cli: fix username semantics for userfile

[adityamaru]

Previously, userfile would break if a user had a username with special
characters, which is otherwise supported by CRDB.
This is because, unless specified, userfile uses the username to
generate the underlying storage table names.

This change introduces a new name generation scheme which accounts for
all usernames supported by the database. The details are explained in:
#55389 (comment)

Fixes: #55389

Release note: None

[cockroach-teamcity]

This change is 

[knz]

Very nice! 💯

Reviewed 5 of 5 files at r1.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @adityamaru)

---

pkg/cli/userfile.go, line 182 at r1 (raw file):

// - Support for all current and future valid usernames.
func getDefaultQualifiedTableName(user security.SQLUsername) string {
	if !lexbase.IsRestrictedSQLIdentQuotedOnEncode(user.Normalized()) {

1. to ease readability, what about a username := user.Normalized() at the beginning then reuse that.

2. can you explain why you care whether the username is a reserved keyword? When concatenated with username_, its reserved nature disappears because of the prefix. What do you think?

[adityamaru]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @knz)

---

pkg/cli/userfile.go, line 182 at r1 (raw file):

Previously, knz (kena) wrote…

1. to ease readability, what about a username := user.Normalized() at the beginning then reuse that.

2. can you explain why you care whether the username is a reserved keyword? When concatenated with username_, its reserved nature disappears because of the prefix. What do you think?

good point, i didn't think of that. Switched to just checking whether it is a bare identifier or not.

[knz]

but please revert the now-unnecessary changes

Reviewed 2 of 3 files at r2.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @adityamaru)

---

pkg/sql/lexbase/encode.go, line 54 at r2 (raw file):

// keyword.
func EncodeRestrictedSQLIdent(buf *bytes.Buffer, s string, flags EncodeFlags) {
	if flags.HasFlags(EncBareIdentifiers) || (!isReservedKeyword(s) && IsBareIdentifier(s)) {

you can revert the changes to this file now

---

pkg/sql/lexbase/predicates.go, line 72 at r2 (raw file):

// IsBareIdentifier returns true if the input string is a permissible bare SQL
// identifier.
func IsBareIdentifier(s string) bool {

ditto

[adityamaru]

I had to export IsBareIdentifier() so that I could use it in the userfile logic. The changes to those files are all related to that. Am I misunderstanding something?

[knz]

I had misread. This is fine as is. Go ahead.

Reviewed 1 of 3 files at r2.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @adityamaru)

[adityamaru]

TFTR!

bors r=knz

[craig]

Build succeeded:

• GitHub CI (Cockroach)