merge mimeapps defaults via modify_ script instead of full replace

mimeapps.list is rewritten by the desktop environment, so managing it as a whole file made chezmoi update clobber each machine's own associations. Replace the full-file template with a modify_ script that merges only the enforced entries (per-host browser for text/html + http/https, and the nvim text-type defaults) into whatever the machine already has, preserving everything else.
2026-08-28 16:12:30 -04:00
parent 2b2c702010
commit 951cdb1d36
2 changed files with 69 additions and 27 deletions
@@ -0,0 +1,69 @@
+#!/usr/bin/env python3
+{{ $browser := "firefox.desktop" }}{{ if hasPrefix "UGC" .chezmoi.hostname }}{{ $browser = "default-browser.desktop" }}{{ end }}
+# chezmoi modify_ script: merge a curated set of default associations into the
+# machine's existing mimeapps.list (read from stdin) instead of replacing the
+# whole file, so each machine keeps its own entries.
+import sys
+
+BROWSER = "{{ $browser }}"
+SECTION = "[Default Applications]"
+
+# Associations enforced on every machine, in [Default Applications].
+ENFORCED = {
+    "application/json": "nvim.desktop",
+    "application/x-docbook+xml": "nvim.desktop",
+    "application/x-yaml": "nvim.desktop",
+    "text/markdown": "nvim.desktop",
+    "text/x-cmake": "nvim.desktop",
+    "text/html": BROWSER,
+    "x-scheme-handler/http": BROWSER,
+    "x-scheme-handler/https": BROWSER,
+}
+
+
+def main():
+    lines = sys.stdin.read().splitlines()
+
+    # Split into sections, preserving header lines and body order. The first
+    # (headerless) section holds any preamble before the first [Header].
+    sections = [[None, []]]
+    for line in lines:
+        stripped = line.strip()
+        if stripped.startswith("[") and stripped.endswith("]"):
+            sections.append([stripped, []])
+        else:
+            sections[-1][1].append(line)
+
+    target = next((s for s in sections if s[0] == SECTION), None)
+    if target is None:
+        target = [SECTION, []]
+        sections.append(target)
+
+    remaining = dict(ENFORCED)
+    body = []
+    for line in target[1]:
+        key = line.split("=", 1)[0].strip() if "=" in line else None
+        if key in remaining:
+            body.append("{}={};".format(key, remaining.pop(key)))
+        else:
+            body.append(line)
+
+    # Append any still-missing enforced keys before trailing blank lines.
+    trailing = []
+    while body and body[-1].strip() == "":
+        trailing.insert(0, body.pop())
+    for key, val in ENFORCED.items():
+        if key in remaining:
+            body.append("{}={};".format(key, val))
+    body.extend(trailing)
+    target[1] = body
+
+    out = []
+    for header, section_body in sections:
+        if header is not None:
+            out.append(header)
+        out.extend(section_body)
+    sys.stdout.write("\n".join(out) + "\n")
+
+
+main()