"syntax error, unexpected keyword_rescue, expecting keyword_end" in Homebrew

I am getting Homebrew error while setting up environment for macOS. The environment setup worked just few days ago. Currently I am getting syntax error as below.

/usr/local/Homebrew/Library/Homebrew/brew.rb:23:in require_relative': /usr/local/Homebrew/Library/Homebrew/global.rb:110: syntax error, unexpected keyword_rescue, expecting keyword_end (SyntaxError) from /usr/local/Homebrew/Library/Homebrew/brew.rb:23:in

Link to the job:

Is this a TravisCI malfuntion? Does anyone gets similar issue?

The problem was caused by homebrew auto update. Disabling auto update solves the problem:


HOMEBREW_NO_AUTO_UPDATE=1 brew install qt5 ninja


Thanks for the solution.

Same applies for brew tap and brew tap-pin:

  • HOMEBREW_NO_AUTO_UPDATE=1 brew tap cartr/qt4
  • HOMEBREW_NO_AUTO_UPDATE=1 brew tap-pin cartr/qt4
  • HOMEBREW_NO_AUTO_UPDATE=1 brew install qt@4

This is a bug in Homebrew that was fixed in https://github.com/Homebrew/brew/commit/00dbb221b7c125073957ca51d2341adc11f6aafc (1.9.0). It happens on Homebrew autoupdate: the post-update invocation still uses the old environment (in this particular situation, the old Ruby version). It surfaced since https://github.com/Homebrew/brew/commit/341ea6080716cb06c83fb8a232f2f5929700c1a0 which added Ruby 2.5+ exclusive syntax.

Travis staff need to update Homebrew in affected images. @BanzaiMan @dominic

A workaround is to either

  • disable autoupdate with HOMEBREW_NO_AUTO_UPDATE=1 <command> or export HOMEBREW_NO_AUTO_UPDATE=1 as mentioned before, or
  • run brew update manually before other brew commands
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