appview/validator: write validators for pull records

Signed-off-by: oppiliappan <[e-mail]>

appview/validator/pull.go

···
+package validator
+
+import (
+	"database/sql"
+	"fmt"
+	"strings"
+
+	"tangled.org/core/appview/db"
+	"tangled.org/core/appview/models"
+	"tangled.org/core/orm"
+	"tangled.org/core/patchutil"
+)
+
+func (v *Validator) ValidatePull(pull *models.Pull) error {
+	if len(pull.Submissions) == 0 {
+		return fmt.Errorf("pull must have at least one submission")
+	}
+
+	latestSubmission := pull.LatestSubmission()
+	if latestSubmission == nil {
+		return fmt.Errorf("pull must have a valid latest submission")
+	}
+
+	isFormatPatch := patchutil.IsFormatPatch(latestSubmission.Patch)
+
+	// title and body can only be empty if the patch is a format-patch
+	if !isFormatPatch {
+		if pull.Title == "" {
+			return fmt.Errorf("pull title is empty (required for non-format-patch pulls)")
+		}
+
+		if pull.Body == "" {
+			return fmt.Errorf("pull body is empty (required for non-format-patch pulls)")
+		}
+
+		if st := strings.TrimSpace(v.sanitizer.SanitizeDescription(pull.Title)); st == "" {
+			return fmt.Errorf("title is empty after HTML sanitization")
+		}
+
+		if sb := strings.TrimSpace(v.sanitizer.SanitizeDefault(pull.Body)); sb == "" {
+			return fmt.Errorf("body is empty after HTML sanitization")
+		}
+	}
+
+	// the dependent_on should not form a DAG, aka, two PRs should not have the same dependent
+	if pull.DependentOn != nil {
+		dependentPull, err := db.GetPull(
+			v.db,
+			orm.FilterEq("dependent_on", pull.DependentOn.String()),
+		)
+
+		if err == sql.ErrNoRows {
+			return nil
+		}
+
+		if err != nil {
+			return fmt.Errorf("failed to fetch pulls with same dependency: %w", err)
+		}
+
+		if dependentPull.AtUri() == pull.AtUri() {
+			return nil
+		}
+
+		return fmt.Errorf("another pull already depends on %s, which would form a DAG, this is presently disallowed", pull.DependentOn.String())
+	}
+
+	return nil
+}