User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.119 Safari/537.36

Steps to reproduce:

I am trying to build Firefox to run Mochitests for Mozilla's debugger.html.

I went through the following steps in the debugger directory. Homebrew and Python are already installed:

brew install mercurial
brew install autoconf@2.13 && brew unlink autoconf
./bin/prepare-mochitests-dev

Actual results:

When I run the final step ./bin/prepare-mochitests-dev,
a few errors occur.
After adding file changes, I see the error "abort: Connection reset by peer."
Then I see the following error:

fs.js:115
throw err;
^

Error: ENOENT: no such file or directory, open '/Users/MacUser/Documents/debugger/firefox/devtools/client/shared/vendor/WasmParser.js'
at Object.openSync (fs.js:439:3)
at Object.writeFileSync (fs.js:1190:35)
at copyWithReplace (/Users/MacUser/Documents/debugger/bin/copy-assets.js:158:6)
at copyWasmParser (/Users/MacUser/Documents/debugger/bin/copy-assets.js:163:3)
at start (/Users/MacUser/Documents/debugger/bin/copy-assets.js:281:3)
at Object.<anonymous> (/Users/MacUser/Documents/debugger/bin/copy-assets.js:358:3)
at Module._compile (internal/modules/cjs/loader.js:689:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
at Module.load (internal/modules/cjs/loader.js:599:32)
at tryModuleLoad (internal/modules/cjs/loader.js:538:12)

I then try to run the Mochitests in the debugger directory:

yarn copy
./firefox/mach build

I get the error:
[copy-assets] copy tests
[copy-assets] copy wasm parser
{ Error: ENOENT: no such file or directory, open '/Users/MacUser/Documents/debugger/firefox/devtools/client/shared/vendor/WasmParser.js'
at Object.openSync (fs.js:439:3)
at Object.writeFileSync (fs.js:1190:35)
at copyWithReplace (/Users/MacUser/Documents/debugger/bin/copy-assets.js:158:6)
at copyWasmParser (/Users/MacUser/Documents/debugger/bin/copy-assets.js:163:3)
at start (/Users/MacUser/Documents/debugger/bin/copy-assets.js:281:3)
at module.exports (/Users/MacUser/Documents/debugger/bin/copy-assets.js:365:12)
at copy (/Users/MacUser/Documents/debugger/bin/copy.js:41:13)
at start (/Users/MacUser/Documents/debugger/bin/copy.js:60:10)
at Object.<anonymous> (/Users/MacUser/Documents/debugger/bin/copy.js:117:3)
at Module._compile (internal/modules/cjs/loader.js:689:30)
errno: -2,
syscall: 'open',
code: 'ENOENT',
path:
'/Users/MacUser/Documents/debugger/firefox/devtools/client/shared/vendor/WasmParser.js' }
It looks like you are missing some files. The mozilla-central codebase may be missing at ${mc}. You can clone mozilla-central by running ./bin/prepare-mochitests-dev from the root of the debugger.html repository. You can find more information on bundling or mochitests at https://github.com/firefox-devtools/debugger/blob/master/docs/bundling.md or https://github.com/firefox-devtools/debugger/blob/master/docs/mochitests.md
✨ Done in 2.72s.

Expected results:

The Firefox build should download with no errors and I should be able to run Mochitests.
I also noticed that the folders beginning with /shared in the error message do not exist in the directory:

/Users/MacUser/Documents/debugger/firefox/devtools/client/shared/vendor/WasmParser.js'

The folder structure is entirely different from what the program seems to be searching for.

I should also mention that I asked a few other developers to try this on their machines and it did work for them without errors. I am not sure how to isolate the issue causing my particular machine to throw errors, but any help would be greatly appreciated.

Please change if this is not the right component!

Hi Jason, I saw your name associated with the docs linked in comment 0, is there a DevTools component that would be more appropriate for this report?

Hello Miriam! I've also seen this WasmParser.js issue in the past and we've not updated the script recently. Sometimes a second run of the scrip fixes the issue.

Essentially what the script is doing is cloning Firefox down from mozilla central into a ./firefox directory within the debugger. You can go to your local debugger checkout and run:

hg clone https://hg.mozilla.org/mozilla-central ./firefox

You can then go to that directory and build Firefox:

cd ./firefox
./mach bootstrap
./mach build

To see run tests, you can do the following from the debugger directory:

yarn copy
./firefox/mach build
yarn mochid browser_dbg-{test-name}

Let me know if you have questions and please feel free to ping us in the #debugger channel on Slack!