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Add CHANGED_TOGETHER_WITH edge for git file nodes
1 parent 765945d commit 9423311

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+90
-24
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‎cypher/GitLog/Add_CHANGED_TOGETHER_WITH_relationships_to_code_files.cypher‎

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// Take the already existing "CHANGED_TOGETHER_WITH" relationship between git files and apply it to resolved file nodes. Requires "Add_CHANGED_TOGETHER_WITH_relationships_to_git_files".
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MATCH (firstGitFile:Git&File&!Repository)-[gitChange:CHANGED_TOGETHER_WITH]-(secondGitFile:Git&File&!Repository)
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WHERE elementId(firstGitFile) < elementId(secondGitFile)
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MATCH (firstGitFile)-[:RESOLVES_TO]->(firstCodeFile:File&!Git&!Repository)
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MATCH (secondGitFile)-[:RESOLVES_TO]->(secondCodeFile:File&!Git&!Repository)
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CALL (firstCodeFile, secondCodeFile, gitChange) {
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MERGE (firstCodeFile)-[pairwiseChange:CHANGED_TOGETHER_WITH]-(secondCodeFile)
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ON CREATE SET pairwiseChange.commitCount = gitChange.commitCount
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} IN TRANSACTIONS
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RETURN count(*) AS pairCount

‎cypher/GitLog/Add_CHANGED_TOGETHER_WITH_relationships_to_git_files.cypher‎

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// Connect git files that where changed together frequently with "CHANGED_TOGETHER_WITH"
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MATCH (global_git_commit:Git:Commit)
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WITH count(global_git_commit) AS globalCommitCount
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MATCH (git_commit:Git:Commit)-[:CONTAINS_CHANGE]->(git_change:Git:Change:Update)-[:UPDATES]->(git_file:Git:File)MATCH (git_repository:Git&Repository)-[:HAS_FILE]->(git_file)
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WHERE git_file.deletedAt IS NULL
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// Order files to assure, that pairs of distinct files are grouped together (fileA, fileB) without (fileB, fileA)
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ORDER BY git_commit.sha, git_file.relativePath
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WITH globalCommitCount
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,git_commit.sha AS commitHash
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,collect(DISTINCT git_file) AS filesInCommit
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// Limit the file count to min. 2 (changed together) and
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// max. 50 (reduce permutations, improve performance, filter out large refactorings that usually affect many files)
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WHERE size(filesInCommit) >= 2
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AND size(filesInCommit) <= 50
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// Collect distinct pairwise (..., 2, 2) combinations of all files in the list
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WITH globalCommitCount
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,commitHash
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,apoc.coll.combinations(filesInCommit, 2, 2) AS fileCombinations
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UNWIND fileCombinations AS fileCombination
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WITH globalCommitCount
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,fileCombination
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,count(DISTINCT commitHash) AS commitCount
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// Filter out file pairs that where changed not very often together
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// In detail: More than 0.1 per mille compared to overall commit count
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WHERE commitCount > globalCommitCount * 0.001
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WITH fileCombination[0] AS firstFile
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,fileCombination[1] AS secondFile
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,commitCount
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// Create the new relationship "CHANGED_TOGETHER_WITH" and set the property "commitCount" on it
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CALL (firstFile, secondFile, commitCount) {
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MERGE (firstFile)-[pairwiseChange:CHANGED_TOGETHER_WITH]-(secondFile)
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ON CREATE SET pairwiseChange.commitCount = commitCount
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} IN TRANSACTIONS
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// Return one row with some statistics about the found pairs and their commit counts
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RETURN max(commitCount) AS maxCommitCount
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,avg(commitCount) AS avgCommitCount
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,percentileDisc(commitCount, 0.5) AS percentile50CommitCount
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,percentileDisc(commitCount, 0.9) AS percentile90CommitCount
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,percentileDisc(commitCount, 0.95) AS percentile95CommitCount
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,count(*) AS pairCount

