Add Recipe that allows for the removal/negation of gitignore rules.

rewrite-core/src/main/java/org/openrewrite/ExcludeFileFromGitignore.java

@@ -0,0 +1,248 @@
+package org.openrewrite;
+
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.openrewrite.internal.StringUtils;
+import org.openrewrite.jgit.ignore.FastIgnoreRule;
+import org.openrewrite.jgit.ignore.IgnoreNode;
+import org.openrewrite.text.PlainText;
+import org.openrewrite.text.PlainTextVisitor;
+
+import javax.annotation.Nullable;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import static org.openrewrite.ExcludeFileFromGitignore.Repository;
+import static org.openrewrite.jgit.ignore.IgnoreNode.MatchResult.CHECK_PARENT;
+import static org.openrewrite.jgit.ignore.IgnoreNode.MatchResult.IGNORED;
+import static org.openrewrite.jgit.ignore.IgnoreNode.MatchResult.NOT_IGNORED;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class ExcludeFileFromGitignore extends ScanningRecipe<Repository> {
+
+    @Override
+    public String getDisplayName() {
+        return "Remove ignoral of files or directories in .gitignore";
+    }
+
+    @Override
+    public String getDescription() {
+        return "This recipe will remove a file or directory to the .gitignore file. " + "If the file or directory is already in the .gitignore file, it will be removed." + "If the file or directory is not in the .gitignore file, no action will be taken.";
+    }
+
+    @Option(displayName = "Paths", description = "The paths to find and remove from the gitignore files.", example = "blacklist")
+    List<String> paths;
+
+    @Override
+    public Repository getInitialValue(ExecutionContext ctx) {
+        return new Repository();
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getScanner(Repository acc) {
+        return new PlainTextVisitor<ExecutionContext>() {
+            @Override
+            public boolean isAcceptable(SourceFile sourceFile, ExecutionContext executionContext) {
+                return super.isAcceptable(sourceFile, executionContext) && sourceFile.getSourcePath().endsWith(".gitignore");
+            }
+
+            @Override
+            public PlainText visitText(PlainText text, ExecutionContext executionContext) {
+                try {
+                    String gitignoreFileName = text.getSourcePath().toString();
+                    gitignoreFileName = gitignoreFileName.startsWith("/") ? gitignoreFileName : "/" + gitignoreFileName;
+                    IgnoreNode ignoreNode = new IgnoreNode();
+                    ignoreNode.parse(gitignoreFileName, new ByteArrayInputStream(text.getText().getBytes()));
+                    acc.getRules().put(gitignoreFileName.substring(0, gitignoreFileName.lastIndexOf("/") + 1), ignoreNode);
+                    acc.issue3Directories(gitignoreFileName.substring(0, gitignoreFileName.lastIndexOf("/") + 1), text.getText());
+                } catch (IOException e) {
+                    throw new RuntimeException("Unknown error udring recipe run", e);
+                }
+                return super.visitText(text, executionContext);
+            }
+        };
+    }
+
+    @Data
+    public static class Repository {
+        private final Map<String, IgnoreNode> rules = new HashMap<>();
+        private final Map<String, List<String>> issue3IgnoredDirectories = new HashMap<>();
+        private final Map<String, List<String>> issue3NegatedDirectories = new HashMap<>();
+
+        public void exclude(String path) {
+            String normalizedPath = path.startsWith("/") ? path : "/" + path;
+            List<String> impactingFiles = rules.keySet()
+                                               .stream()
+                                               .filter(k -> normalizedPath.toLowerCase().startsWith(k.toLowerCase()))
+                                               .sorted(Comparator.comparingInt(String::length).reversed())
+                                               .collect(Collectors.toList());
+
+            IgnoreNode.MatchResult isIgnored;
+            boolean isDirectory = path.endsWith("/");
+            for (String impactingFile : impactingFiles) {
+                IgnoreNode ignoreNode = rules.get(impactingFile);
+                String nestedPath = normalizedPath.substring(impactingFile.length() - 1);
+                isIgnored = ignoreNode.isIgnored(nestedPath, isDirectory);
+                // Overcoming issue3 in jgit repo for the pathMatch being false
+                if (CHECK_PARENT.equals(isIgnored) && isDirectory) {
+                    List<FastIgnoreRule> rules = ignoreNode.getRules();
+                    for (int i = rules.size() - 1; i > -1; i--) {
+                        FastIgnoreRule rule = rules.get(i);
+                        if (rule.isMatch(nestedPath, true, false)) {
+                            if (rule.getResult()) {
+                                isIgnored = IGNORED;
+                            } else {
+                                isIgnored = NOT_IGNORED;
+                            }
+                            break;
+                        }
+                    }
+                }
+                // Overcoming issue3 in jgit repo for the single directory rules
+                if (CHECK_PARENT.equals(isIgnored)) {
+                    Boolean ignored = isIgnoredByDirectoryIssue3Bypass(impactingFile, nestedPath);
+                    if (ignored != null) {
+                        if (ignored) {
+                            isIgnored = IGNORED;
+                        } else {
+                            isIgnored = NOT_IGNORED;
+                        }
+                    }
+                }
+                if (CHECK_PARENT.equals(isIgnored)) {
+                    continue;
+                }
+                if (IGNORED.equals(isIgnored)) {
+                    List<FastIgnoreRule> remainingRules = new ArrayList<>();
+                    for (FastIgnoreRule rule : ignoreNode.getRules()) {
+                        // First 2 if clauses are for the jgit issue (#3) opened at openrewrite/jgit
