export wiki: a community relabelled only by case loses its article on case-insensitive filesystems (orphan sweep compares names case-sensitively) #4508

What happened?

On a case-insensitive filesystem (the macOS APFS default; also NTFS), to_wiki deletes a community's article when the community's label changes only in letter case between two exports, for example groups → Groups. index.md still links to Groups.md, which no longer exists.

The cause is the end-of-run orphan sweep in graphify/wiki.py (to_wiki, around line 451):

for old_article in out.glob("*.md"):
    if old_article.name not in produced:
        old_article.unlink()

produced contains Groups.md. On a case-preserving, case-insensitive filesystem, the existing directory entry keeps its old name, groups.md: the atomic write replaces the file's contents but not the name's case. "groups.md" not in {"Groups.md"} is true, so the sweep unlinks groups.md, which is the very file this run just wrote.

Expected: the article survives, ideally under the new case, and the link in index.md resolves.

_unique_slug already folds case when it checks for collisions, so the sweep looks like the one remaining case-sensitive comparison. Possible fixes:

• compare folded names, e.g. old_article.name.casefold() not in {p.casefold() for p in produced};
• or skip any path that os.path.samefiles a produced one.

To get the new case onto disk as well, rename case-only changes before writing.

The end-of-run sweep arrived with the #3060 fix. The earlier up-front unlink, as I understand it, didn't have this problem.

Steps to reproduce

import pathlib, tempfile
import networkx as nx
from graphify.wiki import to_wiki

G = nx.Graph()
G.add_node("a", label="parse()", source_file="src/a.py", file_type="code")
G.add_node("b", label="tokenize()", source_file="src/b.py", file_type="code")
G.add_edge("a", "b", relation="calls")
out = pathlib.Path(tempfile.mkdtemp()) / "wiki"

to_wiki(G, {0: ["a", "b"]}, out, community_labels={0: "groups"})
print(sorted(p.name for p in out.glob("*.md")))
to_wiki(G, {0: ["a", "b"]}, out, community_labels={0: "Groups"})   # case-only relabel
print(sorted(p.name for p in out.glob("*.md")))
print([l for l in (out / "index.md").read_text().splitlines() if "roups" in l])
print((out / "Groups.md").exists())
to_wiki(G, {0: ["a", "b"]}, out, community_labels={0: "Groups"})   # same labels again
print(sorted(p.name for p in out.glob("*.md")))

In practice it happens when graphify label or a manual relabel changes only the case of a community name, or when re-clustering gives a community a hub-derived name that differs only in case.

Output

['groups.md', 'index.md']
['index.md']
['- [Groups](Groups.md) — 2 nodes']
False
['Groups.md', 'index.md']

Only the export that changes the case loses the article. The next export with the same labels writes it again, so the wiki stays broken until another export runs.

Environment

• Graphify version: 0.9.91 (graphifyy[sql,terraform])
• OS: macOS 27.0.1, APFS (case-insensitive, case-preserving)
• Python: 3.14.8, networkx 3.7
• Installation method: uv tool install
• No provider keys are involved; this is a pure export with no LLM calls. The snippet reproduces it in a fresh temp directory.

Related: #2650, the same class of case-only collision in to_obsidian.