Bug when bumping pre-label

[coordt]

My parse, serialize and [tool.bumpversion.parts.pre_label] are pretty much a paste-in from the Automate the pre-release numbering section of the docs:

Configuration

parse = """(?x)
    (?P<major>0|[1-9]\\d*)\\.
    (?P<minor>0|[1-9]\\d*)\\.
    (?P<patch>0|[1-9]\\d*)
    (?:
        -                             # dash separator for pre-release section
        (?P<pre_label>[a-zA-Z-]+)     # pre-release label
        (?P<pre_n>0|[1-9]\\d*)        # pre-release version number
    )?                                # pre-release section is optional
"""

serialize = [
    "{major}.{minor}.{patch}-{pre_label}{distance_to_latest_tag}",
    "{major}.{minor}.{patch}",
]

[tool.bumpversion.parts.pre_label]
values = ["dev", "rc", "final"]
optional_value = "final"

My show-bump shows pre_label bumping up to rc as expected:

Pre-bump State

$ bump-my-version show-bump
0.1.2-dev2 ── bump ─┬─ major ───── 1.0.0-dev2
                    ├─ minor ───── 0.2.0-dev2
                    ├─ patch ───── 0.1.3-dev2
                    ╰─ pre_label ─ 0.1.2-rc2

After Bump

Instead of bump-my-version bump pre_label giving me 0.1.2-rc2, I get rc2 inserted in front of dev2

[tool.bumpversion]
current_version = "0.1.2-rc2-dev2"

The docs don't show any changes to the parse value. Am I missing something?

Originally posted by @dougscc in #271

[coordt]

The bug happens when the labels of the parsing do not match the labels of serialization, and the value is required.

In this example, when the pre_label is dev or rc and the pre_n value is greater than 0, it evaluates the labels_for_format against the version.required_components().

The required labels are {'patch', 'pre_label', 'minor', 'pre_n'}, while the correct serialization labels are {'minor', 'distance_to_latest_tag', 'patch', 'pre_label', 'major'}. The pre_n and the distance_to_latest_tag are equivalent but not currently recognized. When this happens, it defaults to the "{major}.{minor}.{patch}" format.