Bug 55702 - Minor difference in generated .pdb file size from msbuild relative to xbuild
Summary: Minor difference in generated .pdb file size from msbuild relative to xbuild
Alias: None
Product: Tools
Classification: Mono
Component: msbuild ()
Version: 5.0 (2017-02)
Hardware: PC Mac OS
: --- normal
Target Milestone: Future Cycle (TBD)
Assignee: Marek Safar
Depends on:
Reported: 2017-04-27 21:25 UTC by Kyle White
Modified: 2017-09-13 20:11 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Kyle White 2017-04-27 21:25:36 UTC
We aren't sure if this is really an issue yet but after discussing with Ankit and Marek it might be worth investigating. I have an assembly where I can reproduce a very small (4 byte) difference in the the generated .pdb file.

Steps to reproduce:
1) grab this project https://codeload.github.com/colbylwilliams/XWeather/zip/master
2) cd to the XWeather directory 
3) restore nugets
4) run msbuild/xbuild (default targets)

I did this twice in two separate directory (one for xbuild and the msbuild) to ensure no artifacts left behind or anything. 

I generated a diff of the two directories after the builds and discovered XWeather.UITests.pdb which has the minor size difference. Here you can see the directory diff:  http://xqa.blob.core.windows.net/gist/Xweather-artifact-compare.zip-5311e0b6001f46288eecc823fb0e4ace.zip (just unzip and open Report.html)

Microsoft (R) Build Engine version (xplat-2017-02/20b9fb5 Fri Apr 21 18:42:23 EDT 2017)
Comment 1 Kyle White 2017-05-01 15:31:08 UTC
This can be reproduced regularly across various samples it seems. I see the same behavior in the following two samples:

Repo: https://github.com/xamarin/Sport
Diff: http://xqa.blob.core.windows.net/gist/Sport-mobile-artifact-compare.zip-f443b35e2e374a7f934643e975888978.zip

Repo: https://github.com/jamesmontemagno/MyShoppe
Diff: http://xqa.blob.core.windows.net/gist/MyShoppe-artifact-compare.zip-c5d82487c9c44284914f09d9b9fbaf26.zip
Comment 2 Brendan Zagaeski (Xamarin Team, assistant) 2017-07-05 20:15:06 UTC
Unfortunately this curious little difference in the .pdb file has not yet been investigated on the now-frozen 15.3 target milestone, so I will move the bug to the next upcoming milestone for an initial engineering review.
Comment 3 Marek Safar 2017-09-11 17:06:36 UTC
I cannot reproduce the issue locally with 

Visual Studio Community 2017 for Mac (Preview)
Version 7.2 Preview (7.2 build 583)
	Mono (2017-06/1afb931de69) (64-bit)

Both msbuild and xbuild produce XWeather.UITests.pdb with the size of 2768. You need to use the same folder for the files as the path is encoded in the PDB file.
Comment 4 Kyle White 2017-09-13 20:11:40 UTC
I think we can close this, the difference is likely due to the different path used as noted in comment 3