feat(git-gate): remove git remote host override plumbing

bot_bottle/git_gate.py

@@ -30,11 +30,9 @@ backend-specific and lives on concrete subclasses (see
 from __future__ import annotations
 
 from abc import ABC, abstractmethod
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from pathlib import Path
-from typing import Mapping
 
-from .log import die
 from .manifest import Bottle, GitEntry
 
 
@@ -47,10 +45,6 @@ GIT_GATE_HOSTNAME = "git-gate"
 GIT_GATE_DAEMON_TIMEOUT_SECS = 15
 
 
-def _empty_str_map() -> dict[str, str]:
-    return {}
-
-
 @dataclass(frozen=True)
 class GitGateUpstream:
     """One bare repo on the gate. `name` drives the bare-repo path
@@ -64,10 +58,7 @@ class GitGateUpstream:
     KnownHostKey string from the manifest; the gate's start step
     materialises it into a known_hosts file if non-empty.
 
-    `extra_hosts` is a `{hostname: ip}` map the backend injects into
-    the gate container's `/etc/hosts` via `--add-host` so the gate
-    can resolve upstream hostnames that aren't reachable via the
-    container's default DNS (e.g. Tailscale-only hosts)."""
+    the gate credential paths inside the running sidecar."""
 
     name: str
     upstream_url: str
@@ -76,7 +67,6 @@ class GitGateUpstream:
     identity_file: str
     known_host_key: str
     known_hosts_file: Path = Path()
-    extra_hosts: Mapping[str, str] = field(default_factory=_empty_str_map)
 
 
 @dataclass(frozen=True)
@@ -113,38 +103,11 @@ def git_gate_upstreams_for_bottle(bottle: Bottle) -> tuple[GitGateUpstream, ...]
             upstream_port=e.UpstreamPort,
             identity_file=e.IdentityFile,
             known_host_key=e.KnownHostKey,
-            extra_hosts=dict(e.ExtraHosts),
         )
         for e in bottle.git
     )
 
 
-def git_gate_aggregate_extra_hosts(
-    upstreams: tuple[GitGateUpstream, ...],
-) -> dict[str, str]:
-    """Merge every upstream's `extra_hosts` into a single
-    `{hostname: ip}` map for `--add-host` on the gate container. Two
-    entries naming the same hostname with different IPs is a manifest
-    bug — the gate has one /etc/hosts — so die loudly with the
-    conflicting names rather than silently picking one."""
-    merged: dict[str, str] = {}
-    source: dict[str, str] = {}
-    for u in upstreams:
-        for host, ip in u.extra_hosts.items():
-            existing = merged.get(host)
-            if existing is None:
-                merged[host] = ip
-                source[host] = u.name
-            elif existing != ip:
-                die(
-                    f"git-gate ExtraHosts conflict: '{host}' maps to "
-                    f"'{existing}' in upstream '{source[host]}' and to "
-                    f"'{ip}' in upstream '{u.name}'. The gate has one "
-                    f"/etc/hosts; pick one IP."
-                )
-    return merged
-
-
 def git_gate_render_gitconfig(
     entries: tuple[GitEntry, ...], gate_host: str, *, scheme: str = "git",
 ) -> str:
@@ -443,7 +406,6 @@ class GitGate(ABC):
                     identity_file=u.identity_file,
                     known_host_key=u.known_host_key,
                     known_hosts_file=known_hosts_file,
-                    extra_hosts=dict(u.extra_hosts),
                 )
             )
         return GitGatePlan(