Linter: Implement `html-require-script-nonce` rule by markokajzer · Pull Request #1384 · marcoroth/herb

markokajzer · 2026-03-15T18:56:35Z

closes #543

handles three things

html: <script> tags
erb: Rails javascript helpers, i.e. javascript_tag, javascript_include_tag, ~~and javascript_pack_tag~~
erb: Rails tag helpers, i.e. tag.script

uses #1374 to handle both <script> and javascript_tag helpers via BaseRuleVisitor#visitHTMLElementNode.

Note

Does not handle nil values, e.g. tag.script nonce: nil based on the specs of the inspiration. If wanted, we can add more specs and handlers.

marcoroth

Hey @markokajzer, thanks for working on this rule!

I think we want to wait for #1374, so that we can write the linter rule by just operating on HTMLElementNodes.

And then, we can probably also rename the rule to be html-* prefixed.

marcoroth · 2026-03-18T14:40:32Z

Just merged #1374 🙌🏼

markokajzer · 2026-03-18T15:32:43Z

Thank you for your tireless work @marcoroth

I'll rebase, and give it another shot! 👍

markokajzer · 2026-03-21T00:47:13Z

javascript/packages/linter/src/rules/html-require-script-nonce.ts

+
+  get defaultConfig(): FullRuleConfig {
+    return {
+      enabled: true,


just noticed it's not enabled by default in erb_lint. do we want the same here?

I think its fine to keep this one enabled for now 🙌🏼

markokajzer · 2026-03-21T00:47:21Z

javascript/packages/linter/src/rules/html-require-script-nonce.ts

+  get defaultConfig(): FullRuleConfig {
+    return {
+      enabled: true,
+      severity: "error"


what's the correct severity?

We still haven't really balanced all the severities yet. So I think we can keep this one as error for now, even though it might be a bit harsh/aggressive.

markokajzer · 2026-03-21T00:48:35Z

@marcoroth I think I got it now! Given that #1374 did not include parsing of javascript_pack_tag, I removed the handling of it here as well, so that we can simplify and only rely on visitHTMLElementNode. (I think it's also deprecated / removed in Rails as well nowadays?)

Let me know if any other changes are necessary, I wasn't sure about severity and whether we want to enable by default! 🙏

closes marcoroth#543

marcoroth

Awesome, thank you @markokajzer! I think this looks great!

Given the way the rule is structured, it should also be able to catch javascript_pack_tag once we add support for it in the parser. So I think it's fine to leave that out!

Thank you! 🙏🏼

marcoroth · 2026-03-21T01:20:21Z

javascript/packages/linter/src/rules/html-require-script-nonce.ts

+
+  get defaultConfig(): FullRuleConfig {
+    return {
+      enabled: true,


I think its fine to keep this one enabled for now 🙌🏼

marcoroth · 2026-03-21T01:22:11Z

javascript/packages/linter/src/rules/html-require-script-nonce.ts

+  get defaultConfig(): FullRuleConfig {
+    return {
+      enabled: true,
+      severity: "error"


We still haven't really balanced all the severities yet. So I think we can keep this one as error for now, even though it might be a bit harsh/aggressive.

