docs: new field of license table

docs/adrs/00009-new-field-license.md

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+# 00009. Create New Field in License
+
+Date: 2025-07-27
+
+## Status
+
+DRAFT
+
+## Context
+
+In the new license search requirements, there is a section called license summary, which requires collecting usage statistics for all licenses that appear, including how many packages and SBOMs use each license.
+
+## The Current Status of Licenses in Trustify
+
+Currently, Trustify's support for licenses is as follows:
+
+In SPDX, there are two types of licenses: licenseDeclared and licenseConcluded, and the representation is mainly in the form of license expressions, which can include custom license references (licenseRef).
+
+CycloneDX uses only one type, licenseDeclared, but offers three ways to represent it:
+
+- ID: This is a standard SPDX license ID.
+- License expression: Similar to SPDX, it supports license expressions.
+- Name: This is similar to a custom license reference, allowing for user-defined license names.
+
+In Trustify, the handling is as follows:
+
+When processing SPDX, Trustify parses the license expression into standard SPDX license IDs and exceptions, and stores them in spdx_licenses and spdx_license_exceptions. All custom license references (LicenseRef) are filtered out, while the original expression is preserved in the text field.
+
+When processing CycloneDX, there are three scenarios:
+
+- If the license is an ID, the value is saved directly in the text field and spdx_licenses.
+- If the license is a name: The value is saved directly in the text field, stores them in spdx_licenses.
+- If the license is an expression: Trustify parses it into standard SPDX license IDs and exceptions, stores them in spdx_licenses and spdx_license_exceptions, and also preserves the original expression in the text field.
+
+## The Current Issue
+
+- In SPDX, when a license expression contains a custom license ID, Trustify also saves it only in a text field, and filters out the custom license ID during the process of parsing it into standard SPDX license IDs and exceptions.
+- In SPDX, when a license expression includes a custom license ID, the custom license ID itself is meaningless and only has significance within the current SBOM, so it cannot be used for statistics or searches.
+
+## Decision
+
+Add a new field named `custom_license_refs` to the license table. Its type is a list, which includes licenses of type name appearing in CycloneDX, as well as license expressions that contain custom licenses in SPDX.
+
+```sql
+ALTER TABLE license ADD COLUMN custom_license_refs text[];
+ALTER TABLE license ADD COLUMN custom_document_license_refs text[];
+```
+### The current table structure vs. the changed table structure
+
+- Current table structure
+```rust
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel, serde::Serialize)]
+#[sea_orm(table_name = "license")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: Uuid,
+    pub text: String,
+    pub spdx_licenses: Option<Vec<String>>,
+    pub spdx_license_exceptions: Option<Vec<String>>,
+}
+```
+
+- Changed table structure
+
+```rust
+#[derive(Clone, Debug, PartialEq, Eq, DeriveEntityModel, serde::Serialize)]
+#[sea_orm(table_name = "license")]
+pub struct Model {
+    #[sea_orm(primary_key)]
+    pub id: Uuid,
+    pub text: String,
+    pub spdx_licenses: Option<Vec<String>>,
+    pub spdx_license_exceptions: Option<Vec<String>>,
+    pub custom_license_refs: Option<Vec<String>>,
+}
+```
+
+### SPDX
+
+License expression:
+
+```json
+{
+  "SPDXID": "SPDXRef-2a02a923-8a04-489d-9cbc-80f2d23de5ea",
+  "copyrightText": "NOASSERTION",
+  "downloadLocation": "https://access.redhat.com/downloads/content/package-browser",
+  "externalRefs": [
+    {
+      "referenceCategory": "PACKAGE_MANAGER",
+      "referenceLocator": "pkg:rpm/redhat/[email protected]?arch=src",
+      "referenceType": "purl"
+    }
+  ],
+  "filesAnalyzed": false,
+  "licenseConcluded": "NOASSERTION",
+  "licenseDeclared": "LicenseRef-2 AND LicenseRef-11 AND LicenseRef-BSD",
+  "name": "foreman-bootloaders-redhat",
+  "originator": "NOASSERTION",
+  "packageFileName": "foreman-bootloaders-redhat-202102220000-1.el8sat.src.rpm",
+  "supplier": "Organization: Red Hat",
+  "versionInfo": "202102220000-1.el8sat"
+}
+```
+
+Custom licenses:
+
+```json
+[
+  {
+    "comment": "External License Info is obtained from a build system which predates the SPDX specification and is not strict in accepting valid SPDX licenses.",
+    "extractedText": "The license info found in the package meta data is: GPLv2+. See the specific package info in this SPDX document or the package itself for more details.",
+    "licenseId": "LicenseRef-2",
+    "name": "GPLv2+"
+  },
+  {
+    "comment": "External License Info is obtained from a build system which predates the SPDX specification and is not strict in accepting valid SPDX licenses.",
+    "extractedText": "The license info found in the package meta data is: GPLv3+. See the specific package info in this SPDX document or the package itself for more details.",
+    "licenseId": "LicenseRef-11",
+    "name": "GPLv3+"
+  },
+  {
+    "comment": "External License Info is obtained from a build system which predates the SPDX specification and is not strict in accepting valid SPDX licenses.",
+    "extractedText": "The license info found in the package meta data is: BSD. See the specific package info in this SPDX document or the package itself for more details.",
+    "licenseId": "LicenseRef-BSD",
+    "name": "BSD"
+  }
+]
+```
+
+`custom_license_refs`: Concatenate the custom license ID and the custom license name with a colon (":").
+
+```json
+{
+  "LicenseRef-2:GPLv2+",
+  "LicenseRef-11:GPLv3+",
+  "LicenseRef-BSD:BSD",
+}
+```
+
+## Consequences
+- Positive: Enables complete license statistics and search functionality
+- Negative: Increases storage overhead and requires data migration handling
+
+## Alternatives Considered
+- Using JSONB to store complete license mappings (rejected: high query complexity)
+- Maintaining status quo without handling custom licenses (rejected: fails business requirements)
+
+## Success Metrics
+- Ability to count packages containing custom licenses
+- Support for searching by custom license ID
+
+
+## Known Issues
+
+There are two types of custom licenses:
+
+- Ones that are defined within the current SBOM, for example those with the "LicenseRef" prefix.
+- Ones that reference other SBOM documents, for example those with the "DocumentRef" prefix.
+
+Previously, we only handled the first type of custom license. The second type cannot be processed currently.
+If we want to handle the second type, we need to add a new field, `custom_document_license_refs`, to store the complete reference, such as "DocumentRef-spdx-tool-1.2:LicenseRef-BSD"[1], in this field.
+
+[1] Where "DocumentRef" is the prefix and "spdx-tool-1.2" refers to another SPDX SBOM, "LicenseRef-BSD" is the custom license reference within that SBOM.