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Up-to-date

Node.js Collaborator Summit 2018-10-12

Yang Guo Google/V8 @hashseed @v8js

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Agenda

Release schedules

Versions

ABI stability

Deprecation policy

Bisection

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Prague astronomical clock, source: wikipedia.org

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Chromium release schedule

Current tip-of-tree version: 71

Every 6 weeks:

  • current_version++
  • beta_version = current_version - 1
  • stable_version = beta_version - 1

Code committed today reaches

  • Canary channel within a day
  • Dev channel within a week
  • Beta channel within 6 weeks
  • Stable channel in 6-12 weeks

​

​

Source: www.chromium.org/getting-involved/dev-channel� www.chromium.org/developers/calendar

@v8js

@hashseed

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V8 release schedule

Current tip-of-tree version: 7.1

Version bump and new branch every 6 weeks

Version X.Y corresponds to Chrome XY�(no semantic versioning)

Autoroll several times per day�(updating Chrome with new V8 version)

API freeze 7 days before branch

Continuously tested against Node.js and Chromium

Maintained until next branch is promoted to stable

Source: github.com/v8/v8/wiki/Release-Process

@v8js

@hashseed

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V8 release schedule

6 weeks

branch point

stable

stable

beta

stable

current (master)

current (master)

beta

beta

current (master)

backmerges

@v8js

@hashseed

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Backmerges of V8 commits

V8

✓ stable and beta branches

✓ security fixes

✓ stability fixes

✗ performance improvements

✗ new features

✗ API changes

Node

✓ master and LTS branches

✓ security fixes

✓ stability fixes

✓ performance improvements

✗ new features

✗ API changes

✓ API reverts

“Float” patches downstream

Source: github.com/nodejs/node/issues/19354#issuecomment-373157341

@v8js

@hashseed

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V8 version

node -e "console.log(process.versions.v8)"

7.0.276.24-node.5

​

not semver

@v8js

@hashseed

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V8 version

node -e "console.log(process.versions.v8)"

7.0.276.24-node.5

V8 version

Build number

Patch level

Embedder string

@v8js

@hashseed

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Node release schedule

Node.js master

  • https://github.com/nodejs/node/tree/master
  • development branch
  • updates to latest stable V8 release

​

Node.js canary

  • https://github.com/nodejs/node-v8/tree/canary
  • maintained by @targos
  • daily builds with current V8
  • simplifies updating master

@v8js

@hashseed

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Node release schedule

vee-eight-lkgr

  • https://github.com/v8/node/tree/vee-eight-lkgr
  • lkgr = last-known good revision
  • fork maintained by the V8 team
  • infrequently syncs with upstream master
  • used for integration test and commit queue
  • does not update gyp
  • floating fixes

@v8js

@hashseed

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Node release schedule

LTS branch

  • currently: 10
  • once a year
  • initial release April
  • LTS from October
  • 3 year lifetime

​

non-LTS branch

  • currently: 11
  • once a year in October

​

Source: github.com/nodejs/Release

@v8js

@hashseed

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V8 in Node 10

Node 10

initial release Apr. 24

LTS promotion Oct.

​

​

V8

6.5 Mar. 06

6.6 Apr. 17

6.7 May 29

6.8 July 24

6.9 Sep. 04

7.0 Oct. 16

Source: github.com/nodejs/node/issues/19354#issuecomment-373157341

@v8js

@hashseed

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Compatibility table, source: astrology-zodiac-signs.com

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ABI stability

API compatibility = can compile

ABI compatibility = can link

✓ add new API

✓ append enum element

✗ remove/rename API

✗ add optional function parameter

✗ reorder enum, change constant value

✗ change inline implementation in the header

​

@v8js

@hashseed

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ABI stability

Node.js

  • same version guarantees ABI stability to addons
  • exposes v8.h directly
  • ⇒ same version can only upgrade to ABI-compatible V8

For Node 10

  • API for 6.7 is frozen at initial release
  • initially release 6.6 w/ forward compat patch
  • after 6 weeks 6.7 w/o patch
  • Another 6 weeks 6.8 w/ backward compat patch
  • @psmarshall and @targos

Source: github.com/nodejs/node/issues/19354#issuecomment-373157341

@v8js

@hashseed

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V8 in Node 10

Node 10

initial release Apr. 24

LTS promotion Oct.

