Duplicate header with --prepend

[azzamsa]

Hi,

When using --prepend, I encounter two headers: the existing header in the CHANGELOG file and the new prepended header. Is this the expected behavior?

Should we manually remove the previous header in the CHANGELOG file?
Alternatively, is there an option such as --strip-previous-header?

If manual removal of the previous header is required, I suggest improving the wording as follows:

-# 1- changelog header is removed from CHANGELOG.md
+# 1- remove the changelog header from CHANGELOG.md manually
# 2- new entries are prepended to CHANGELOG.md without the footer part
git cliff --unreleased --tag 1.0.0 --prepend CHANGELOG.md

Thank you for git-cliff! 🎖️

[orhun]

Hello! 🐻

Actually this is unexpected behavior - --prepend should automatically strip the previous header.

Can you share your config so that I can look into what went wrong?

[orhun]

Can you share your git-cliff config and some example commits from your repo?

[tmlmt]

Here's the cliff.toml config file:

# git-cliff ~ configuration file
# https://git-cliff.org/docs/configuration

[changelog]
# changelog header
header = """
# Changelog\n
All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines.\n
"""
# template for the changelog body
# https://keats.github.io/tera/docs/#introduction
body = """
---
{% if version %}\
    {% if previous.version %}\
        ## [{{ version | trim_start_matches(pat="v") }}]($REPO/compare/{{ previous.version }}..{{ version }}) - {{ timestamp | date(format="%Y-%m-%d") }}
    {% else %}\
        ## [{{ version | trim_start_matches(pat="v") }}] - {{ timestamp | date(format="%Y-%m-%d") }}
    {% endif %}\
{% else %}\
    ## [unreleased]
{% endif %}\
{% for group, commits in commits | group_by(attribute="group") %}
    ### {{ group | striptags | trim | upper_first }}
    {% for commit in commits
    | filter(attribute="scope")
    | sort(attribute="scope") %}
        - **({{commit.scope}})**{% if commit.breaking %} [**breaking**]{% endif %} \
            {{ commit.message }} - ([{{ commit.id | truncate(length=7, end="") }}]($REPO/commit/{{ commit.id }})) - {{ commit.author.name }}
    {%- endfor -%}
    {% raw %}\n{% endraw %}\
    {%- for commit in commits %}
        {%- if commit.scope -%}
        {% else -%}
            - {% if commit.breaking %} [**breaking**]{% endif %}\
                {{ commit.message }} - ([{{ commit.id | truncate(length=7, end="") }}]($REPO/commit/{{ commit.id }})) - {{ commit.author.name }}
        {% endif -%}
    {% endfor -%}
{% endfor %}\n
"""
# template for the changelog footer
footer = """
<!-- generated by git-cliff -->
"""
# remove the leading and trailing whitespace from the templates
trim = true
# postprocessors
postprocessors = [
    { pattern = '\$REPO', replace = "https://<repo>" }, # replace repository URL
]

[git]
# parse the commits based on https://www.conventionalcommits.org
conventional_commits = true
# filter out the commits that are not conventional
filter_unconventional = true
# process each line of a commit as an individual commit
split_commits = false
# regex for preprocessing the commit messages
commit_preprocessors = [
    # { pattern = '\((\w+\s)?#([0-9]+)\)', replace = "([#${2}](https://github.com/orhun/git-cliff/issues/${2}))"}, # replace issue numbers
]
# regex for parsing and grouping commits
commit_parsers = [
    { message = "^feat", group = "<!-- 00 -->🚀 Enhancements" },
    { message = "^fix", group = "<!-- 01 -->🩹 Fixes" },
    { message = "^perf", group = "<!-- 02 -->🔥 Performance" },
    { message = "^revert", group = "<!-- 03 -->◀️ Revert" },
    { message = "^refactor", group = "<!-- 04 -->🚜 Refactor" },
    { message = "^style", group = "<!-- 05 -->🎨 Style" },
    { message = "^types", group = "<!-- 06 -->🌊 Types" },
    { message = "^test", group = "<!-- 07 -->🧪 Tests" },
    { message = "^doc", group = "<!-- 08 -->📚 Documentation" },
    { message = "^build", group = "<!-- 09 -->📦 Build" },
    { message = "^ci", group = "<!-- 10 -->🤖 CI" },
    { message = "^chore\\(version\\):", skip = true },
    { message = "^chore\\(ignore\\):", skip = true },
    { message = "^chore", group = "<!-- 11 -->🏡 Chore" },
    { body = ".*security", group = "<!-- 12 -->🛡️ Security" },
]
# protect breaking changes from being skipped due to matching a skipping commit_parser
protect_breaking_commits = false
# filter out the commits that are not matched by commit parsers
filter_commits = false
# regex for matching git tags
tag_pattern = "v[0-9].*"
# regex for skipping tags
skip_tags = "v0.1.0-beta.1"
# regex for ignoring tags
ignore_tags = ""
# sort the tags topologically
topo_order = false
# sort the commits inside sections by oldest/newest order
sort_commits = "oldest"
# limit the number of commits included in the changelog.
# limit_commits = 42

