Add pyproject.toml manifest support (PEP 621) by ChrisJr404 · Pull Request #1842 · o2sh/onefetch

ChrisJr404 · 2026-08-18T09:43:08Z

Closes #1590. This adds pyproject.toml to the set of manifests onefetch understands, so Python projects show a dependency count, description, version and license just like Cargo and npm projects already do.

Following the discussion on the issue, I focused on the format specified by the PEPs rather than tool-specific layouts. A new ManifestType::PyProject reads the PEP 621 [project] table:

number_of_dependencies from project.dependencies
name / version / description from their project.* fields
license from project.license, handled as either a PEP 639 SPDX string or the older { text = "..." } table. A { file = "LICENSE" } table carries no identifier, so it's left unset and onefetch falls back to detecting the license from the repo as before.

Tool-specific tables such as [tool.poetry] use a different shape and are intentionally out of scope here.

Parsing uses toml, which was already in the tree via cargo_toml, so Cargo.lock only gains the existing version as a direct dependency of the manifest crate. In the Dependencies field this reads as e.g. 3 (pyproject.toml).

Tests

manifest/tests/pyproject.rs with a tests/fixtures/pyproject/ fixture, mirroring the existing cargo/npm integration tests.
A unit test in manifest/src/lib.rs covering the three PEP 621 license forms (SPDX string, { text } table, { file } table).
Verified end to end against a scratch git repo containing a pyproject.toml: onefetch prints Dependencies: 3 (pyproject.toml) and picks up the description, version and license. cargo fmt --all --check, cargo clippy, and the full test suite pass.

Parse a repository's pyproject.toml [project] table so onefetch reports the project's dependency count, name, version, description and license for Python projects, the same way it already does for Cargo.toml and package.json.

spenserblack

Thanks! Mostly looks good, I just have a few nitpicks.

spenserblack · 2026-08-18T11:46:02Z

 pub enum ManifestType {
    Npm,
    Cargo,
+    #[strum(to_string = "pyproject.toml")]


Do we want to set the to_string to "pyproject.toml"? We don't call the Npm variant "package.json", or the Cargo variant "Cargo.toml".

spenserblack · 2026-08-18T11:55:12Z

+    // A `license = { file = "LICENSE" }` table carries no identifier, so leave it
+    // unset and let onefetch fall back to detecting the license from the repo.
+    let license = project.license.and_then(|license| match license {
+        PyProjectLicense::Spdx(spdx) => Some(spdx),
+        PyProjectLicense::Table { text } => text,
+    });


I was a bit confused by this for a moment, but, if I understand it correctly, the value of license.text (if license is a table) may also be the SPDX identifier? But it seems like license.text may be any string if the project uses a non-standard license? Could you clarify this in the comment?

spenserblack · 2026-08-18T12:06:26Z

+        // SPDX expression string (PEP 639)
+        let spdx: PyProjectTable = toml::from_str("license = \"MIT\"").unwrap();
+        assert!(matches!(spdx.license, Some(PyProjectLicense::Spdx(s)) if s == "MIT"));
+
+        // `{ text = "..." }` table (older PEP 621 form)
+        let text: PyProjectTable = toml::from_str("license = { text = \"Apache-2.0\" }").unwrap();
+        assert!(
+            matches!(text.license, Some(PyProjectLicense::Table { text: Some(t) }) if t == "Apache-2.0")
+        );
+
+        // `{ file = "LICENSE" }` table carries no identifier
+        let file: PyProjectTable = toml::from_str("license = { file = \"LICENSE\" }").unwrap();
+        assert!(matches!(
+            file.license,
+            Some(PyProjectLicense::Table { text: None })
+        ));
+    }


Instead of using 3 assert!, I think you can use rstest to make this 3 test cases instead. That way a prior failure wouldn't block the following test cases from running.

… comment, use rstest - Remove the strum to_string override so PyProject renders like the other variants (Npm/Cargo) instead of pyproject.toml. - Expand the PyProjectLicense doc/comment to explain that license.text is free-form and only conventionally an SPDX identifier. - Convert the three license-form assertions into rstest cases so one failure no longer masks the others.

ChrisJr404 · 2026-08-18T13:24:57Z

Thanks for the review! Pushed a commit addressing all three:

to_string = "pyproject.toml" — good catch, that was inconsistent with Npm/Cargo. Dropped the override so PyProject renders via the default variant name, matching the others.
license.text comment — you've got it exactly right: text is free-form. It's conventionally an SPDX identifier (e.g. MIT), but PEP 621 permits any string, including the full text of a non-standard license. We surface whatever's there verbatim rather than trying to validate it as SPDX. I expanded the doc comment on PyProjectLicense and the inline comment in parse_pyproject_manifest to spell this out, and to note that a { file = ... } table carries no identifier (so we fall back to repo license detection).
assert! → rstest — converted to three #[case]s so a failure in one form no longer blocks the others. Added rstest as a dev-dependency on the onefetch-manifest crate (the workspace already pins 0.26.1).

spenserblack

Thanks! Just these last two changes and LGTM!

spenserblack · 2026-08-18T14:32:01Z

I hate to do this, but one more thing, since it looks like you've managed to author over 90 pull requests today alone: have you read our contributing guidelines (including our AI policy)?

spenserblack

Oops, I thought just using rstest.workspace = true was enough to synchronize the versions, but looks like a little bit more work is needed.

TBH you can just revert bd4491b. I'll look into utilizing that feature some other time.

Add pyproject.toml manifest support (PEP 621)

381920e

Parse a repository's pyproject.toml [project] table so onefetch reports the project's dependency count, name, version, description and license for Python projects, the same way it already does for Cargo.toml and package.json.

vercel Bot deployed to Preview August 18, 2026 09:43 View deployment

spenserblack reviewed Aug 18, 2026

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vercel Bot deployed to Preview August 18, 2026 13:25 View deployment

spenserblack requested changes Aug 18, 2026

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Comment thread manifest/Cargo.toml Outdated

Comment thread manifest/src/lib.rs Outdated

spenserblack added 2 commits August 18, 2026 15:18

Synchronize rstest with workspace

bd4491b

Name test cases

3dcce71

vercel Bot deployed to Preview August 18, 2026 19:19 View deployment

spenserblack requested changes Aug 18, 2026

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Add pyproject.toml manifest support (PEP 621) - #1842

Add pyproject.toml manifest support (PEP 621)#1842
ChrisJr404 wants to merge 4 commits into
o2sh:mainfrom
ChrisJr404:pyproject-manifest

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