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web pack source map not working for some devtool options. #5491
Do you want to request a feature or report a bug?
bug
What is the current behavior?
Sourcemap is not working for some devtool options. Tested options: eval: working cheap-eval-source-map: working cheap-source-map: not working cheap-module-eval-source-map: working cheap-module-source-map: not working source-map: not working inline-source-map: not working hidden-source-map: not working nosources-source-map: not working
If the current behavior is a bug, please provide the steps to reproduce.
It's really a weird issue. I am not sure any plugin causes this error. I do not think so. Just in case, you may check that in the repo. It is very basic sample repo and just used a couple webpack plugins such as html-webpack-plugin and copy-webpack-plugin. You can find those plugins' versions in package.json file. I suspect the compatibility between webpack and babel-loader.
What is the expected behavior?
source map should work in all devtool options.
If this is a feature request, what is motivation or use case for changing the behavior?
It's bug.
Please mention other relevant information such as the browser version, Node.js version, webpack version and Operating System.
"webpack": "^3.5.1",
Mac OS: 10.12.6
node: 8.2.1
Tested on Chrome 60, Mozilla 54, Safari 10.1
@MACSkeptic . Not really. I did not even specify UglifyJsPlugin in my config. Sourcemap is just not working properly when multiple entries are set to webpack. @petermikitsh , I still have the issue in Chrome, Firefox and Safari. That's interesting. Could you provide a sample repo? Maybe, I can test it as well and I can see that is it the same issue that I have?
#5569 provide a very simple sample repo. You can see it in it.
I'm the issuer. It seems that the webpack owner has no time to deal with the bug or he thinks it's NOT a bug. He may think we just use it in a wrong way , however it's obviouse that the bug is not reasonable. Now I feel frustrated.
Hey @yincu . It is already marked as an important bug. You cannot expect them to fix the bug right away as there are tons of bugs are on their list.
As I described in my first message, watch console.logs carefully. Otherwise, sourcemaps files are already created.
I just cloned my repo and did run it again. It is still a clear bug as you may see in the screenshot. Expecting behavior is that show the exact file and line. Not the bundled file. How about your console?
I get what you said. I reproduced the bug. However, it seems it may be a browser bug of chrome or it's NOT a bug.
When you browser http://localhost:3000/ page without a devtool window displayed. You'll get the right source map. Or if you get what you got in your above post picture. You can close the devtool window of chrome and open it again. Boom! You get what you want.
The source map files will not be get from the server unless you reopen the devtool window. These files are not expected to be acccesed by users when browsering the pages. They will not be downloaded along with the js or css files.
These files will only be downloaded and parsed when the devtool window is reopened.
It might be a browser bug, but it happens in other 3 browsers as well. Plus, it works fine with some other sourcemap types. Besides, it works as well if I assign only one entry to be bundled. I am not an expert and I cannot speak in a certain way, but it seems this bug is more related to webpack.
You could test this way with other sourcemap types to see if it works the same.
The test with the configuration devtool: 'source-map' suggests that it has nothing to do with webpack.
Source maps are used for debugging. The behavior of Chrome is reasonable .
Reacted by Søren Nguyen Boisen, Rémi Chanaud, Max, AceGentile and Bryan Hoang
Facing the same problem, it is uglifying when not told to and not having the devtool source map in cheap-source-map, source-map or any devtool option like inline-source-map.
Using webpack 4 with source-map option. It work in 20% of cases, even don't know how to reproduce it. Previously I use gulp, and gulp put source maps inside of js bundle. Webpack put source maps as separated file, think it is a root problem. Will try something like 'cheap-eval-source-map', hope it will help (latest version of chrome).
Fixed in webpack@4, Firefox has some problems with source maps, here more information #1194 (fixed in nightly)
I want to close this issue, because it is fixed, but if you faced with the problem again, feel free to open a new issue with reproducible test repo, we have many tests on source maps
Activity
NikhilVerma commentedon Aug 17, 2017
I am having the same problem right now. Eval source maps work fine.
Webpack: ^2.2.0
Chrome: 60.0.3112.101 (Official Build) (64-bit)
OSX: 10.12.6
petermikitsh commentedon Aug 19, 2017
Also experiencing this issue:
Webpack: 3.3.0
Chrome: Version 60.0.3112.101 (Official Build) (64-bit)
petermikitsh commentedon Aug 21, 2017
I've explored this further and my sourcemaps are working as expected in Firefox. Just not in Chrome.
MACSkeptic commentedon Aug 28, 2017
is that a similar issue to this? #5569 (comment)
SemihGk commentedon Aug 29, 2017
@MACSkeptic . Not really. I did not even specify UglifyJsPlugin in my config. Sourcemap is just not working properly when multiple entries are set to webpack. @petermikitsh , I still have the issue in Chrome, Firefox and Safari. That's interesting. Could you provide a sample repo? Maybe, I can test it as well and I can see that is it the same issue that I have?
yincu commentedon Aug 30, 2017
#5569 provide a very simple sample repo. You can see it in it.
