# First git project

## 1. configuring name, email and editor

	git config --global user.name "John Doe"
	git config --global user.email "johndoe@example.com"

	# Note: if using VSCode, the "--wait" option
	# allows git to understand when you are finished
	# editing a text file
	git config --global core.editor "code --wait"

	# If you see the message:
	#     Aborting commit due to empty commit message.
	# when doing 'git commit', look up online how to use your
	# editor together with git (the message is because the
	# editor did not properly save the file before exiting).

## 2. creating a directory

	mkdir test_project

## 3. creating a git repository

	cd test_project/
	git init

## 4. creating main.c and Makefile

	# The normal/easy way is to create new files in a text editor,
	# copy/paste their content from the question, then save them in the
	# appropriate directory (test_project/main.c, test_project/Makefile)

	# Make sure that your editor uses actual TAB characters in the Makefile
	# This can be verified with 'hexdump -C Makefile': the TAB character
	# have ASCII code 9

	# If you prefer to do it from the terminal, you could use these commands to create them:
	printf '#include <stdio.h>\n\n\nint main()\n{\n\tprintf("Hello, world!\\n");\n\treturn 0;\n}\n' > main.c
	printf 'main: main.o\n\tclang -Wall -O3 -o $(@) $(^)\n\nmain.o: main.c\n\tclang -Wall -O3 -c -o $(@) $(<)\n' > Makefile

## 5. build the executable main and create .gitignore

	make

	# Preferably, we create a file containing the following lines:
	# *.o
	# /main
	# and save it as test_project/.gitignore

	# Alternatively,
	printf '*.o\n/main\n' > .gitignore

## 6. Stage

	git add -A
	git status

## 7. Commit

	git commit -m 'First commit of test_project.'


# Second git project

## 1. Clone Alice's repository

	git clone https://www.poirrier.ca/git/mathprog.git/
	cd mathprog/

## 2. Fetch and checkout Bob's commit

	git fetch https://www.poirrier.ca/git/bob.git
	git log			# does not show Bob's commit
	git log --all		# still does not show Bob's commit

	git checkout 79dcd1	# or equivalently, git checkout FETCH_HEAD
	git log			# now Bob's commit appears

	# If we want, we can already merge Bob's code into "main" now (in
	# this case, this only amounts to advancing the "main" branch
	# to Bob's commit). To do that, we would
	# git checkout main	# go back to main
	# git merge 79dcd1	# merge Bob's commit

## 3. Fetch, checkout and merge Carol's branch

	# Fetch Carol's repository
	git fetch https://www.poirrier.ca/git/carol.git
	git log			# nothing from Carol appears
	git branch		# carol_branch does not appear

	# Fetch Carol's repository (again),
	# but this time also the branch "carol_branch".
	# We call it the same locally.
	git fetch https://www.poirrier.ca/git/carol.git carol_branch:carol_branch
	git branch		# carol_branch now appears
	git checkout carol_branch
	git log
	git checkout main	# we go back to "main" to do the merge
	git log			# without --all, only ancestor commits appear
	git log --all		# with --all, we see the three commits
	git log --all --graph	# with --graph in addition, we see how they
				# relate to each other
	git merge carol_branch	# merge Carol's commit; in this case too
				# this just amounts to advancing "main"

## 4. Fix output bug

	# In the MathProg constructor, apply the following change (line 66):
	# -        if not nosolve:
	# +        if nosolve:

	git diff		# observe what you changed
	git add -A		# stage your change
	git diff --staged	# observe what is staged
				# (i.e., what you are about to commit)
	git commit -m "Fixed logic bug with nosolve parameter."


## 5. Fetch Dan's work, rebase it

	# This time for conciseness, we directly fetch "dan_branch"
	# in addition to the commits.
	git fetch https://www.poirrier.ca/git/dan.git dan_branch:dan_branch
	git log --all --graph	# we observe the divergence
				# but we decide we don't want a divergence
				# for this in our commit history, so we
				# will rebase Dan's change on top of ours
	git checkout dan_branch
	git rebase main
	git log --all --graph	# now there is no divergence
	git checkout main	# go back to main to merge "dan_branch"
	git merge dan_branch	# again, this is just advancing "main"
	git log --all --graph

## 6. Fetch Eve's work, merge it, resolve conflict

	git fetch https://www.poirrier.ca/git/eve.git eve_branch:eve_branch
	git log --all --graph	# again a divergence
	git checkout eve_branch	# we checkout Eve's branch to look at
				# her code. This time, we decide that we want
				# to keep the divergence in our commit history
	git checkout main	# we go back to main
	git merge eve_branch	# and merge Eve's branch
				# we have merge conflicts
	git status
	# Open mathprog.py, locate the conflict markers (>>>>>, <<<<<).
	# We resolve the conflicts. That is, we choose which version of the
	# conflicting lines of code we want to keep. In this case, we
	# prefer the "eve_branch" version of the code over the one in "HEAD",
	# for both conflicts.
	git add -A
	git commit