"gn gen" Isn't Working

[jord...@google.com]

I started working in the Chromium codebase for the first time in months starting a couple weeks ago in order to bisect some settings regressions. I've been experiencing a ton of problems with building/syncing etc., especially when I'm looking at old checkouts. I deleted and reinstalled Chromium a couple times when I got in very strange states

My issue now is that when I run my standard "gn gen" for building linux-cros, i.e.

$ gn gen out/Default --args="target_os = \"chromeos\" use_goma=true"

I get on the following error:

ERROR at //build/config/jumbo.gni:104:3: Unknown function.

  not_needed([ "gen_target_dir" ])  # Prevent "unused variable".

I tried commenting it out, but every time I commented something out and ran my command, I would get a new (but similar) failure.

jamescook@ pointed out that by gn binary doesn't seem to be updating properly and the output of

$ gn --version

on my workstation is "465654", while other everyone else I've talked to has something following the pattern 14[0-9]{2} \([a-z0-9]{8}\)

[Christian Biesinger]

Is your depot_tools up to date? (E.g. try "git log" in depot_tools, or
"git pull --rebase")

Christian

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[Jordy Greenblatt]

Yes, I cloned them today.

[Christian Biesinger]

And gclient runhooks succeeds?

Christian

[Jordy Greenblatt]

Yes:

jordynass@jordynass:~/chromium/src$ gclient runhooks

Running hooks: 100% (77/77), done.                                

+===================================================+

|   METRICS COLLECTION WILL START IN 7 EXECUTIONS   |

|                                                   |

| To suppress this message opt in or out using:     |

| $ gclient metrics [--opt-in] [--opt-out]          |

| For more information please see metrics.README.md |

| in your depot_tools checkout or visit             |

| https://goo.gl/yNpRDV.                            |

+===================================================+

jordynass@jordynass:~/chromium/src$ 

[Christian Biesinger]

Do you have ./buildtools/linux64/gn (adjust for platform as necessary)
in the src/ directory, and if yes is it the current version?

(Maybe try deleting it and re-running hooks?)

Christian

[Dirk Pranke]

Please see my response to the other thread, too. Sorry, I didn't realize there were two threads on this topic :(.

-- Dirk

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/CAPTJ0XGMnC_Y3orpPU3JbQhEaXiPgDHXTSj%3DpFTYkM%3DwLqopVA%40mail.gmail.com.

[Nico Weber]

Also see https://groups.google.com/a/chromium.org/forum/#!searchin/chromium-dev/buildtools$20thomasanderson%7Csort:date/chromium-dev/62fSQNzVfyg/01AefvtlGAAJ ; people syncing across ~ Feb 7 2019 might hit this.

To view this discussion on the web visit https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/CAEoffTBa3dQEUoWmZ0Q80PjEqkND5HijeXa%2BxXjL60Yp%2B2tdSQ%40mail.gmail.com.

[Dirk Pranke]

The syncing-across-buildtools issue is similar, but not directly the same problem.

Recently (r641353 from Mar 15) I switched GN from being installed via a gclient hook that downloaded a binary from a Google Cloud Storage Bucket to installing via CIPD (the current mechanism we encourage people to use to install versions of binary packages).

Unfortunately, as it turns out, we chose to install the CIPD version into the same location the old binary was, and that means that if you happen to sync back to an old enough version of the code to get an older GN (older than 4 months ago, because that's how long it's been since we actually rolled GN, even though we changed how we pull it in as thakis says), then the  hook would copy the old binary on top of the CIPD binary, but the CIPD package manager didn't realize that, and so it thinks the version is up to date when it isn't.

And, it looks like that's what Jordy was doing. 

In the meantime, if you think you're hitting something like this, the workaround is to run `rm -fr buildtools/linux64/{.versions,gn} && gclient sync` to force cipd to reinstall things.

I've filed crbug.com/944367 to work on a fix.

-- Dirk

[Jordy Greenblatt]

Thank you very much, Dirk. I can confirm that I just successfully build a Chromium commit from yesterday (6dc4886cc880fb21e4046f4af5c95a82091c358c) and open virtual CrOS on my workspace, which I was unable to do before running 'rm -fr buildtools/linux64/{.versions,gn} && gclient sync'.