -n +2 f` gives you the same result while being less confusing (I think). Adding a comment saying what you're doing might be worthwhile too. Alphare: I was very specifically talking about the `(seq.py 50; echo x) \| (read; cat) > f` part. Using…
				aalekseyevAuthorUnsubmitted Done Oh, I started with `tail -n +2`, but I switched to `read; cat` because I thought it's more portable and cleaner. Let me clean it up further, actually, by introducing an explicit header line so we can drop it easier. (pushed a change) aalekseyev: Oh, I started with `tail -n +2`, but I switched to `read; cat` because I thought it's more…
				$ hg debugdeltachain f
				rev chain# chainlen prev delta size rawsize chainsize ratio lindist extradist extraratio
				0 1 1 -1 base 79 141 79 0.56028 79 0 0.00000
				1 1 2 0 prev 14 143 93 0.65035 93 0 0.00000
				2 1 3 1 prev 12 141 105 0.74468 105 0 0.00000

				rhg breaks on non-generaldelta revlogs:

				$ $NO_FALLBACK hg cat f -r . \| f --sha256 --size
				abort: corrupted revlog (rhg !)
				size=0, sha256=e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (rhg !)
				size=141, sha256=1a7fe778e33d64d5e14a9a126b77038b328356e67bacf308797bc0e39bf204f3 (no-rhg !)

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rhg: demonstrate that rhg breaks on non-generaldelta revlogs
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tests/test-rhg-no-generaldelta.t