marcoroth · 2026-03-22T02:34:50Z

Implemented a small follow up on #1452 🙌🏼

In Rails, `nonce: true` on `javascript_include_tag` and `javascript_tag` resolve to `content_security_policy_nonce` at runtime, and `nonce: false` omits the attribute. Other helpers like `tag.script` and `content_tag` pass it through as a literal value. Previously, `javascript_include_tag` and `javascript_tag` also just passed along and transformed the `nonce` value as a literal value. This pulls request adds `resolve_nonce_attribute()` to the parser to handle this transformation for `javascript_include_tag` and `javascript_tag`. So a document like: ```erb <%= javascript_tag nonce: true do %> alert('Hello') <% end %> ``` Now properly parses as: ```diff @ DocumentNode (location: (1:0)-(4:0)) └── children: (2 items) ├── @ HTMLElementNode (location: (1:0)-(3:9)) │ ├── open_tag: │ │ └── @ ERBOpenTagNode (location: (1:0)-(1:36)) │ │ ├── tag_opening: "<%=" (location: (1:0)-(1:3)) │ │ ├── content: " javascript_tag nonce: true do " (location: (1:3)-(1:34)) │ │ ├── tag_closing: "%>" (location: (1:34)-(1:36)) │ │ ├── tag_name: "script" (location: (1:4)-(1:18)) │ │ └── children: (1 item) │ │ └── @ HTMLAttributeNode (location: (1:19)-(1:30)) │ │ ├── name: │ │ │ └── @ HTMLAttributeNameNode (location: (1:19)-(1:24)) │ │ │ └── children: (1 item) │ │ │ └── @ LiteralNode (location: (1:19)-(1:24)) │ │ │ └── content: "nonce" │ │ │ │ │ ├── equals: ": " (location: (1:24)-(1:26)) │ │ └── value: │ │ └── @ HTMLAttributeValueNode (location: (1:26)-(1:30)) │ │ ├── open_quote: ∅ │ │ ├── children: (1 item) - │ │ │ └── @ LiteralNode (location: (1:26)-(1:30)) - │ │ │ └── content: "true" + │ │ │ └── @ RubyLiteralNode (location: (1:26)-(1:30)) + │ │ │ └── content: "content_security_policy_nonce" │ │ │ │ │ ├── close_quote: ∅ │ │ └── quoted: false │ │ │ ├── tag_name: "script" (location: (1:4)-(1:18)) │ ├── body: (1 item) │ │ └── @ LiteralNode (location: (1:36)-(3:0)) │ │ └── content: "\n alert('Hello')\n" │ │ │ ├── close_tag: │ │ └── @ ERBEndNode (location: (3:0)-(3:9)) │ │ ├── tag_opening: "<%" (location: (3:0)-(3:2)) │ │ ├── content: " end " (location: (3:2)-(3:7)) │ │ └── tag_closing: "%>" (location: (3:7)-(3:9)) │ │ │ ├── is_void: false │ └── element_source: "ActionView::Helpers::JavaScriptHelper#javascript_tag" │ └── @ HTMLTextNode (location: (3:9)-(4:0)) └── content: "\n" ``` So that it can get properly transformed from/to: ```erb <script nonce="<%= content_security_policy_nonce %>"> alert('Hello') </script> ``` Additionally, it updates the `html-require-script-nonce` linter rule to flag `tag.script` and `content_tag :script` using `nonce: true` or `nonce: false`, since those produce literal attribute values that will not match the CSP header. The rule now flags the following: ```erb <%= tag.script nonce: true do %> alert('Hello') <% end %> ``` with: ```txt `nonce: true` on `tag.script` outputs a literal `nonce="true"` attribute, which will not match the Content Security Policy header and the browser will block the script. Only `javascript_tag` and `javascript_include_tag` resolve `nonce: true` to the per-request `content_security_policy_nonce`. Use `javascript_tag` with `nonce: true` instead. ``` Follow up on #1384

github-actions bot added documentation Improvements or additions to documentation linter typescript linter-rule labels Mar 15, 2026

markokajzer force-pushed the marko/requirescriptnonce branch from 89a0241 to aacd635 Compare March 15, 2026 19:00

marcoroth reviewed Mar 17, 2026

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markokajzer force-pushed the marko/requirescriptnonce branch from aacd635 to 5709c8d Compare March 21, 2026 00:45

markokajzer commented Mar 21, 2026

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markokajzer requested a review from marcoroth March 21, 2026 00:47

Linter: Implement html-require-script-nonce rule

93aa945

closes marcoroth#543

markokajzer force-pushed the marko/requirescriptnonce branch from 5709c8d to 93aa945 Compare March 21, 2026 00:53

markokajzer changed the title ~~Linter: Implement erb-require-script-nonce rule~~ Linter: Implement html-require-script-nonce rule Mar 21, 2026

marcoroth approved these changes Mar 21, 2026

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marcoroth merged commit bc2eb93 into marcoroth:main Mar 21, 2026
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markokajzer mentioned this pull request Mar 21, 2026

erb-lint: NoJavascriptTagHelper #553

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marcoroth mentioned this pull request Mar 22, 2026

Parser: Properly resolve nonce: true for javascript_tag #1452

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markokajzer commented Mar 15, 2026 •

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