Handle assignments to global variables from the init function

[k4n4ry]

fixes #56

• Added logic in GlobalAnalyzer's run() to retrieve the init function from the file.
• Within getGlobalConsumers(), analyzed assignments to global variables from the init function and used it as one of the criteria for determining consumer creation.

Please provide comments if this implementation differs from nilaway's coding practices or design principles. Thank you.

[CLAassistant]

All committers have signed the CLA.

[sonalmahajan15]

@k4n4ry, thank you for submitting the PR! We'll take a look soon and follow up with you.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 96.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 87.70%. Comparing base (c91e71c) to head (9c61f48).

Files with missing lines	Patch %	Lines
assertion/global/analyzer.go	92.85%	1 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #253 +/- ## ========================================== + Coverage 87.60% 87.70% +0.09% ========================================== Files 63 63 Lines 7916 7961 +45 ========================================== + Hits 6935 6982 +47 + Misses 799 798 -1 + Partials 182 181 -1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[SongShawn]

package sxn01

var (
    b *int
)

func init() {
    init_b_val()
}

func init_b_val() {
    b = new(int)
}

func use_global_var() {
    *b = 20
}

The above code triggers a false positive

[k4n4ry]

@SongShawn Thanks for the review. I've updated the function to retrieve not only the init functions but also all functions called directly or indirectly from them. https://github.com/uber-go/nilaway/pull/253/commits/dce532a2509d6ebfb1452310abf809847b289370

[k4n4ry]

@sonalmahajan15 Hello, could you please rerun the CI and review this code? Thank you.

[yuxincs]

I'm updating your branch since we recently merged CI fixes, which are required for the CI to pass on forked repositories. I'll review the code this week :)

[github-actions[bot]]

Golden Test

[!WARNING]
❌ NilAway errors reported on stdlib are different 📉.

3271 errors on base branch (main, c91e71c) 2968 errors on test branch (69d920e)

Diffs

```diff + /opt/hostedtoolcache/go/1.22.6/x64/src/archive/tar/writer.go:536:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - tar/writer.go:533:26: passed as parameter `b` to `regFileWriter.Write()` (implementing `Writer.Write()`) + - tar/writer.go:536:7: function parameter `b` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/archive/tar/writer.go:576:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - tar/writer.go:573:29: passed as parameter `b` to `sparseFileWriter.Write()` (implementing `Writer.Write()`) + - tar/writer.go:576:7: function parameter `b` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/md5/md5.go:128:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - io/multi.go:83:23: passed as parameter `p` to `multiWriter.Write()` (implementing `Writer.Write()`) + - io/multi.go:85:20: function parameter `p` passed as arg `p` to `Write()` + - md5/md5.go:111:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - md5/md5.go:128:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/md5/md5.go:128:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - md5/md5.go:111:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - md5/md5.go:128:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/sha1/sha1.go:134:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - io/multi.go:83:23: passed as parameter `p` to `multiWriter.Write()` (implementing `Writer.Write()`) + - io/multi.go:85:20: function parameter `p` passed as arg `p` to `Write()` + - sha1/sha1.go:123:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - sha1/sha1.go:134:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/sha1/sha1.go:134:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - sha1/sha1.go:123:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - sha1/sha1.go:134:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/sha256/sha256.go:190:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - io/multi.go:83:23: passed as parameter `p` to `multiWriter.Write()` (implementing `Writer.Write()`) + - io/multi.go:85:20: function parameter `p` passed as arg `p` to `Write()` + - sha256/sha256.go:179:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - sha256/sha256.go:190:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/sha256/sha256.go:190:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - sha256/sha256.go:179:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - sha256/sha256.go:190:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/sha512/sha512.go:269:7: Potential nil panic detected. Observed nil flow from source to dereference point: + - fmt/print.go:170:11: literal `nil` assigned into field `buf` + - fmt/print.go:225:19: field `buf` passed as arg `p` to `Write()` + - io/multi.go:83:23: passed as parameter `p` to `multiWriter.Write()` (implementing `Writer.Write()`) + - io/multi.go:85:20: function parameter `p` passed as arg `p` to `Write()` + - sha512/sha512.go:256:18: passed as parameter `p` to `digest.Write()` (implementing `Writer.Write()`) + - sha512/sha512.go:269:7: function parameter `p` sliced into + /opt/hostedtoolcache/go/1.22.6/x64/src/crypto/sha512/sha512.go:269:7: Potential nil panic detected. Observed nil flow from source to dereference point ...(truncated)... l panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - rand/example_test.go:53:27: global variable `Stdout` passed as arg `output` to `NewWriter()` - - tabwriter/tabwriter.go:599:26: function parameter `output` passed as arg `output` to `Init()` - - tabwriter/tabwriter.go:212:13: function parameter `output` assigned into field `output` - - tabwriter/tabwriter.go:251:12: field `output` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/tabwriter/tabwriter.go:251:12: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - tabwriter/example_test.go:17:9: global variable `Stdout` passed as arg `output` to `Init()` - - tabwriter/tabwriter.go:212:13: function parameter `output` assigned into field `output` - - tabwriter/tabwriter.go:251:12: field `output` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/tabwriter/tabwriter.go:251:12: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - tabwriter/example_test.go:26:9: global variable `Stdout` passed as arg `output` to `Init()` - - tabwriter/tabwriter.go:212:13: function parameter `output` assigned into field `output` - - tabwriter/tabwriter.go:251:12: field `output` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/tabwriter/tabwriter.go:251:12: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - tabwriter/example_test.go:43:27: global variable `Stdout` passed as arg `output` to `NewWriter()` - - tabwriter/tabwriter.go:599:26: function parameter `output` passed as arg `output` to `Init()` - - tabwriter/tabwriter.go:212:13: function parameter `output` assigned into field `output` - - tabwriter/tabwriter.go:251:12: field `output` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/tabwriter/tabwriter.go:251:12: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - tabwriter/example_test.go:61:27: global variable `Stdout` passed as arg `output` to `NewWriter()` - - tabwriter/tabwriter.go:599:26: function parameter `output` passed as arg `output` to `Init()` - - tabwriter/tabwriter.go:212:13: function parameter `output` assigned into field `output` - - tabwriter/tabwriter.go:251:12: field `output` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/tabwriter/tabwriter.go:251:12: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - v2/example_test.go:54:27: global variable `Stdout` passed as arg `output` to `NewWriter()` - - tabwriter/tabwriter.go:599:26: function parameter `output` passed as arg `output` to `Init()` - - tabwriter/tabwriter.go:212:13: function parameter `output` assigned into field `output` - - tabwriter/tabwriter.go:251:12: field `output` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/template/funcs.go:635:2: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - template/example_test.go:104:22: global variable `Stdout` passed as arg `w` to `HTMLEscape()` - - template/escape.go:970:22: function parameter `w` passed as arg `w` to `HTMLEscape()` - - template/funcs.go:635:2: function parameter `w` called `Write()` - /opt/hostedtoolcache/go/1.22.6/x64/src/text/template/funcs.go:718:2: Potential nil panic detected. Observed nil flow from source to dereference point: - - os/file_unix.go:108:10: literal `nil` returned from `NewFile()` in position 0 - - os/file.go:66:2: result 0 of `NewFile()` assigned into global variable `Stdout` - - template/example_test.go:109:20: global variable `Stdout` passed as arg `w` to `JSEscape()` - - template/escape.go:986:20: function parameter `w` passed as arg `w` to `JSEscape()` - - template/funcs.go:718:2: function parameter `w` called `Write()` ```