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I am a little confused at what you've proven though!
When I compile the version that drives the ground and the version that doesn't and I have the default unused pin as weak pullup, I would expect a difference in the ttf, but it matches??
In fact I think this is the way you sent it in the zip. So I would have expected E2 to be grounded in one ttf, but weakly pulled up in the other.
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unused_pin_as_output_driving_ground.ttf and unused_pin_grounded_in_source_file.ttf are identical.
If I didn't make a mistake, that proves that driving an output pin with a hard-wired low in the source file produces exactly the same programming file as using the following .qsf setting. That was the whole point of my exercise. That means that when your programming files were different in your original post, it was because something else--probably in placement and routing--was different for those two compiles.
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set_instance_assignment -name RESERVE_PIN "AS OUTPUT DRIVING GROUND" -to unused_pin
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unused_pin_as_output_driving_ground.ttf and unused_pin_as_input_tristated.ttf are different.
I included the unused_pin_as_input_tristated.qsf revision with the next .qsf line below just so that I would have an expected .ttf difference to give me a little more confidence that the match of the other two .ttf files was a valid test.
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set_instance_assignment -name RESERVE_PIN "AS INPUT TRI-STATED" -to unused_pin
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The following .qsf line was the same for all three revisions. The following line applies only to pins that are neither in the source file nor in RESERVE_PIN settings. This line did not apply to the single unused pin that I was controlling by grounding it in the source file or by using a RESERVE_PIN setting. The RESERVE_ALL_UNUSED_PINS line made no difference in the three .ttf files--I just had to have some setting for the rest of the unused pins.
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set_global_assignment -name RESERVE_ALL_UNUSED_PINS "AS INPUT TRI-STATED WITH WEAK PULL-UP"
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Having multiple versions "running" side by side is an interesting feature.
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You compile only one revision at a time. To compile each revision, select the revision first with "Project --> Revisions".
The main uses of revisions are to evolve your .qsf settings while not losing the results of each setting combination you try or to have .qsf files with different settings for different purposes or for comparison as I did here. The Quartus revision feature does not include source file revisions, so I had to create two separate source files with and without the unused pin grounded within the source file and have each Quartus revision (each .qsf) reference the correct source file. That's where I think I made a mistake in my Cyclone III test, but I tried to be more careful for the attached test case.
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