​

​

V8

6.5 Mar. 06

6.6 Apr. 17

6.7 May 29

6.8 July 24

6.9 Sep. 04

7.0 Oct. 16

Source: github.com/nodejs/node/issues/19354#issuecomment-373157341

@v8js

@hashseed

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Deprecation policy

V8

  • Mark as V8_DEPRECATED_SOON
  • Remove uses in Chrome and V8
  • Mark as V8_DEPRECATED
  • Wait at least 1 version bump (6 weeks)
  • Remove

Node.js

  • Mark as deprecated
  • Wait at least 1 version bump (6 months)
  • Remove

​

Source: bit.ly/2OD9HFY

@v8js

@hashseed

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Bisection, in a nutshell

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Bisection

Node 8 .. Node 10 ~3600 commits

V8 6.2 .. V8 6.8 ~5800 commits

​

  • Try to find pure JavaScript repro for d8
  • Bisection with Node.js is more involved
  • Patience

​

@v8js

@hashseed

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Bisection in V8

Start bisection

git bisect start

Test current revision

gclient sync�tools/dev/gm.py x64.release.d8�out/x64.release/d8 -e "console.log(BigInt === undefined)"�false�git bisect bad

Choose candidate and test again. Rinse and repeat

git checkout branch-heads/6.5�gclient sync�tools/dev/gm.py x64.release.d8�out.gn/x64.release/d8 -e "console.log(BigInt === undefined)"�true�git bisect good

@v8js

@hashseed

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Bisection in Node.js

Bisected to

commit 6a31d05340b22fc413ee83eaacd0a5565bbbe799�Author: Michaël Zasso <[email protected]>�Date: Wed Jul 25 19:30:07 2018 +0200�� deps: update V8 to 6.8.275.24�� PR-URL: https://github.com/nodejs/node/pull/21079� Reviewed-By: James M Snell <[email protected]>� Reviewed-By: Matteo Collina <[email protected]>� Reviewed-By: Colin Ihrig <[email protected]>� Reviewed-By: Yang Guo <[email protected]>

​

Now what?

​

@v8js

@hashseed

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Finding V8 commit range

git diff 6a31d05340b^ 6a31d05340b deps/v8/include/v8-version.h��diff --git a/deps/v8/include/v8-version.h b/deps/v8/include/v8-version.h�index 09c47d7e91..e57efc3084 100644�--- a/deps/v8/include/v8-version.h�+++ b/deps/v8/include/v8-version.h�@@ -9,9 +9,9 @@� // NOTE these macros are used by some of the tool scripts and the build� // system so their names cannot be changed without changing the scripts.� #define V8_MAJOR_VERSION 6�-#define V8_MINOR_VERSION 7�-#define V8_BUILD_NUMBER 288�-#define V8_PATCH_LEVEL 49�+#define V8_MINOR_VERSION 8�+#define V8_BUILD_NUMBER 275�+#define V8_PATCH_LEVEL 24

​

​

Source: https://github.com/v8/v8/wiki/Using-Git

@v8js

@hashseed

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Bisect in V8, test in Node.js

Set bisection range

cd path/to/v8�git checkout 6.7.288.49�git bisect start�git bisect bad�git checkout 6.8.275.24�git bisect good

Update Node.js with V8

tools/node/update_node.py . path/to/node --gclient

Build Node.js (and hope API did not change)

cd path/to/node�./configure --build-v8-with-gn # to not rely on up-to-date gyp configs�make -j4 node

@v8js

@hashseed

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New Chrome and V8 release every 6 weeks

New Node.js release every 6 months

​

​

V8 is updated between initial release and LTS promotion ABI needs to stay stable

​

​

Bisection is easier if the repro does not rely on Node.js

​

​

Reach out: @hashseed