‎cypher/GitLog/List_git_files_that_were_changed_together-all-in-one.cypher‎

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// List git files that where changed together frequently
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MATCH (global_git_commit:Git:Commit)
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WITH count(global_git_commit) AS globalCommitCount
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MATCH (git_commit:Git:Commit)-[:CONTAINS_CHANGE]->(git_change:Git:Change:Update)-[:UPDATES]->(git_file:Git:File)MATCH (git_repository:Git&Repository)-[:HAS_FILE]->(git_file)
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MATCH (git_repository:Git&Repository)-[:HAS_FILE]->(git_file)
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WHERE git_file.deletedAt IS NULL
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WITH *, git_repository.name + '/' + git_file.relativePath AS filePath
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WITH globalCommitCount
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,git_commit.sha AS commitHash
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,collect(DISTINCT filePath) AS filesInCommit
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WHERE size(filesInCommit) >= 2
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AND size(filesInCommit) <= 50
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WITH globalCommitCount
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,commitHash
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,apoc.coll.combinations(filesInCommit, 2, 2) AS fileCombinations
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UNWIND fileCombinations AS fileCombination
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WITH globalCommitCount
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,apoc.coll.sort(fileCombination) AS fileCombination
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,count(DISTINCT commitHash) AS commitCount
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WHERE commitCount > globalCommitCount * 0.001 // Filter out combinations that are too rare
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RETURN fileCombination[0] AS firstFile
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,fileCombination[1] AS secondFile
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,commitCount
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ORDER BY commitCount DESC

‎cypher/GitLog/List_git_files_that_were_changed_together.cypher‎

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// List git files that where changed together frequently
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// List git files that where changed together frequently. Requires "Add_CHANGED_TOGETHER_WITH_relationships_to_git_files".
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MATCH (global_git_commit:Git:Commit)
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WITH count(global_git_commit) AS globalCommitCount
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MATCH (git_commit:Git:Commit)-[:CONTAINS_CHANGE]->(git_change:Git:Change:Update)-[:UPDATES]->(git_file:Git:File)MATCH (git_repository:Git&Repository)-[:HAS_FILE]->(git_file)
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MATCH (git_repository:Git&Repository)-[:HAS_FILE]->(git_file)
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WHERE git_file.deletedAt IS NULL
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WITH *, git_repository.name + '/' + git_file.relativePath AS filePath
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WITH globalCommitCount
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,git_commit.sha AS commitHash
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,collect(DISTINCT filePath) AS filesInCommit
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WHERE size(filesInCommit) >= 2
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AND size(filesInCommit) <= 50
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WITH globalCommitCount
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,commitHash
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,apoc.coll.combinations(filesInCommit, 2, 2) AS fileCombinations
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UNWIND fileCombinations AS fileCombination
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WITH globalCommitCount
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,apoc.coll.sort(fileCombination) AS fileCombination
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,count(DISTINCT commitHash) AS commitCount
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WHERE commitCount > globalCommitCount * 0.001 // Filter out combinations that are too rare
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RETURN fileCombination[0] AS firstFile
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,fileCombination[1] AS secondFile
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,commitCount
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ORDER BY commitCount DESC
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MATCH (firstGitFile:Git&File&!Repository)-[gitChange:CHANGED_TOGETHER_WITH]-(secondGitFile:Git&File&!Repository)
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WHERE elementId(firstGitFile) < elementId(secondGitFile)
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MATCH (gitRepository:Git&Repository)-[:HAS_FILE]->(firstGitFile)
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MATCH (gitRepository:Git&Repository)-[:HAS_FILE]->(secondGitFile)
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RETURN gitRepository.name + '/' + firstGitFile.relativePath AS firstFile
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,gitRepository.name + '/' + secondGitFile.relativePath AS secondFile
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,gitChange.commitCount AS commitCount
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ORDER BY commitCount DESC

‎scripts/importGit.sh‎

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execute_cypher "${GIT_LOG_CYPHER_DIR}/Add_RESOLVES_TO_relationships_to_git_files_for_Java.cypher"
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execute_cypher "${GIT_LOG_CYPHER_DIR}/Add_RESOLVES_TO_relationships_to_git_files_for_Typescript.cypher"
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echo "importGit: Creating relationships to file nodes that where changed together..."
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execute_cypher "${GIT_LOG_CYPHER_DIR}/Add_CHANGED_TOGETHER_WITH_relationships_to_git_files.cypher"
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execute_cypher "${GIT_LOG_CYPHER_DIR}/Add_CHANGED_TOGETHER_WITH_relationships_to_code_files.cypher"
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# Since it's currently not possible to rule out ambiguity in git<->code file matching,
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# the following verifications are only an additional info in the log rather than an error.
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echo "importGit: Running verification queries for troubleshooting (non failing)..."

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