PEP 753: Add suggested human-readable labels (#3974)

Signed-off-by: William Woodruff <[email protected]>
Co-authored-by: Adam Turner <[email protected]>

peps/pep-0753.rst

@@ -153,85 +153,114 @@ informal relationship between ``Home-page``, ``Download-URL``, and their
 
 This formalization has two parts:
 
-1. A set of rules for canonicalizing ``Project-URL`` labels;
-2. A set of "well-known" canonical label values that indices may specialize
+1. A set of rules for normalizing ``Project-URL`` labels;
+2. A set of "well-known" normalized label values that indices may specialize
    URL presentation for.
 
-Label canonicalization
-----------------------
+Label normalization
+-------------------
 
 The core metadata specification stipulates that ``Project-URL`` labels are
 free text, limited to 32 characters.
 
-This PEP proposes adding the concept of a "canonicalized" label to the core
-metadata specification. Label canonicalization is defined via the following
+This PEP proposes adding the concept of a "normalized" label to the core
+metadata specification. Label normalization is defined via the following
 Python function:
 
 .. code-block:: python
 
     import string
-    def canonicalize_label(label: str) -> str:
+    def normalize_label(label: str) -> str:
         chars_to_remove = string.punctuation + string.whitespace
         removal_map = str.maketrans("", "", chars_to_remove)
         return label.translate(removal_map).lower()
 
-In plain language: a label is *canonicalized* by deleting all ASCII punctuation and
+In plain language: a label is *normalized* by deleting all ASCII punctuation and
 whitespace, and then converting the result to lowercase.
 
 The following table shows examples of labels before (raw) and after
-canonicalization:
+normalization:
 
 .. csv-table::
-    :header: "Raw", "Canonicalized"
+    :header: "Raw", "Normalized"
 
     "``Homepage``", "``homepage``"
     "``Home-page``", "``homepage``"
     "``Home page``", "``homepage``"
     "``Change_Log``", "``changelog``"
     "``What's New?``", "``whatsnew``"
 
-Metadata producers **SHOULD** emit the canonicalized form of a user
-specified label, but **MAY** choose to emit the un-canonicalized form so
+Metadata producers **SHOULD** emit the normalized form of a user
+specified label, but **MAY** choose to emit the un-normalized form so
 long as it adheres to the existing 32 character constraint.
 
-Package indices **SHOULD NOT** use the canonicalized labels belonging to the set
+Package indices **SHOULD NOT** use the normalized labels belonging to the set
 of well-known labels directly as UI elements (instead replacing them with
 appropriately capitalized text labels). Labels not belonging to the well-known
 set **MAY** be used directly as UI elements.
 
 Well-known labels
 -----------------
 
-In addition to the canonicalization rules above, this PEP proposes a
+In addition to the normalization rules above, this PEP proposes a
 fixed (but extensible) set of "well-known" ``Project-URL`` labels,
-as well as equivalent aliases.
-
-The following table lists these labels, in canonical form:
-
-.. csv-table::
-    :header: "Label", "Description", "Aliases"
-    :widths: 20, 50, 30
-
-    "``homepage``", "The project's home page", "*(none)*"
-    "``download``", "A download URL for the current distribution, equivalent to ``Download-URL``", "*(none)*"
-    "``changelog``", "The project's changelog", "``changes``, ``releasenotes``, ``whatsnew``, ``history``"
-    "``documentation``", "The project's online documentation", "``docs``"
-    "``issues``", "The project's bug tracker", "``bugs``, ``issue``, ``bug``, ``tracker``, ``report``"
-    "``sponsor``", "Sponsoring information", "``funding``, ``donate``, ``donation``"
+as well as aliases and human-readable equivalents.
+
+The following table lists these labels, in normalized form:
+
+.. list-table::
+   :header-rows: 1
+
+   * - Label (Human-readable equivalent)
+     - Description
+     - Aliases
+   * - ``homepage`` (Homepage)
+     - The project's home page
+     - *(none)*
+   * - ``source`` (Source Code)
+     - The project's hosted source code or repository
+     - ``repository``, ``sourcecode``, ``github``
+   * - ``download`` (Download)
+     - A download URL for the current distribution, equivalent to ``Download-URL``
+     - *(none)*
+   * - ``changelog`` (Changelog)
+     - The project's comprehensive changelog
+     - ``changes``, ``whatsnew``, ``history``
+   * - ``releasenotes`` (Release Notes)
+     - The project's curated release notes
+     - *(none)*
+   * - ``documentation`` (Documentation)
+     - The project's online documentation
+     - ``docs``
+   * - ``issues`` (Issue Tracker)
+     - The project's bug tracker
+     - ``bugs``, ``issue``, ``tracker``, ``issuetracker``, ``bugtracker``
+   * - ``funding`` (Funding)
+     - Funding Information
+     - ``sponsor``, ``donate``, ``donation``
+
+Indices **MAY** choose to use the human-readable equivalents suggested above
+in their UI elements, if appropriate. Alternatively, indices **MAY** choose
+their own appropriate human-readable equivalents for UI elements.
 
 Packagers and metadata producers **MAY** choose to use these well-known
-labels to communicate specific URL intents to package indices and downstreams.
+labels or their aliases to communicate specific URL intents to package indices
+and downstreams.
 
-Packagers and metadata producers **SHOULD** produce the canonicalized version
-of the well-known labels in package metadata.
+Packagers and metadata producers **SHOULD** produce the normalized version
+of the well-known labels or their aliases in package metadata. Packaging tools
+**MUST NOT** transform between equivalent aliases, i.e.. **SHOULD**
+normalize ``GitHub`` to ``github`` but **MUST NOT** transform
+``github`` to ``source``.
 
 Similarly, indices **MAY** choose to specialize their rendering or presentation
 of URLs with these labels, e.g. by presenting an appropriate icon or tooltip
 for each label.
 
-Indices **MAY** also specialize the rendering or presentation of additional labels or URLs,
-including (but not limited to), labels that start with a well-known label, and URLs that refer
-to a known service provider domain (e.g. for documentation hosting or issue tracking).
+Indices **MAY** also specialize the rendering or presentation of additional
+labels or URLs, including (but not limited to), labels that start with a
+well-known label, and URLs that refer to a known service provider domain (e.g.
+for documentation hosting or issue tracking).
 
 This PEP recognizes that the list of well-known labels is unlikely to remain
 static, and that subsequent additions to it should not require the overhead
@@ -275,11 +304,11 @@ the core metadata standards:
   next major core metadata version. If removed, package indices and consumers
   **MUST** reject metadata containing these fields when said metadata is of
   the new major version.
-* Enforcement of label canonicalization. If enforced, package producers
-  **MUST** emit only canonicalized ``Project-URL`` labels when generating
+* Enforcement of label normalization. If enforced, package producers
+  **MUST** emit only normalized ``Project-URL`` labels when generating
   distribution metadata, and package indices and consumers **MUST** reject
-  distributions containing non-canonicalized labels. Note: requiring
-  canonicalization merely restricts labels to lowercase text, and excludes
+  distributions containing non-normalized labels. Note: requiring
+  normalization merely restricts labels to lowercase text, and excludes
   whitespace and punctuation. It does NOT restrict project URLs solely to
   the use of "well-known" labels.
 
@@ -292,7 +321,7 @@ Security Implications
 
 This PEP does not identify any positive or negative security implications
 associated with deprecating ``Home-page`` and ``Download-URL`` or with
-label canonicalization.
+label normalization.
 
 How To Teach This
 =================