sed conditional branching with multiline section - sed

Question

I'm trying multiline replacement with sed for the first time. I found a couple of good pointers out there (general multiline help and multiline between two strings). Using this as a starter, I have the following command:
sed '
/<dependency>/,/<\/dependency>/ { # Find a set of lines for a dependency
s/\(<artifactId>\)m[^<]*\(<\/artifactId>\)/\1ARTIFACTID\2/ # Substitute if artifactId starts with 'm'
t depend-update # If we substituted, go to depend-update. Otherwise, continue
:depend-unchanged
s/\(<groupId>\)[^<]*\(<\/groupId>\)/\1CHANGE_A\2/ # Change groupId to have 'A'
b # branch to end
:depend-update
s/\(<groupId>\)[^<]*\(<\/groupId>\)/\1CHANGE_B\2/ # Change groupID to have 'B'
b # branch to end
}
' \
inputfile.xml
My input file has the following contents:
<dependency>
<groupId>foo</groupId>
<artifactId>test.a</artifactId>
</dependency>
<dependency>
<groupId>bar</groupId>
<artifactId>mytest.a</artifactId>
</dependency>
<dependency>
<groupId>baz</groupId>
<artifactId>test.b</artifactId>
</dependency>
Unfortunately, for all sections, I get "CHANGE_A". As I understand it, this means that sed always thinks that the first replace did nothing, even though it did. The result is:
<dependency>
<groupId>CHANGE_A</groupId>
<artifactId>test.a</artifactId>
</dependency>
<dependency>
<groupId>CHANGE_A</groupId>
<artifactId>ARTIFACTID</artifactId>
</dependency>
<dependency>
<groupId>CHANGE_A</groupId>
<artifactId>test.b</artifactId>
</dependency>
Where did I go wrong?

Answer 1

Multi line is due to the "problem" that sed work line by line on a strem/file input and not as a whole.
In your case you treat a pack of line but still 1 line at a time and not as a block
/startBlock/,/EndBlock/ mean just, treat all line inside those 2 delimiter, not group the block in 1 big block
Here is the adaptation proposed
sed '
/<dependency>/,\#</dependency># {
# load into the buffer
/<dependency>/ h;/<dependency>/ !H
\#</dependency># {
# At end of block, load the buffer and work on it
g
# Find a set of lines for a dependency
s/\(<artifactId>\)m[^<]*\(<\/artifactId>\)/\1ARTIFACTID\2/ # Substitute if artifactId starts with 'm'
t depend-update # If we substituted, go to depend-update. Otherwise, continue
:depend-unchanged
s/\(<groupId>\)[^<]*\(<\/groupId>\)/\1CHANGE_A\2/ # Change groupId to have 'A'
# branch to end
b # branch to end
:depend-update
s/\(<groupId>\)[^<]*\(<\/groupId>\)/\1CHANGE_B\2/ # Change groupID to have 'B'
# branch to end
b
}
}
' \
inputfile.xml