refactor(compartment-mapper): use @endo/errors by erights · Pull Request #3152 · endojs/endo

erights · 2026-03-31T01:14:22Z

Closes: #XXXX
Refs: 3fcb5b1#diff-2ce5fb201c10cb24e075359132ab825315f08bdd168d4c8e9ff464b87d3e74ffR4-R7 , #3110

Description

@boneskull reminded me of 3fcb5b1#diff-2ce5fb201c10cb24e075359132ab825315f08bdd168d4c8e9ff464b87d3e74ffR4-R7

This PR moves from the assert style towards the

    expr || Fail`...`

style, which is more efficient in the typical non-erroneous case, and is more idiomatic for Endo. It does this at the price of introducing a new dependency from @endo/compartment-mapper to @endo/error . If it is important for @endo/compartment-mapper not to transitively depend on ses, then this PR should probably wait on #3110 or a successor that accomplishes the same goal.

Security Considerations

None

Scaling Considerations

If this PR waits for #3110 or equivalent, then none. Otherwise, the transitive dependency on ses may be significant. OTOH, @endo/compartment-mapper's use of ses's assert shows that it is already transitively dependent, so probably makes no difference either way.

Documentation Considerations

We want to encourage the ... || Fail... style over the assert style, so good to get rid of violations of our own style preferences in our own code.

Testing Considerations

All existing tests pass without modification, which should be good enough for this refactoring PR.

Compatibility Considerations

Some error messages that were formed with untagged template literals are now formed with Fail. Untagged template literals don't redact, which seems to be intentional here. To preserve that intention, this PR annotations all Fail interpolations that did not already have a q(...) with a b(...).

Upgrade Considerations

none

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boneskull

So while I don't have a major problem with landing this, I'll likely change it later once we land support for Error.code; I want all exceptions thrown (directly) out of @endo/compartment-mapper to have a proper error code.

Please let the record show I didn't ask for an implementation. 😉 Mostly I was curious about whether I needed to use details/X anywhere, and how. I should have been more specific. That said, I don't even know when to use b/bare, so I'm hoping you can enlighten me.

The reason behind the original ask was that I'm also looking into partitioning the assertions here into this module for CompartmentMapDescriptor-specific assertions and another for general, reusable assertions (e.g., assertPlainObject, assertFileUrlString), with an eye towards enabling PackageCompartmentMapDescriptor validation before returning from mapNodeModules. I saw the TODO and didn't want to propagate the same problem to a new module.

boneskull · 2026-03-31T19:56:58Z

@@ -1,5 +1,6 @@
 /* Validates a compartment map against its schema. */

+import { Fail, q, b } from '@endo/errors';


I don't understand why we're pulling in @endo/errors if all these symbols are already available in globalThis. I'm missing some context.

We’re moving toward importing these global facilities from a package mostly because it’s easier to thread types, but in the long run, @endo/errors will become usable without first importing ses.

boneskull · 2026-03-31T20:01:20Z

+  typeof value === 'string' ||
+    Fail`${b(pathOrMessage)} in ${q(url)} must be a string; got ${q(value)}`;


As I noted in Slack, I am not fond of Fail generally for two reasons:

It cannot support Error.code

When used outside of an asserts type guard, TS cannot infer that Fail terminates unless throw is used. This makes correct usage of Fail rather tricky.

We could mitigate 1. by introducing a Fail.code(str)-like API, but that's very much a separate PR & discussion.

I have a branch where I've replaced all thrown errors (including usage of Fail, throw new Error(), & throw Error()) with a wrapper using makeError(), built on top of #3130. While this would be fine to merge as-is, I would want to replace the Fail calls (regardless of whether Fail.code() becomes a thing).

boneskull · 2026-03-31T20:02:36Z

 * @param {string} keypath
 * @param {string} url
- * @returns {asserts alleged is string}
+ * @returns {asserts allegedLabel is string}


boneskull · 2026-03-31T20:03:46Z

+  /^(?:@[a-z][a-z0-9-.]*\/)?[a-z][a-z0-9-.]*(?:>(?:@[a-z][a-z0-9-.]*\/)?[a-z][a-z0-9-.]*)*$/.test(
+    allegedLabel,
+  ) ||
+    Fail`${b(keypath)} must be a canonical name in ${q(url)}; got ${q(allegedLabel)}`;


I am a little unclear on where we want to use b/bare vs q/quote; obviously the latter is for strings, but from what I can tell, keypath is also a string.

…irror Three findings from the PR 114 dispatch (mirror of endojs/endo#3152): 1. Working-mirror dispatch is distinct from the strict review-only mirror. The constraints in pr-mirror-for-offline-review.md (no commit modification, no feedback addressing) apply only to the review-only shape. The working-mirror shape opens a real iterating PR; follow-up commits land on top of the upstream tip and are cherry-picked back upstream when the maintainer accepts. 2. CI may not auto-fire on a mirror branch whose head SHA is inherited from an upstream commit the bot fork has never seen. The local pre-PR checklist becomes the load-bearing CI substitute, not just a convenience. Symptom: gh pr checks reports no checks; check-suites shows only renovate and claude apps queued; workflow runs endpoint returns total_count: 0. 3. The bot mirror's master can be ahead AND behind upstream's master simultaneously: design-only PRs live in the bot fork while upstream commits accumulate; disclose both directions of the lag in the PR body, not just one. Sibling section added to skills/pr-mirror-for-offline-review.md pointing at the working-mirror posture in roles/builder.md, plus a PR 114 entry in the session-example list.

kriskowal · 2026-05-07T23:00:10Z

@@ -1,5 +1,6 @@
 /* Validates a compartment map against its schema. */

+import { Fail, q, b } from '@endo/errors';


We’re moving toward importing these global facilities from a package mostly because it’s easier to thread types, but in the long run, @endo/errors will become usable without first importing ses.

erights self-assigned this Mar 31, 2026

erights requested a review from boneskull March 31, 2026 01:16

erights marked this pull request as ready for review March 31, 2026 01:31

erights requested a review from kriskowal March 31, 2026 01:32

boneskull approved these changes Mar 31, 2026

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This was referenced May 7, 2026

refactor(compartment-mapper): use @endo/errors [mirror of endojs/endo#3152] endojs/endo-but-for-bots#114

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Review priority focus endojs/endo-but-for-bots#120

Closed

refactor(compartment-mapper): use @endo/errors

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kriskowal force-pushed the markm-compartment-mapper-errors branch from a8f1243 to 0ef87dd Compare May 7, 2026 22:59

kriskowal approved these changes May 7, 2026

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kriskowal enabled auto-merge May 7, 2026 23:02

kriskowal merged commit c513f1a into master May 7, 2026
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kriskowal deleted the markm-compartment-mapper-errors branch May 7, 2026 23:52

kriscendobot mentioned this pull request May 13, 2026

chore(ci): create custom CHANGELOG generator #3102

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refactor(compartment-mapper): use @endo/errors#3152

refactor(compartment-mapper): use @endo/errors#3152
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		@@ -1,5 +1,6 @@
		/* Validates a compartment map against its schema. */

		import { Fail, q, b } from '@endo/errors';

		typeof value === 'string' \|\|
		Fail`${b(pathOrMessage)} in ${q(url)} must be a string; got ${q(value)}`;

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Description

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