Add merge-base command

Signed-off-by: David Pordomingo <David.Pordomingo.F@gmail.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/_examples/merge_base/help-long.msg.go b/_examples/merge_base/help-long.msg.go
new file mode 100644
index 0000000..7759cbd
--- /dev/null
+++ b/_examples/merge_base/help-long.msg.go
@@ -0,0 +1,63 @@
+package main
+
+const helpLongMsg = `
+NAME:
+   %_COMMAND_NAME_% - Lists the best common ancestors of the two passed commit revisions
+
+SYNOPSIS:
+  usage: %_COMMAND_NAME_% <path> <commitRev> <commitRev>
+     or: %_COMMAND_NAME_% <path> --independent <commitRev>...
+     or: %_COMMAND_NAME_% <path> --is-ancestor <commitRev> <commitRev>
+
+ params:
+    <path>       Path to the git repository
+    <commitRev>  Git revision as supported by go-git
+
+DESCRIPTION:
+    %_COMMAND_NAME_% finds the best common ancestor(s) between two commits. One common ancestor is better than another common ancestor if the latter is an ancestor of the former.
+    A common ancestor that does not have any better common ancestor is a best common ancestor, i.e. a merge base. Note that there can be more than one merge base for a pair of commits.
+    Commits that does not share a common history has no common ancestors.
+
+OPTIONS:
+    As the most common special case, specifying only two commits on the command line means computing the merge base between the given two commits.
+    If there is no shared history between the passed commits, there won't be a merge-base, and the command will exit with status 1.
+
+--independent
+    List the subgroup from the passed commits, that cannot be reached from any other of the passed ones. In other words, it prints a minimal subset of the supplied commits with the same ancestors.
+
+--is-ancestor
+    Check if the first commit is an ancestor of the second one, and exit with status 0 if true, or with status 1 if not. Errors are signaled by a non-zero status that is not 1.
+
+DISCUSSION:
+    Given two commits A and B, %_COMMAND_NAME_% A B will output a commit which is the best common ancestor of both, what means that is reachable from both A and B through the parent relationship.
+
+    For example, with this topology:
+
+             o---o---o---o---B
+            /       /
+    ---3---2---o---1---o---A
+
+    the merge base between A and B is 1.
+
+    With the given topology 2 and 3 are also common ancestors of A and B, but they are not the best ones because they can be also reached from 1.
+
+    When the history involves cross-cross merges, there can be more than one best common ancestor for two commits. For example, with this topology:
+
+    ---1---o---A
+        \ /
+         X
+        / \
+    ---2---o---o---B
+
+    When the history involves feature branches depending on other feature branches there can be also more than one common ancestor. For example:
+
+
+           o---o---o
+          /         \
+         1---o---A   \
+        /       /     \
+    ---o---o---2---o---o---B
+
+    In both examples, both 1 and 2 are merge-bases of A and B for each situation.
+    Neither one is better than the other (both are best merge bases) because 1 cannot be reached from 2, nor the opposite.
+`