Review: fix: treat --shared-server as server mode for DoltMode

Verdict: LGTM with one gap to flag

The Problem

bd init --shared-server set the BEADS_DOLT_SHARED_SERVER env var (for directory resolution) but never set initServerMode = true. Since initServerMode controls what gets written to metadata.json, the file ended up with dolt_mode: "embedded". Every subsequent command read that and operated in embedded mode — including bd dolt start which errored with "not supported in embedded mode."

The Fix

2 files, +13 −0. Two complementary patches:

1. Init fix (init.go, +6 lines):

if sharedServer {
    initServerMode = true
}

Inserted after the BEADS_DOLT_SERVER_MODE=1 env var check, before serverMode = initServerMode propagates to the global. Now bd init --shared-server writes dolt_mode: "server" to metadata.json. Straightforward.

2. Runtime fix (main.go, +6 lines):

if !doltCfg.ServerMode && doltserver.IsSharedServerMode() {
    doltCfg.ServerMode = true
}

Inserted between cfg.IsDoltServerMode() and serverMode = doltCfg.ServerMode in PersistentPreRunE. Handles existing installs that already have stale dolt_mode: "embedded" in metadata.json without requiring a re-init. IsSharedServerMode() checks BEADS_DOLT_SHARED_SERVER env var first, then dolt.shared-server in config.yaml.

Correctness ✅

• Init path: sharedServer is parsed at line 79, the new block fires before serverMode = initServerMode at line 137, and before the env var propagation at line 145. The ordering is correct — initServerMode is fully resolved before any consumer reads it.

• Runtime path: The override fires only when cfg.IsDoltServerMode() returned false (stale metadata.json) AND IsSharedServerMode() returns true (config.yaml or env var says shared). Both serverMode and cmdCtx.ServerMode get the corrected value because the override inserts before those assignments.

• No double-setting. New installs (post-fix) will have dolt_mode: "server" in metadata.json, so cfg.IsDoltServerMode() returns true directly. The !doltCfg.ServerMode guard prevents the redundant IsSharedServerMode() call.

• IsSharedServerMode() is well-tested. It checks env var ("1" or "true", case-insensitive) then config.GetBool("dolt.shared-server"). Both sources are idempotent reads.

Edge Cases 🔍

1. --shared-server combined with --server. Both set initServerMode = true. No conflict — idempotent.

2. Existing install: config.yaml has dolt.shared-server: true, metadata.json has dolt_mode: "embedded". The runtime fix catches this: cfg.IsDoltServerMode() returns false, IsSharedServerMode() returns true, override activates. Correct.

3. Existing install: neither config.yaml nor env var indicates shared server, metadata.json says embedded. IsSharedServerMode() returns false, no override. Correctly remains embedded.

⚠️ Gap: loadServerModeFromConfig() at line 158

There is a second code path that resolves server mode — loadServerModeFromConfig() at line 158, called at line 429, before the no-db command early return. It reads cfg.IsDoltServerMode() and sets serverMode + cmdCtx.ServerMode, but does not have the shared-server override.

This means no-db commands (bd doctor, bd bootstrap, bd dolt status, bd context, bd dolt start) that exit through the early return at the no-db check will still see serverMode = false for stale metadata.json installs with dolt.shared-server: true.

In particular: bd dolt start is listed in the no-db command set. If it checks isEmbeddedMode() (which reads the global serverMode), it will still error for stale installs. The PersistentPreRun override only applies to commands that continue past the no-db guard.

Consider applying the same override to loadServerModeFromConfig():

func loadServerModeFromConfig() {
    beadsDir := beads.FindBeadsDir()
    if beadsDir == "" {
        return
    }
    cfg, err := configfile.Load(beadsDir)
    if err != nil || cfg == nil {
        return
    }
    sm := cfg.IsDoltServerMode()
    if !sm && doltserver.IsSharedServerMode() {
        sm = true
    }
    serverMode = sm
    if cmdCtx != nil {
        cmdCtx.ServerMode = sm
    }
}

This would close the gap for all command paths.

Performance ✅

IsSharedServerMode() is an env var read + a config key lookup. Negligible. Guarded by !doltCfg.ServerMode so it only runs when needed.

Style ✅

• Comments reference the issue number (GH#2946). Clear.
• Minimal diff — no unrelated changes.
• No tests added, though the test plan in the PR body is manual. For a 2-line logic fix with clear before/after behavior, manual verification is reasonable.

Ship the init fix and the PersistentPreRun override. Consider extending loadServerModeFromConfig() with the same shared-server override to close the no-db command gap.