And here are the last two tags in my changelog:

# Changelog

All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines.

---
## [2.0.2](https://<repo>/compare/v2.0.1..v2.0.2) - 2024-04-16

### 🏡 Chore

- **(input)** increase unavailability risk to 0.2 - ([6094359](https://<repo>/commit/6094359662acbc0d4e377dfa53635b6145cc3f9d)) - tmlmt

---
## [2.0.1](https://<repo>/compare/v2.0.0..v2.0.1) - 2024-04-16

### 🩹 Fixes

- **(blabla)** unreliable date calculation - ([184ec38](https://<repo>/commit/184ec384e8119682c07efb2071fe6df6cc707ffc)) - tmlmt

### 🏡 Chore

- **(input)** update of production time - ([5dd2836](https://<repo>/commit/5dd2836b834cc5b998781139fedae8ac46f7b4a5)) - tmlmt
- **(todo)** add prioritization - ([5c73b45](https://<repo>/commit/5c73b457e460659d72d1e2d03df1d0d00dbe4c39)) - tmlmt

[orhun]

Hey @tmlmt sorry for the delay.

If I got it right, are you getting the following result with prepend?

# Changelog

All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines.

# Changelog

All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines.

<rest of the changelog>

Or are you referring to the tags (## [2.0.2]) while talking about "header"?

I don't see any issues with your configuration btw

[tmlmt]

Thanks for reverting! So basically, having a changelog like the one mentioned above then if I pushed a commit and then ran git cliff --unreleased --tag v2.0.3 --prepend CHANGELOG.md I would get:

# Changelog

All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines.

---
## [2.0.3](https://<repo>/compare/v2.0.2..v2.0.3) - 2024-04-25

### 🏡 Chore

- **(blabla)** did that - ([0505000](https://<repo>/commit/0123456689)) - tmlmt

---
# Changelog

All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines.

---
## [2.0.2](https://<repo>/compare/v2.0.1..v2.0.2) - 2024-04-16

### 🏡 Chore

- **(input)** increase unavailability risk to 0.2 - ([6094359](https://<repo>/commit/6094359662acbc0d4e377dfa53635b6145cc3f9d)) - tmlmt

---
## [2.0.1](https://<repo>/compare/v2.0.0..v2.0.1) - 2024-04-16

### 🩹 Fixes

- **(blabla)** unreliable date calculation - ([184ec38](https://<repo>/commit/184ec384e8119682c07efb2071fe6df6cc707ffc)) - tmlmt

### 🏡 Chore

- **(input)** update of production time - ([5dd2836](https://<repo>/commit/5dd2836b834cc5b998781139fedae8ac46f7b4a5)) - tmlmt
- **(todo)** add prioritization - ([5c73b45](https://<repo>/commit/5c73b457e460659d72d1e2d03df1d0d00dbe4c39)) - tmlmt

[orhun]

I see.

I came up with this repro script for your case:

git init
curl "https://paste.orhun.dev/git-cliff-384-repro.toml" >cliff.toml

git commit --allow-empty -m "feat: initial"
git commit --allow-empty -m "chore: first"
git tag v1
git cliff -o CHANGELOG.md

git commit --allow-empty -m "chore: second"
git cliff -u -t v2 --prepend CHANGELOG.md

Unfortunately the header isn't duplicated in this case. Can you confirm?