Complete slides on branching

branching/branching.tex

@@ -371,7 +371,170 @@ Deleted branch license (was 0fbe3e3).
 \end{frame}
 
 
-% todo: basic merge conflicts, tags
+\section{Basic merge conflicts}
+
+\begin{frame}
+  \frametitle{Merge conflicts}
+  Git is pretty good at merging:
+  \begin{itemize}
+    \item The changes might have been in different files.
+    \item Or in different parts of the same file.
+    \item Git tries to figure out a sensible result.
+  \end{itemize}
+  \pause
+  \bigskip
+  Sometimes this is not possible:
+  \begin{itemize}
+    \item The changes might be incompatible.
+    \item When we try \bt{git merge}, Git gives up.
+    \item This situation is called a {\em merge conflict}.
+  \end{itemize}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Setting the stage (1/3)}
+  \begin{lstlisting}
+$ git log --oneline --decorate --graph --all
+* 9d2ad27 (HEAD, master) State character preference
+| * 374ab60 (simpsons) State character preference
+|/
+* 4012f4f Initial commit
+  \end{lstlisting}
+  \bigskip
+  We'd like to merge branch \bt{simpsons} into \bt{master}.
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Setting the stage (2/3)}
+  The last commit on \bt{master}:
+  \bigskip
+  \begin{lstlisting}
+$ git show --oneline
+9d2ad27 State character preference
+diff --git a/README b/README
+index de15194..ef40359 100644
+--- a/README
++++ b/README
+@@ -1,2 +1,4 @@
+ Facts about television series
+ =============================
++
++My favorite character is Eric Cartman.
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Setting the stage (3/3)}
+  The last commit on \bt{simpsons}:
+  \bigskip
+  \begin{lstlisting}
+$ git show --oneline simpsons
+374ab60 State character preference
+diff --git a/README b/README
+index de15194..9dd729b 100644
+--- a/README
++++ b/README
+@@ -1,2 +1,4 @@
+ Facts about television series
+ =============================
++
++My favorite character is Homer Simpson.
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Creating a merge conflict}
+  \begin{lstlisting}
+$ git merge simpsons
+Auto-merging README
+CONFLICT (content): Merge conflict in README
+Automatic merge failed; fix conflicts and then
+commit the result.
+  \end{lstlisting}
+  \bigskip
+  \begin{lstlisting}
+$ git status
+# On branch master
+# Unmerged paths:
+#   (use "git add/rm <file>.." as appropriate to
+#    mark resolution)
+#
+#              both modified:      README
+#
+no changes added to commit (use "git add" and/or
+"git commit -a")
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Resolving a merge conflict (1/2)}
+  \begin{lstlisting}
+$ cat README
+Facts about television series
+=============================
+
+<<<<<<< HEAD
+My favorite character is Eric Cartman.
+=======
+My favorite character is Homer Simpson.
+>>>>>>> simpsons
+  \end{lstlisting}
+  \bigskip
+  What we had is under \bt{HEAD}, what \bt{simpsons} had is above
+  \bt{simpsons}.
+  \pause
+  \bigskip
+  \begin{lstlisting}
+$ emacs README
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Resolving a merge conflict (1/2)}
+  We resolve the conflict by hand.
+  \bigskip
+  \begin{lstlisting}
+$ cat README
+Facts about television series
+=============================
+
+My favorite characters are Eric Cartman
+and Homer Simpson.
+  \end{lstlisting}
+  \pause
+  \bigskip
+  And can now finish the merge commit.
+  \bigskip
+  \begin{lstlisting}
+$ git add README
+$ git commit
+[master 1e496cb] Merge branch 'simpsons'
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}[fragile]
+  \frametitle{Resolving conflicts with \bt{git mergetool}}
+  We can also use graphical merge tools such as {\em Meld}.
+  \bigskip
+  \begin{lstlisting}
+$ git mergetool
+merge tool candidates: meld opendiff kdiff3 ...
+Merging:
+README
+
+Normal merge conflict for 'README':
+  {local}: modified file
+  {remote}: modified file
+Hit return to start merge resolution tool (meld):
+  \end{lstlisting}
+\end{frame}
+
+\begin{frame}
+  \frametitle{Meld example}
+  \includegraphics[width=11cm]{images/meld}\\
+  \vspace{0.5cm}
+  Tools like Meld provide an editable three-way diff.
+\end{frame}
 
 
 \section{Questions?}