[Inf1mum]

Fixes #25527.

The dart-dio generator built request paths by substituting path parameters through the api/query_param helper — which (for built_value) passes strings through unchanged and (for freezed / json_serializable) interpolates the raw value. A path parameter containing /, spaces, or other reserved characters was therefore sent unencoded and broke the request path (e.g. a scanned QR-code URL as {bin} → 404).

What changed

• New serialization/<library>/api/path_param.mustache for all three serialization libraries (built_value, freezed, json_serializable) wrapping the existing query_param rendering in Uri.encodeComponent(...) — suggested in the issue and credited to the reporter.
• api.mustache now substitutes path parameters via api/path_param instead of api/query_param.

Uri.encodeComponent encodes the value as a single path component (including / → %2F), so values containing slashes stay within one segment — exactly the failing scenario from the issue.

Verification

• New unit test testPathParamsAreUriEncoded generates the petstore client for all three serialization libraries and asserts Uri.encodeComponent( appears in the generated API classes. DartDioClientCodegenTest: 20 tests, 0 failures.
• Regenerated all 9 dart-dio sample configs; every path substitution now goes through Uri.encodeComponent.
• dart analyze on the regenerated built_value petstore sample: no issues (one pre-existing unrelated unused_import warning).

PR checklist

• Read the contribution guidelines.
• Regenerated the affected samples via ./bin/generate-samples.sh (all dart-dio configs); no files deleted.
• Pull request is created against the master branch.

---

Summary by cubic

Fixes #25527. Generated dart-dio clients now URI-encode path parameters, so values containing / or spaces no longer break the request path.

• Path parameters are substituted via a new api/path_param partial for all three serialization libraries (built_value, freezed, json_serializable), wrapping the value in Uri.encodeComponent on a single line to keep the generated path style unchanged.
• api.mustache now uses this partial for path parameters instead of the query-param rendering.
• Adds a unit test covering all three serialization libraries that asserts every path substitution in each generated API class is URI-encoded, and regenerates the affected samples.
• Pins source_helper to >=1.3.8 <1.4.0 in the freezed variant's pubspec.mustache; version 1.4.0 added extension members that clash with json_serializable 6.x and break the build_runner build script, while 1.3.9+ requires Dart 3.9 (above the variant's advertised >=3.8.0).

^{Written for commit 594a4aa. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 17 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="modules/openapi-generator/src/test/java/org/openapitools/codegen/dart/dio/DartDioClientCodegenTest.java">

<violation number="1" location="modules/openapi-generator/src/test/java/org/openapitools/codegen/dart/dio/DartDioClientCodegenTest.java:499">
P2: These independent substring assertions do not prove that path parameters are encoded. Assert the complete placeholder replacement expression, or exercise a generated client with a value containing `/` or spaces and verify the resulting request path.</violation>
</file>

<sub>Reply with feedback, questions, or to request a fix.

View guided diff | Re-trigger cubic</sub>

[cubic-dev-ai]

P2: These independent substring assertions do not prove that path parameters are encoded. Assert the complete placeholder replacement expression, or exercise a generated client with a value containing / or spaces and verify the resulting request path.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. When an issue isn't valid or won't be fixed in this PR, reply in its thread with the reason and then resolve the thread. At modules/openapi-generator/src/test/java/org/openapitools/codegen/dart/dio/DartDioClientCodegenTest.java, line 499:

<comment>These independent substring assertions do not prove that path parameters are encoded. Assert the complete placeholder replacement expression, or exercise a generated client with a value containing `/` or spaces and verify the resulting request path.</comment>

<file context>
@@ -471,6 +471,37 @@ public void testFreezedIgnoresUseOptional() throws IOException {
+
+            Path petApi = output.toPath().resolve("lib/src/api/pet_api.dart");
+            String content = Files.readString(petApi, StandardCharsets.UTF_8);
+            Assert.assertTrue(content.contains(".replaceAll("), content);
+            Assert.assertTrue(content.contains("Uri.encodeComponent("),
+                    "path parameter should be URI-encoded in " + serializationLibrary + ": " + content);
</file context>

[Inf1mum]

Strengthened in 5301a77: testPathParamsAreUriEncoded now iterates every generated *_api.dart file and asserts the count of Uri.encodeComponent( calls equals the count of .replaceAll( path substitutions — so any future path substitution added without encoding fails the test. 20 tests, 0 failures.

[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

<sub>Reply with feedback, questions, or to request a fix.

View guided diff | Re-trigger cubic</sub>

[wing328]

thanks for the PR

cc @jaumard (2018/09) @amondnet (2019/12) @sbu-WBT (2020/12) @kuhnroyal (2020/12) @agilob (2020/12) @ahmednfwela (2021/08)

[wing328]

lgtm. let's give it a try