feat: add changed_files_count predicate

policy/predicate/changed_files_count.go

@@ -0,0 +1,164 @@
+// Copyright 2018 Palantir Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package predicate
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/palantir/policy-bot/policy/common"
+	"github.com/palantir/policy-bot/pull"
+	"github.com/pkg/errors"
+)
+
+type ChangedFilesCount struct {
+	Total    ComparisonExpr              `yaml:"total,omitempty"`
+	Added    ComparisonExpr              `yaml:"added,omitempty"`
+	Modified ComparisonExpr              `yaml:"modified,omitempty"`
+	Deleted  ComparisonExpr              `yaml:"deleted,omitempty"`
+	Files    ChangedFilesCountFileFilter `yaml:"files,omitempty"`
+}
+
+type ChangedFilesCountFileFilter struct {
+	Include []common.Regexp `yaml:"include,omitempty"`
+	Exclude []common.Regexp `yaml:"exclude,omitempty"`
+}
+
+func (ff ChangedFilesCountFileFilter) IsZero() bool {
+	return len(ff.Include) == 0 && len(ff.Exclude) == 0
+}
+
+func (ff ChangedFilesCountFileFilter) MatchesFile(filename string) bool {
+	if len(ff.Exclude) > 0 && anyMatches(ff.Exclude, filename) {
+		return false
+	}
+	if len(ff.Include) > 0 && !anyMatches(ff.Include, filename) {
+		return false
+	}
+	return true
+}
+
+var _ Predicate = &ChangedFilesCount{}
+
+func (pred *ChangedFilesCount) Evaluate(ctx context.Context, prctx pull.Context) (*common.PredicateResult, error) {
+	predicateResult := common.PredicateResult{
+		ValuePhrase:     "changed files",
+		ConditionPhrase: "meet",
+		ConditionsMap:   make(map[string][]string),
+	}
+
+	files, err := prctx.ChangedFiles()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to list changed files")
+	}
+
+	// Count files by status
+	var totalCount, addedCount, modifiedCount, deletedCount int64
+	for _, f := range files {
+		if !pred.Files.MatchesFile(f.Filename) {
+			continue
+		}
+
+		totalCount++
+		switch f.Status {
+		case pull.FileAdded:
+			addedCount++
+		case pull.FileModified:
+			modifiedCount++
+		case pull.FileDeleted:
+			deletedCount++
+		}
+	}
+
+	// Add file filter information if specified
+	if len(pred.Files.Include) > 0 {
+		predicateResult.ConditionsMap["in files matching"] = getPathStrings(pred.Files.Include)
+	}
+	if len(pred.Files.Exclude) > 0 {
+		predicateResult.ConditionsMap["excluding files matching"] = getPathStrings(pred.Files.Exclude)
+	}
+
+	const conditionKey = "the file count conditions"
+
+	// Check total condition
+	if !pred.Total.IsEmpty() {
+		value := fmt.Sprintf("total %d", totalCount)
+		cond := fmt.Sprintf("total files %s", pred.Total.String())
+
+		if pred.Total.Evaluate(totalCount) {
+			predicateResult.Values = []string{value}
+			predicateResult.ConditionsMap[conditionKey] = []string{cond}
+			predicateResult.Satisfied = true
+			return &predicateResult, nil
+		}
+
+		predicateResult.Values = append(predicateResult.Values, value)
+		predicateResult.ConditionsMap[conditionKey] = append(predicateResult.ConditionsMap[conditionKey], cond)
+	}
+
+	// Check added condition
+	if !pred.Added.IsEmpty() {
+		value := fmt.Sprintf("added %d", addedCount)
+		cond := fmt.Sprintf("added files %s", pred.Added.String())
+
+		if pred.Added.Evaluate(addedCount) {
+			predicateResult.Values = []string{value}
+			predicateResult.ConditionsMap[conditionKey] = []string{cond}
+			predicateResult.Satisfied = true
+			return &predicateResult, nil
+		}
+
+		predicateResult.Values = append(predicateResult.Values, value)
+		predicateResult.ConditionsMap[conditionKey] = append(predicateResult.ConditionsMap[conditionKey], cond)
+	}
+
+	// Check modified condition
+	if !pred.Modified.IsEmpty() {
+		value := fmt.Sprintf("modified %d", modifiedCount)
+		cond := fmt.Sprintf("modified files %s", pred.Modified.String())
+
+		if pred.Modified.Evaluate(modifiedCount) {
+			predicateResult.Values = []string{value}
+			predicateResult.ConditionsMap[conditionKey] = []string{cond}
+			predicateResult.Satisfied = true
+			return &predicateResult, nil
+		}
+
+		predicateResult.Values = append(predicateResult.Values, value)
+		predicateResult.ConditionsMap[conditionKey] = append(predicateResult.ConditionsMap[conditionKey], cond)
+	}
+
+	// Check deleted condition
+	if !pred.Deleted.IsEmpty() {
+		value := fmt.Sprintf("deleted %d", deletedCount)
+		cond := fmt.Sprintf("deleted files %s", pred.Deleted.String())
+
+		if pred.Deleted.Evaluate(deletedCount) {
+			predicateResult.Values = []string{value}
+			predicateResult.ConditionsMap[conditionKey] = []string{cond}
+			predicateResult.Satisfied = true
+			return &predicateResult, nil
+		}
+
+		predicateResult.Values = append(predicateResult.Values, value)
+		predicateResult.ConditionsMap[conditionKey] = append(predicateResult.ConditionsMap[conditionKey], cond)
+	}
+
+	return &predicateResult, nil
+}
+
+func (pred *ChangedFilesCount) Trigger() common.Trigger {
+	return common.TriggerCommit
+}