Handle files with is_file instead of file_exists

[solracsf]

Should fix things like fread(): read of 8192 bytes failed with errno=21 Is a directory since is_file() will return false if the given $path points to a directory, where file_exists() will return true if the given $path points to a valid file or directory.

Since we're expecting files only, this should make sense.

[MichaIng]

Both resolve symlinks, and return false, if the target does not exist, btw:

• https://www.php.net/manual/en/function.file-exists.php
• https://www.php.net/manual/en/function.is-file.php

EDIT: test -e vs test -f in shells, basically.

[solracsf]

Here is another explanation (just in case...):
https://blog.magepsycho.com/is_file-vs-file_exists/

[MichaIng]

Probably trivial enough, but @acsfer a rebase would be great, so CI checks can run through.

[solracsf]

@MichaIng rebased 👍

[MichaIng]

Tests need to be updated:

1) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeader with data set #0 ('/foo/bar.txt', false, '/foo/bar.txt')
Expectation failed for method name is "file_exists" when invoked 1 time(s).
Method was expected to be called 1 times, actually called 0 times.

2) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeader with data set #1 ('/foo/bar.txt.part', false, '/foo/bar.txt')
Expectation failed for method name is "file_exists" when invoked 1 time(s).
Method was expected to be called 1 times, actually called 0 times.

3) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeader with data set #2 ('/foo/bar.txt.ocTransferId7437493.part', false, '/foo/bar.txt')
Expectation failed for method name is "file_exists" when invoked 1 time(s).
Method was expected to be called 1 times, actually called 0 times.

4) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeader with data set #3 ('/foo/bar.txt.part', true, '/foo/bar.txt')
Expectation failed for method name is "readFirstBlock" when invoked 1 time(s)
Parameter 0 for invocation OC\Files\Storage\Wrapper\Encryption::readFirstBlock('/foo/bar.txt.part') does not match expected value.
Failed asserting that two strings are equal.
--- Expected
+++ Actual
@@ @@
-'/foo/bar.txt'
+'/foo/bar.txt.part'

[MichaIng]

There is a second occurrence, but not sure if it is relevant here, let's see what the drone says now: https://github.com/nextcloud/server/blob/is-file-handle/tests/lib/Files/Storage/Wrapper/EncryptionTest.php#L655

[skjnldsv]

There were 4 failures:
148 |  
149 | 1) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeaderAddLegacyModule with data set #0 (array('AES-128'), true, true, array('AES-128', 'OC_DEFAULT_MODULE'))
150 | Expectation failed for method name is "file_exists" when invoked 1 time(s).
151 | Method was expected to be called 1 times, actually called 0 times.
152 |  
153 | 2) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeaderAddLegacyModule with data set #1 (array(), true, false, array())
154 | Expectation failed for method name is "file_exists" when invoked 1 time(s).
155 | Method was expected to be called 1 times, actually called 0 times.
156 |  
157 | 3) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeaderAddLegacyModule with data set #2 (array(), true, true, array('OC_DEFAULT_MODULE'))
158 | Failed asserting that actual size 0 matches expected size 1.
159 |  
160 | /drone/src/tests/lib/Files/Storage/Wrapper/EncryptionTest.php:694
161 |  
162 | 4) Test\Files\Storage\Wrapper\EncryptionTest::testGetHeaderAddLegacyModule with data set #3 (array(), false, true, array())
163 | Expectation failed for method name is "file_exists" when invoked 1 time(s).
164 | Method was expected to be called 1 times, actually called 0 times.
165 |  

[skjnldsv]

/backport to stable22

[skjnldsv]

/backport to stable21

[skjnldsv]

/backport to stable20