Perform code actions cross files in NeoVim

In this post, I'll take an example of the project I'm working on, which is the Apache SkyWalking project, but don't worry if you're not familiar with it, we will not dive into the project itself, but rather how to do code refactorings in NeoVim.

In a recent pull request I worked on, what I needed to do was to add a Java annotation @ElasticSearch.EnableDocValues to some fields cross many Java classes, you can preview the changes here.

Now, I have summarized which fields I need to add the annotation to, which are:

1. Fields with another Java annotation @Column(name = ...)
2. I only need to add @ElasticSearch.EnableDocValues to the fields whose name value in @Column(name = ...) are the following values:

• COMPONENT_ID
• COMPONENT_IDS
• TIMESTAMP
• START_TIME
• ENTITY_ID
• TAG_KEY
• LATENCY
• START_TIME_SECOND
• START_TIME_NANOS
• VALUE
• TIME_BUCKET
• PERCENTAGE
• OPERATION_TIME
• CREATE_TIME
• OPERATION_TIME
• DUMP_TIME
• SEQUENCE
• TRACE_ID
• TIMESTAMP_MILLIS

Now here is how I did it.

Populate the quickfix list that need to be modified

The first step is to populate the quickfix list with the files that need to be modified. To do this, I can use the following command to find and add the files to the quickfix list:

:grep "@Column(.*\(COMPONENT_ID\|COMPONENT_IDS\|TIMESTAMP\|START_TIME\|ENTITY_ID\|TAG_KEY\|LATENCY\|START_TIME_SECOND\|START_TIME_NANOS\|VALUE\|TIME_BUCKET\|PERCENTAGE\|OPERATION_TIME\|CREATE_TIME\|OPERATION_TIME\|DUMP_TIME\|SEQUENCE\|TRACE_ID\|TIMESTAMP_MILLIS\)" **/src/**/*.java

After the quickfix list is populated, I can use the following command to get a glimpse of how many files that need to be modified:

:echo len(getqflist())

It shows there are 83 fields that need to be modified. You can also use the following command to open the quickfix window to see the list of files:

:copen

Add the annotation to the fields

Now that I have the list of files that need to be modified, I can use the :norm command to perform some operations in command mode, i.e. add the annotation above the fields. Here is the command that I used:

:cdo norm! O@ElasticSearch.EnableDocValues | update

• The :cdo command is used to execute a command in each file location in the quickfix list.
• The norm! command is used to execute a normal mode command. In this case, I used O to firstly add a new line above the current line and then add the annotation @ElasticSearch.EnableDocValues.
• The | update command is used to save the changes to the file.

OK, now that every field needed to be modified has been added with the annotation, here comes the hardest part, before I added the @ElasticSearch.EnableDocValues annotation, the original file might or might not have the correct import statement for the annotation class, so after I added the annotation, there might be many compilation errors. So I need to add the missing import statements to the files, but I don't want to add a duplicate import statement if it already exists in the file.

Add the missing import statements

In order to add the missing import statements, I can use the Code Actions feature in NeoVim's LSP, let's see how to import the annotation class @ElasticSearch.EnableDocValues in a single file first:

1. Move the cursor to the begginning of the file by pressing gg
2. Go the the next error diagnostic by pressing ]e
3. Press <leader>ca to show the available code actions

I can see in the popup there is an option Import 'ElasticSearch' (org.apache.skywalking.oap.server.core.storage.annotation.ElasticSearch) along with other code actions, I can press <Enter> directly to apply the first code action.

Now, how to perform the import code actions to all locations in the quickfix list? Here is how I did it:

1. First, I need to move the cursor to the beginning of each file by pressing gg:

:cfdo norm gg

2. Now I can move the cursor to the next error diagnostic, and apply the "import" code action by searching the Import keyword in the popup and press <Enter>, I can do this by running multiple Lua scripts in the command line:

:cfdo lua vim.diagnostic.goto_next({ severity = "error" }); vim.lsp.buf.code_action({filter = function(ca) return ca.title:find('Import', 1, true) == 1 end, apply = true})

Let's break down the command:

• :cfdo is used to execute the command in each file in the quickfix list, I use cfdo in this case instead of cdo because I only need to perform the import action in each file only once, even if there are multiple @ElasticSearch.EnableDocValues annotations in that file, thus avoiding duplicated import statements.
• lua is used to execute a Lua script.
• vim.diagnostic.goto_next({ severity = "error" }) is used to move the cursor to the next error diagnostic.
• vim.lsp.buf.code_action is used to show the code actions popup, but I don't want the results to be a popup, I want to filter the single code action I want and directly apply it.
  • filter = function(ca) return ca.title:find('Import', 1, true) == 1 end is used to filter the code actions whose title starts with Import, which is what I want.
  • apply = true is used to apply the first matching code action directly, and thus no popup and interactive selection is needed.

After running the command, I can see there might be some info messages:

No more valid diagnostics to move to

which is because some files might already have the correct imports because other fields in the same file might be already using the annotation @ElasticSearch.<other-annotation>. But anyhow I can see the missing import statements are added to the files, and the compilation errors are gone.