Windows: Some build steps fail with "The command line is too long"

[cwillisf]

Expected Behavior

Building scratch-blocks on Windows should succeed.

Excerpt from expected output (taken from a Linux build):

Using local compiler: google-closure-compiler ...

SUCCESS: blockly_compressed_vertical.js
Size changed from 3124 KB to 956 KB (31%).
SUCCESS: blockly_uncompressed_vertical.js
SUCCESS: blockly_uncompressed_horizontal.js
SUCCESS: blockly_compressed_horizontal.js
Size changed from 3094 KB to 945 KB (31%).
SUCCESS: blocks_compressed_horizontal.js
Size changed from 39 KB to 19 KB (49%).
blocks_vertical/vertical_extensions.js:54: WARNING - Misplaced function annotation. This JSDoc is not attached to a function node. Are you missing parentheses?
  return function() {
  ^^^^^^^^^^^^^^^^^^^

0 error(s), 1 warning(s)
SUCCESS: blocks_compressed_vertical.js
Size changed from 179 KB to 90 KB (50%).
SUCCESS: blocks_compressed.js
Size changed from 22 KB to 8 KB (37%).

Actual Behavior

The output of npm i (which internally runs python build.py among other steps) includes the message "The command line is too long" more than once. There are at least two problems here:

• Some invocations of google-closure-compiler.cmd fail because the command line is too long
• The overall build process reports success despite the failed invocations of the compiler

Excerpt from the output (note the absence of "SUCCESS" lines for blockly_compressed_vertical.js and blockly_compressed_horizontal.js):

Using local compiler: google-closure-compiler.cmd ...

The command line is too long.
UNKNOWN ERROR
The command line is too long.
UNKNOWN ERROR
SUCCESS: blockly_uncompressed_horizontal.js
SUCCESS: blockly_uncompressed_vertical.js
SUCCESS: blocks_compressed_horizontal.js
Size changed from 39 KB to 19 KB (49%).
blocks_vertical/vertical_extensions.js:54: WARNING - Misplaced function annotation. This JSDoc is not attached to a function node. Are you missing parentheses?
  return function() {
  ^^^^^^^^^^^^^^^^^^^

0 error(s), 1 warning(s)
SUCCESS: blocks_compressed_vertical.js
Size changed from 183 KB to 90 KB (49%).
SUCCESS: blocks_compressed.js
Size changed from 22 KB to 8 KB (37%).

Steps to Reproduce

1. On Windows, open a command prompt or PowerShell
   • To reproduce this issue, do not use Cygwin, MinGW, Git Bash, WSL, etc.
2. Clone the scratch-blocks repository
3. In the scratch-blocks directory, run npm i

Operating System and Browser

Windows 10 (probably any version of Windows capable of running npm)

[cwillisf]

We should fix this, but in the mean time I recommend using Cygwin or WSL to work on scratch-blocks in Windows. WSL is more reliable and is the way I do most of my work these days.

WSL setup instructions (requires Windows 10): https://docs.microsoft.com/en-us/windows/wsl/install-win10
Cygwin setup instructions: https://cygwin.com/install.html

Note that you'll need to install Python "inside" of WSL or Cygwin for this to be a complete & reliable solution. Once you have everything installed, the regular npm i should work from the WSL or Cygwin prompt.

[apple502j]

This may be due to "unnecessary" use of absolute paths in the code, although I'm not sure...

[Salik-Rafiq]

Did try the PowerShell "fix" but it doesn't fix the problem for me. It would always choose to do the remote compile - which mostly works - it's kinda hit and miss.

There is a ps1 (powershell) file but that doesn't also seem to work for me.

I guess WSL is the only way to run this process for now.

[hun9k]

Problems also occur on Git Bash.

[PhidgetsInc]

Using Windows 10, I was able to fix this by writing out the required filenames to a file and then using the hidden option --flagfile in build.py to feed in that file. See https://github.com/google/closure-compiler/blob/master/src/com/google/javascript/jscomp/CommandLineRunner.java#L695. No clue why it's a hidden option! Found that tidbit on some stackoverflow answer.

The following was done in both def gen_blocks and def gen_core in build.py, instead of line params.append(("js_file", filename)):

f = open("gen_reqfiles.txt", "w")
for filename in filenames:
# Append filenames as false arguments the step before compiling will
# either transform them into arguments for local or remote compilation
# params.append(("js_file", filename))
f.write(filename + " ")
f.close()
params.append(("flagfile", "gen_reqfiles.txt"))

(The code tag is not preserving the required Python indentation)

It was still throwing "UNKNOWN ERROR" when generating the blockly_compressed_horizontal and vertical, so I commented out line 446: #if original_b > 0 and compressed_b > 0: so that it would actually write out the file. OriginalSize was returning 0 bytes everytime, and compressed was returning ~954KB.

[NikTheGeek1]

Would using a docker container work in this case? I am getting the same error when I try to npm run prepublish using an Ubuntu container on a Windows host machine. Has anyone tried making it work with Docker?

[PaxtonPenguin]

i'm getting the error, even on wsl