Simulating different exit code scenarios from a custom merge driver

README.md

Usage

The following scenarios can be created

Single merge base

$ ./init-repo.sh && ./run-merge.sh 0    # should successfully merge and return exit 0
$ ./init-repo.sh && ./run-merge.sh 1    # should have conflicts and return exit 1
$ ./init-repo.sh && ./run-merge.sh 129  # should fail to run internal merge and return exit 2

Multiple merge base

$ ./init-repo.sh && ./run-recursive-merge.sh 0    # should successfully merge and return exit 0
$ ./init-repo.sh && ./run-recursive-merge.sh 1    # should have conflicts and return exit 1
$ ./init-repo.sh && ./run-recursive-merge.sh 129  # should fail to run internal merge and return exit 134 for some reason?

init-repo.sh

rm -rf merge-driver-test
mkdir merge-driver-test
cd merge-driver-test
git init .
git commit --allow-empty -m "Initial"

run-merge.sh

cd merge-driver-test

echo "Setting merge driver path to $(realpath $(dirname $0))"
git config merge.custom.name "Custom merge driver"
git config merge.custom.driver "$(realpath $(dirname $0))/custom-merge-driver.sh %O %A %B %L %P"

touch .gitattributes
echo "* merge=custom" >> .gitattributes

touch custom-merge-driver.sh
echo "echo 'Hello!'" >> custom-merge-driver.sh
echo "exit $1" >> custom-merge-driver.sh
chmod +x custom-merge-driver.sh

git checkout master
echo "created on: master" > my-file.mrg
git add my-file.mrg
git commit -m"master: added my-file.mrg"

# Update 'my-file.mrg' on branch 1
git checkout -b branch-1
echo "updated on: branch-1" > my-file.mrg
git add my-file.mrg
git commit -m "branch-1: updated my-file.mrg"

# Update 'my-file.mrg' on branch 2
git checkout master
git checkout -b branch-2
echo "updated on: branch-2" > my-file.mrg
git add my-file.mrg
git commit -m "branch-2: updated my-file.mrg"

# Merge the two branches, causing a conflict
git merge -m "Merged in branch-1" branch-1

run-recursive-merge.sh

cd merge-driver-test

current_time=$(date "+%Y%m%d-%H%M%S");

branchName="branch-$current_time";
xmlFileName="sample-metadata.xml";
simpleTextFileName="sample-text.txt";

main="master";
environment="environment";
featureA="$current_time-feature-a";
featureB="$current_time-feature-b";
featureC="$current_time-feature-c";

function writeFiles() {
cat > $xmlFileName << EOM
<?xml version="1.0" encoding="UTF-8"?>
<CustomLabels xmlns="http://soap.sforce.com/2006/04/metadata">
    <labels>
        <fullName>test</fullName>
        <language>en_US</language>
        <shortDescription>$1</shortDescription>
        <protected>true</protected>
        <value>abc</value>
    </labels>
</CustomLabels>
EOM

cat > $simpleTextFileName << EOM
A heading
My favourite colour is $1.
A final line.
EOM
}

git init
git merge -abort
git checkout $main

writeFiles "BLACK"

git add --all
git commit -m "Added initial files as BLACK on main"

git branch $environment
git branch $featureA
git branch $featureB

git checkout $featureA

writeFiles "RED"

git add --all
git commit -m "Changed to RED on feature-a"

git checkout $featureB

writeFiles "BLUE"

git add --all
git commit -m "Changed to BLUE on feature-b"

git checkout $environment
git merge $featureA --commit

git checkout $environment
git merge $featureB

writeFiles "RED"

git add --all
git commit -m "Merge feature-b into environment - keep RED"

git checkout $main
git merge $featureA

git checkout $featureB
git merge $main 

writeFiles "BLUE"

git add --all
git commit -m "Merge master into feature-b - keep BLUE"

git checkout $main
git merge $featureB

git checkout $environment

cat > $xmlFileName << EOM
<?xml version="1.0" encoding="UTF-8"?>
<CustomLabels xmlns="http://soap.sforce.com/2006/04/metadata">
    <labels>
        <fullName>test</fullName>
        <language>en_US</language>
        <protected>true</protected>
        <shortDescription>RED</shortDescription>        
        <value>abc</value>
    </labels>
</CustomLabels>
EOM

cat > $simpleTextFileName << EOM
A heading
A final line.
My favourite colour is RED.
EOM

git add --all
git commit -m "Transposed lines on environment"

git checkout $main
git branch $featureC

git checkout $featureC

writeFiles "YELLOW"

git add --all
git commit -m "Changed to YELLOW on feature-c with conflicting change to env"

git checkout $environment


git config merge.custom.name "Custom merge driver"
git config merge.custom.driver "$(realpath $(dirname $0))/custom-merge-driver.sh %O %A %B %L %P"

touch .gitattributes
echo "* merge=custom" >> .gitattributes

echo "echo 'Custom merge driver is running'" >> custom-merge-driver.sh
echo "exit $1" >> custom-merge-driver.sh
chmod +x custom-merge-driver.sh

(set -x; GIT_TRACE=2 GIT_CURL_VERBOSE=2 GIT_TRACE_PERFORMANCE=2 GIT_TRACE_PACK_ACCESS=2 GIT_TRACE_PACKET=2 GIT_TRACE_PACKFILE=2 GIT_TRACE_SETUP=2 GIT_TRACE_SHALLOW=2 git merge $featureC --no-ff --no-commit)