+                        if (issue3IgnoredDirectories.getOrDefault(impactingFile, new ArrayList<>()).stream().anyMatch(nestedPath::equalsIgnoreCase)) {
+                            continue;
+                        } else if (issue3IgnoredDirectories.getOrDefault(impactingFile, new ArrayList<>()).stream().anyMatch(nestedPath::startsWith)) {
+                            remainingRules.add(rule);
+                            remainingRules.add(new FastIgnoreRule("!" + nestedPath));
+                            continue;
+                        } else if (!rule.isMatch(nestedPath, isDirectory, true) || !rule.getResult()) {
+                            remainingRules.add(rule);
+                            continue;
+                        } else if (rule.toString().equals(nestedPath)) {
+                            continue;
+                        } else if (rule.getNameOnly() || rule.dirOnly()) {
+                            remainingRules.add(rule);
+                            remainingRules.add(new FastIgnoreRule("!" + nestedPath));
+                            continue;
+                        }
+                        remainingRules.add(rule);
+                    }
+                    IgnoreNode replacedNode = new IgnoreNode(remainingRules);
+                    rules.put(impactingFile, replacedNode);
+                    if (CHECK_PARENT.equals(replacedNode.isIgnored(nestedPath, isDirectory))) {
+                        continue;
+                    }
+                }
+                break;
+            }
+        }
+
+        public void issue3Directories(final String gitignoreFileName, final String ignoreFile) {
+            Arrays.stream(ignoreFile.split("\\r?\\n")).forEach(line -> {
+                if (line.startsWith("#") || StringUtils.isBlank(line)) {
+                    return;
+                }
+                Map<String, List<String>> directories = issue3IgnoredDirectories;
+                if (line.startsWith("!")) {
+                    line = line.substring(1);
+                    directories = issue3NegatedDirectories;
+                }
+                if (!line.startsWith("/")) {
+                    // lines not starting with / are not exact directory matches but equivalent to **/line/
+                    return;
+                }
+                if (line.endsWith("/")) {
+                    directories.computeIfAbsent(gitignoreFileName, k -> new ArrayList<>()).add(line);
+                }
+            });
+        }
+
+        @Nullable
+        private Boolean isIgnoredByDirectoryIssue3Bypass(String gitignoreFileName, String path) {
+            List<String> ignoredDirectories = issue3IgnoredDirectories.get(gitignoreFileName);
+            List<String> negatedDirectories = issue3NegatedDirectories.get(gitignoreFileName);
+            if (negatedDirectories != null) {
+                for (String negatedDirectory : negatedDirectories) {
+                    if (path.startsWith(negatedDirectory)) {
+                        return false;
+                    }
+                }
+            }
+            if (ignoredDirectories != null) {
+                for (String ignoredDirectory : ignoredDirectories) {
+                    if (path.startsWith(ignoredDirectory)) {
+                        return true;
+                    }
+                }
+            }
+            return null;
+        }
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor(Repository acc) {
+
+        for (String path : paths) {
+            acc.exclude(path);
+        }
+
+        return new PlainTextVisitor<ExecutionContext>() {
+            @Override
+            public boolean isAcceptable(SourceFile sourceFile, ExecutionContext executionContext) {
+                return super.isAcceptable(sourceFile, executionContext) && sourceFile.getSourcePath().endsWith(".gitignore");
+            }
+
+            @Override
+            public PlainText visitText(PlainText text, ExecutionContext executionContext) {
+                String gitignoreFileName = text.getSourcePath().toString();
+                gitignoreFileName = gitignoreFileName.startsWith("/") ? gitignoreFileName : "/" + gitignoreFileName;
+                IgnoreNode ignoreNode = acc.getRules().get(gitignoreFileName.substring(0, gitignoreFileName.lastIndexOf("/") + 1));
+                if (ignoreNode != null) {
+                    String separator = text.getText().contains("\r\n") ? "\r\n" : "\n";
+                    List<FastIgnoreRule> rules = ignoreNode.getRules();
+                    List<String> newRules = Arrays.stream(text.getText().split(separator)).filter(line -> {
+                        if (line.startsWith("#") || StringUtils.isBlank(line)) {
+                            return true;
+                        }
+                        if (rules.stream().anyMatch(rule -> line.equalsIgnoreCase(rule.toString()))) {
+                            return true;
+                        }
+                        return false;
+                    }).collect(Collectors.toList());
+                    for (int i = 0; i < rules.size(); i++) {
+                        FastIgnoreRule ignoreRule = rules.get(i);
+                        if (newRules.stream().noneMatch(rule -> rule.equalsIgnoreCase(ignoreRule.toString()))) {
+                            //Can we not find the position to insert the rule using surrounding rules as best as possible?
+                            newRules.add(ignoreRule.toString());
+                        }
+                    }
+                    StringBuilder sb = new StringBuilder();
+                    for (int i = 0; i < newRules.size(); i++) {
+                        if (i > 0) {
+                            sb.append(separator);
+                        }
+                        sb.append(newRules.get(i));
+                    }
+                    return text.withText(sb.toString());
+                }
+                return super.visitText(text, executionContext);
+            }
+        };
+    }
+}