I'm the issuer. It seems that the
webpackowner has no time to deal with the bug or he thinks it's NOT a bug. He may think we just use it in a wrong way , however it's obviouse that the bug is not reasonable. Now I feel frustrated.yincu commentedon Aug 30, 2017
I tested your project. It seemed no bug.

Browser: Chrome version: 59.0.3071.86
Operating system: windows 7 64bit
yincu commentedon Aug 30, 2017
And I updated the chrome to the newest version (60.0.3112.113). It still worked fine.
And the configuration is
devtool: 'source-map',SemihGk commentedon Aug 30, 2017
Hey @yincu . It is already marked as an important bug. You cannot expect them to fix the bug right away as there are tons of bugs are on their list.
As I described in my first message, watch console.logs carefully. Otherwise, sourcemaps files are already created.
I just cloned my repo and did run it again. It is still a clear bug as you may see in the screenshot. Expecting behavior is that show the exact file and line. Not the bundled file. How about your console?
yincu commentedon Aug 30, 2017
I get what you said. I reproduced the bug. However, it seems it may be a browser bug of chrome or it's NOT a bug.
When you browser http://localhost:3000/ page without a devtool window displayed. You'll get the right source map. Or if you get what you got in your above post picture. You can close the devtool window of chrome and open it again. Boom! You get what you want.
The source map files will not be get from the server unless you reopen the devtool window. These files are not expected to be acccesed by users when browsering the pages. They will not be downloaded along with the js or css files.
These files will only be downloaded and parsed when the devtool window is reopened.
SemihGk commentedon Aug 30, 2017
It might be a browser bug, but it happens in other 3 browsers as well. Plus, it works fine with some other sourcemap types. Besides, it works as well if I assign only one entry to be bundled. I am not an expert and I cannot speak in a certain way, but it seems this bug is more related to webpack.
yincu commentedon Aug 31, 2017
You could test this way with other sourcemap types to see if it works the same.
The test with the configuration
devtool: 'source-map'suggests that it has nothing to do with webpack.Source maps are used for debugging. The behavior of Chrome is reasonable .
junyuanz123 commentedon Oct 5, 2017
Got the same issue,
evalconfig works.3 remaining items
fix: try another method to generate sourcemap
devssh commentedon Apr 4, 2018
Facing the same problem, it is uglifying when not told to and not having the devtool source map in cheap-source-map, source-map or any devtool option like inline-source-map.
devssh commentedon Apr 4, 2018
Update: Just fixed it using mode in webpack 4
mbonaci commentedon Apr 26, 2018
@devssh so you get sourcemaps even with
devtool: "source-map", or what?Can you post your webpack config?
devssh commentedon Apr 26, 2018
Yes here is my baseConfig
Now in the dev server
What was added to fix the issue was
and it happened because we migrated from Webpack 3 to Webpack 4
cloakedninjas commentedon Jun 27, 2018
For some reason, not sure why, we've run into this bug too, will migrating to Webpack 4 fix this ?
But our SCSS sourcemaps generated by
gulp-sourcemapsare working fine, which makes me think this isn't a Chrome issueUpdate:

Do make sure they're not disabled in Chrome 🤦♂️
nelsonomuto commentedon Jul 5, 2018
Same thing here, can't get any sourcemaps other than
*-eval-*sourcemaps to work 😡matthias-ccri commentedon Sep 24, 2018
If the script is within an iframe, you have to enable "Search in anonymous and content scripts" in Chrome.
degr commentedon Nov 5, 2018
Using webpack 4 with source-map option. It work in 20% of cases, even don't know how to reproduce it. Previously I use gulp, and gulp put source maps inside of js bundle. Webpack put source maps as separated file, think it is a root problem. Will try something like 'cheap-eval-source-map', hope it will help (latest version of chrome).
Imad-MACHI commentedon Jul 7, 2020
I had the same problem in chrome, but it worked in firefox
alexander-akait commentedon Jul 7, 2020
Fixed in webpack@4, Firefox has some problems with source maps, here more information #1194 (fixed in nightly)
I want to close this issue, because it is fixed, but if you faced with the problem again, feel free to open a new issue with reproducible test repo, we have many tests on source maps
tomsaleeba commentedon May 3, 2021
Running on
webpack==4.41.2, the fix for me was settingsourceMap: truefor the TerserPlugin, as the docs highlight:This change meant I started to get source maps for all the available
devtoolvalues, not just theeval*ones.austinhaws commentedon May 10, 2021
Webpack 5 loses support for
sourceMap: trueTerser Plugin 5.0.0 release Notes
What is the equivalent option for webpack5?
oopses commentedon Jul 1, 2024
Webpack 5 devtools hidden-source-map not generate sourcemap