Fold long header fields in Python metadata

Cargo.toml

@@ -58,6 +58,7 @@ scroll = "0.10.2"
 target-lexicon = "0.12.0"
 pyproject-toml = "0.1.0"
 python-pkginfo = "0.4.0"
+textwrap = "0.14.2"
 
 [dev-dependencies]
 indoc = "1.0.3"

Changelog.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Use UTF-8 encoding when reading `pyproject.toml` by domdfcoding in [#588](https://github.com/PyO3/maturin/pull/588)
 * Use Cargo's `repository` field as `Source Code` in project URL in [#590](https://github.com/PyO3/maturin/pull/590)
+* Fold long header fields in Python metadata in [#594](https://github.com/PyO3/maturin/pull/594)
 
 ## [0.11.1] - 2021-07-10
 

Readme.md

@@ -124,6 +124,7 @@ my-project
 ## Python metadata
 
 maturin supports [PEP 621](https://www.python.org/dev/peps/pep-0621/), you can specify python package metadata in `pyproject.toml`.
+maturin merges metadata from `Cargo.toml` and `pyproject.toml`, `pyproject.toml` take precedence over `Cargo.toml`.
 
 To specify python dependencies, add a list `dependencies` in a `[project]` section in the `pyproject.toml`. This list is equivalent to `install_requires` in setuptools:
 

src/metadata.rs

@@ -171,8 +171,12 @@ impl Metadata21 {
                         (None, None) => {}
                     }
                 }
-                self.author = Some(names.join(", "));
-                self.author_email = Some(emails.join(", "));
+                if !names.is_empty() {
+                    self.author = Some(names.join(", "));
+                }
+                if !emails.is_empty() {
+                    self.author_email = Some(emails.join(", "));
+                }
             }
 
             if let Some(maintainers) = &project.maintainers {
@@ -192,8 +196,12 @@ impl Metadata21 {
                         (None, None) => {}
                     }
                 }
-                self.maintainer = Some(names.join(", "));
-                self.maintainer_email = Some(emails.join(", "));
+                if !names.is_empty() {
+                    self.maintainer = Some(names.join(", "));
+                }
+                if !emails.is_empty() {
+                    self.maintainer_email = Some(emails.join(", "));
+                }
             }
 
             if let Some(keywords) = &project.keywords {
@@ -383,15 +391,15 @@ impl Metadata21 {
             }
         };
 
-        add_option("Summary", &self.summary);
+        add_option("Summary", &self.summary.as_deref().map(fold_header));
         add_option("Keywords", &self.keywords);
         add_option("Home-Page", &self.home_page);
         add_option("Download-URL", &self.download_url);
         add_option("Author", &self.author);
         add_option("Author-email", &self.author_email);
         add_option("Maintainer", &self.maintainer);
         add_option("Maintainer-email", &self.maintainer_email);
-        add_option("License", &self.license);
+        add_option("License", &self.license.as_deref().map(fold_header));
         add_option("Requires-Python", &self.requires_python);
         add_option("Description-Content-Type", &self.description_content_type);
         // Project-URL is special
@@ -463,6 +471,28 @@ impl Metadata21 {
     }
 }
 
+/// Fold long header field according to RFC 5322 section 2.2.3
+/// https://datatracker.ietf.org/doc/html/rfc5322#section-2.2.3
+fn fold_header(text: &str) -> String {
+    let mut result = String::with_capacity(text.len());
+
+    let options = textwrap::Options::new(78)
+        .initial_indent("")
+        .subsequent_indent("\t");
+    for (i, line) in textwrap::wrap(text, options).iter().enumerate() {
+        if i > 0 {
+            result.push_str("\r\n");
+        }
+        if line.is_empty() {
+            result.push('\t');
+        } else {
+            result.push_str(&line);
+        }
+    }
+
+    result
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
@@ -740,6 +770,6 @@ mod test {
                 "attrs; extra == 'test'",
                 "boltons; (sys_platform == 'win32') and extra == 'test'"
             ]
-        )
+        );
     }
 }

test-crates/pyo3-pure/LICENSE

@@ -0,0 +1,25 @@
+Copyright (c) 2018-present konstin
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

test-crates/pyo3-pure/pyproject.toml

@@ -12,6 +12,7 @@ readme = "Readme.md"
 maintainers = [
     {name = "messense", email = "[email protected]"}
 ]
+license = { file = "LICENSE" }
 
 [project.optional-dependencies]
 test = [