1053070 - Output a nicer error when reassigning a variable in moz.build

Status: RESOLVED FIXED

(Firefox Build System :: General, defect)

Comment 1

[Mike Hommey [:glandium]]

Attachment: Output a nicer error when reassigning a variable in moz.build

Before:
mozbuild.frontend.reader.BuildReaderError: 
==============================
ERROR PROCESSING MOZBUILD FILE
==============================

The error occurred while processing the following file:

    /home/glandium/mozilla-central/moz.build

The error was triggered on line 8 of this file:

    DIRS = ['bar']

An error was encountered as part of executing the file itself. The error appears to be the fault of the script.

The error as reported by Python is:

    ['Exception: Reassigning DIRS is forbidden\n']


After:
mozbuild.frontend.reader.BuildReaderError: 
==============================
ERROR PROCESSING MOZBUILD FILE
==============================

The error occurred while processing the following file:

    /home/glandium/mozilla-central/moz.build

The error was triggered on line 8 of this file:

    DIRS = ['bar']

The underlying problem is an attempt to reassign a reserved UPPERCASE variable.

The reassigned variable causing the error is:

    DIRS

Maybe you meant "+=" instead of "="?


The message itself can probably be adjusted, but the main point was to make it a "structured" error handled at the same level as the others.

Comment 2

[Mike Hommey [:glandium]]

https://hg.mozilla.org/integration/fx-team/rev/4b87bdfaf50e

Comment 3

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/4b87bdfaf50e

Comment 4

[Jim Mathies [:jimm]]

We rely on being able to set DIST_SUBDIR to different locations in the metro code, for example:

http://mxr.mozilla.org/mozilla-central/source/browser/metro/shell/commandexecutehandler/moz.build#15
http://mxr.mozilla.org/mozilla-central/source/browser/metro/shell/linktool/moz.build#13
http://mxr.mozilla.org/mozilla-central/source/browser/metro/shell/testing/moz.build#14

what's the proper way to handle this now?

Comment 5

[Mike Hommey [:glandium]]

DIST_SUBDIR is special, this "reassignment" shouldn't trigger an error. If it does, file a bug.